| AgencyCode | AgencyDescr | PrimaryContact | City | Email | LastUpdateDate |
| 2NDNATURE | 2NDNATURE, LLC | Krista McDonald | Santa Cruz | krista@2ndnaturellc.com | 2017-10-13 |
| 4MARBLES | 4Marbles, Inc. | Lee Tremblay | | eetremblay@4marbles.org | 2013-10-01 |
| ABL | A & B Laboratories | | | | 2017-06-05 |
| ALWAL | A & L Western Agricultural Laboratories, Inc. | | Modesto | | 2012-08-30 |
| A1ANAL | A-1 Analytical Labs, Salinas | | | | 2017-06-05 |
| CIWQS 553 | AAF-McQuay, Inc | | | | 1900-01-01 |
| ABALONE | Abalone Coast Analytical | Amanda Smith | San Luis Obispo | amanda.smith@abalonecoastanalytical.com | 2015-12-21 |
| ACCULAB | Acculab Environmental Services | | | | 2017-06-05 |
| Acterra | Acterra | | Palo Alto | | 2015-10-05 |
| ACUREX | Acurex Analytical Chemistry Lab | | | | 2017-06-05 |
| ADH | ADH Environmental | Christian Kocher | Soquel | ckocher@adhenvironmental.com | 2012-08-30 |
| ATL | Advanced Technology Laboratories | | Signal Hill | | 2017-02-13 |
| AD_SCI | Adventure Scientists | | | | 2017-05-01 |
| AECOM | AECOM | Amy Gardner | San Diego | Amy.Gardner@aecom.com | 2012-12-07 |
| AECOM-Oakland | AECOM Oakland Office | | Oakland | | 2023-05-22 |
| AECOM-Sacramento | AECOM Sacramento Office | Steve Pagliughi | Sacramento | Steve.Pagliughi@aecom.com | 2018-01-31 |
| CIWQS 854 | Aerojet General Corp | | | | 1900-01-01 |
| AEROJET | Aerojet TechSystems | | | | 2017-06-05 |
| Not Recorded | Agency Not Recorded | | | | 2007-09-01 |
| AHC | Agoura Hills City | | | | 2018-09-22 |
| AGTECH | Agricultural Technology Services Lab | | | | 2017-06-05 |
| APPL | Agriculture & Priority Pollutants Laboratories, Inc | | Fresno | | 2007-09-01 |
| ALBL | Air Liquide Balazs Laboratories | | | | 2017-06-05 |
| AlamedaCounty | Alameda County | | | | 2017-06-08 |
| ACFCWCD | Alameda County Flood Control & Water Conservation District | | | | 2014-08-04 |
| ACPWA | Alameda County Public Works Agency | | | | 2014-08-04 |
| ACWD | Alameda County Water District | | | | 2017-06-28 |
| ACCWP | Alameda Countywide Clean Water Program | Arleen Feng | Hayward | arleen@acpwa.org | 2016-03-24 |
| Albany | Albany City Dept Public Works | Ray Chan | Albany | rchan@albanyca.org | 2016-06-15 |
| Algalita | Algalita | | | | 2008-01-01 |
| AWMA | Aliso Water Management Authority | Ann Harley | Dana Point | | 2012-05-07 |
| APP | All Positives Possible | | Richmond | allpositivesp@yahoo.com | 2025-06-26 |
| AlphaAnalytical_MA | Alpha Analytical - Mansfield, MA | | Mansfield | | 2025-05-12 |
| ALPHA_San Diego | Alpha Analytical Laboratories Inc., San Diego | | Carlsbad | | 2024-01-23 |
| ALPHA_Ukiah | Alpha Analytical Laboratories Inc., Ukiah | | Ukiah | clientservices@alpha-labs.com | 2016-07-05 |
| ALPHA | Alpha Analytical, Inc. | | Sparks | | 2007-09-01 |
| AWG | Alpine Watershed Group | AWG | Woodfords | alpinewatershed@gmail.com | 2017-03-30 |
| ALS | ALS Laboratory Group | | Salt Lake City | | 2013-10-28 |
| ALTA | Alta Environmental | Kathy Hubbard | Long Beach | kathy.hubbard@altaenviron.com | 2013-08-06 |
| CIWQS 1406 | Alturas City | | | | 1900-01-01 |
| AmadorCounty | Amador County | | | | 2017-06-08 |
| AMEC | AMEC Environment & Infrastructure | Tyler Huff | San Diego | tyler.huff@amec.com | 2011-08-08 |
| AMERANAL | American Analytical Lab | | | | 2017-06-05 |
| CIWQS 1520 | AMERICAN CANYON CITY | | | | 1900-01-01 |
| AEMC | American Environmental Management Corporation | | | | 2017-06-05 |
| AETL | American Environmental Testing Laboratories | | | | 2017-08-29 |
| AETL_RC | American Environmental Testing Laboratory, Inc., Rancho Cordova | | Rancho Cordova | | 2019-06-03 |
| ARC | American River Conservancy | | Lotus | | 2010-10-19 |
| AR | American Rivers | Maiya Greenwood | Nevada City | mgreenwood@americanrivers.org | 2017-04-25 |
| AMERWW | American Water Works, Bellville | | | | 2017-06-05 |
| CIWQS 3211 | Ameripride Services Inc | | | | 1900-01-01 |
| AMTECH | Amtech Laboratories | | | | 2017-06-05 |
| ANACON | ANACON, Inc. | James Lee | Houston | | 2012-08-30 |
| ACWDL | Anaheim City Water Quality Laboratory | | | | 2017-06-05 |
| ANARES | Analytical Resources, Inc. | | Tukwila | | 2015-03-24 |
| AS | Analytical Sciences, LLC | | Petaluma | | 2014-04-21 |
| ANALTECH | Analytical Technologies, Inc. Lab | | | | 2017-06-05 |
| ANAMETRIX | Anametrix | | | | 2017-06-05 |
| ANATEC | Anatec Labs, Inc. | | | | 2017-06-05 |
| AnchorQEA | Anchor QEA | Andrew Martin or Ivy Fuller | Seattle | amartin@anchorqea.com | 2015-11-16 |
| CIWQS 1728 | Anderson City | | | | 1900-01-01 |
| CIWQS 1797 | Angels City | | | | 1900-01-01 |
| ADSL | Anlab-Dewante and Stowell Lab | | | | 2017-06-05 |
| AVEK | Antelope Valley - East Kern Water Agency | | | | 2017-06-05 |
| AWTP | Antioch Water Treatment Plant | | | | 2017-06-05 |
| APGL | AP Genomic Labs Inc. | | Carlsbad | info@apgenomiclabs.com | 2024-12-18 |
| AMS-CA | Applied Marine Sciences, Inc. California | Paul Salop | Livermore | salop@amarine.com | 2007-12-21 |
| AMSLabs | Applied Microbiological Services | Versha Patel | Long Beach | versha@amslabs.com | 2016-08-19 |
| APCL | Applied P & Ch Laboratories, Inc. | Unknown | Chino | | 2012-05-07 |
| AREL | Applied Remediation Environmental Lab | | | | 2017-06-05 |
| ARS | Applied River Sciences | | Arcata | info@riversciences.com | 2026-02-17 |
| AQUALAB | AquaLab | | | | 2017-06-05 |
| AquaSci | AquaScience | Mike Miller | Davis | Aquasci@aol.com | 2007-09-01 |
| AA | Aquatic Analysts | Jim Sweet | Friday Harbor | | 2018-03-05 |
| ABCL | Aquatic Bioassay and Consulting Laboratories, Inc. | Michael Machuzak | Ventura | aquabio@pacbell.net | 2011-10-12 |
| ABL_Chico | Aquatic Bioassessment Lab - Chico | Shawn McBride | | Shawn.McBride@wildlife.ca.gov | 2019-09-23 |
| DFW-ABL | Aquatic Bioassessment Lab - DFW | | | | 2007-09-01 |
| ABA | Aquatic Biology Associates, Inc. | Robert Wisseman | Corvalis | AQUATICBIO@MAC.COM | 2011-11-02 |
| AET | Aquatic EcoTechnologies, LLC | Alle Lie | Santa Cruz | alle@aquaticecotechnologies.com | 2020-09-23 |
| ARI | Aquatic Research, Inc. | | Seattle | info@aquaticresearchinc.com | 2014-10-06 |
| DFW-ATL | Aquatic Toxicology Laboratory | Brian Finlayson | Elk Grove | Friley@ospr.dfg.ca.gov | 2007-09-01 |
| CIWQS 1988 | Arcata City | | | | 1900-01-01 |
| ACWL | Arcata City Water Laboratory | | | | 2017-06-28 |
| ALA | Arrowhead Lake Association | | | | 2023-07-12 |
| ARROWHEAD | Arrowhead Puritas | | | | 2017-06-05 |
| AGCity | Arroyo Grande City | Geoff English | Arroyo Grande | | 2016-01-04 |
| ASBESTOSTEM | Asbestos TEM Laboratories, Inc. | | | | 2017-06-05 |
| AssocLabs | Associated Laboratories | | Orange | | 2013-10-01 |
| AL | Assoicated Laboratories | Unknown | Orange | | 2012-05-07 |
| AEHL | Atkins Environmental Help Labs | | | | 2017-06-05 |
| CIWQS 2372 | Atwater City | | | | 1900-01-01 |
| CIWQS 2383 | Auburn City | | | | 1900-01-01 |
| CIWQS 3672 | Avalon City | | | | 1900-01-01 |
| CIWQS 2475 | Avila Beach CSD | | | | 1900-01-01 |
| AXYS | AXYS Analytical Services Ltd. | Pamela Riley | Sidney | priley@axys.com | 2011-06-09 |
| BBL | B and B Laboratories, Inc. | Juan Ramirez | College Station | juanramirez@tdi-bi.com | 2011-08-04 |
| Babcock | Babcock Laboratories | Jim Reid | Riverside | lchrystal@babcocklabs.com | 2007-09-01 |
| Babcock_ElCentro | Babcock Laboratories, El Centro | | | | 2021-10-19 |
| Bachand | Bachand & Associates | Philip Bachand | Davis | philip@bachandassociates.com | 2020-03-30 |
| CIWQS 40631 | BAE Systems San Diego Ship Repair Inc | | | | 1900-01-01 |
| Balance | Balance Hydrologics, Inc. | Chris White | Berkeley | cwhite@balancehydro.com | 2012-11-23 |
| BARRINGER | Barringer Laboratories, Inc. | | | | 2017-06-05 |
| BAL | Basic Laboratory, Inc. | Matt Rose | Redding | mrose@basiclabinc.com | 2007-09-01 |
| BASMAA_RMC | BASMAA Regional Monitoring Coalition | | | | 2012-11-15 |
| Battelle-MA | Battelle Marine Sciences Laboratory - MA | | Duxbury | | 2007-12-21 |
| Battelle-WA | Battelle Marine Sciences Laboratory - WA | Brenda Lasorsa | Sequim | Brenda.lasorsa@pnl.gov | 2007-12-21 |
| BCA | Battle Creek Alliance | Marily Woodhouse | Manton | battlecreekalliance@gmail.com | 2019-01-08 |
| BCWC | Battle Creek Watershed Conservancy | | Manton | sptussing@earthlink.net | 2014-08-10 |
| BACWA | Bay Area Clean Water Agencies | | | | 2017-06-05 |
| BADA | Bay Area Dischargers' Association - Local Effects Monitoring | | | | 2007-12-21 |
| BAMSC_RMC | Bay Area Municipal Stormwater Collaborative Regional Monitoring Coalition | | | | 2024-10-03 |
| BART | Bay Area Rapid Transit District | | | | 2019-01-07 |
| BCL | BC Laboratories, Inc. | Aileen Cantorna | Bakersfield | bclabs@bclabs.com | 2007-09-01 |
| CIWQS 4251 | Bear Valley CMSD | | | | 1900-01-01 |
| CIWQS 4256 | Bear Valley Water District (Bear Valley, CA) | | | | 1900-01-01 |
| CIWQS 445907 | Beaumont City | | | | 1900-01-01 |
| CIWQS 4343 | Bell Carter Olive Company Inc | | | | 1900-01-01 |
| CIWQS 4357 | Bella Vista Water District | | | | 1900-01-01 |
| BendGX | Bend Genetics LLC | Tim Otten | Sacramento | | 2017-12-05 |
| CIWQS 4406 | Benicia City | | | srovanpera@ci.benicia.ca.us | 2018-01-30 |
| BCWTPL | Benicia City Wastewater Treatment Plant Laboratory, Lake Herman | | | | 2017-06-05 |
| CIWQS 4484 | Berry Petroleum Company | | | | 1900-01-01 |
| BBMWD | Big Bear Municipal Water District | | | | 2020-10-29 |
| BVB_Pomo | Big Valley Band of Pomo Indians | Sarah Ryan | Lakeport | sryan@big-valley.net | 2018-02-21 |
| BAS | BioAssessment Services | Tom King | Folsom | jtkbioassess@gmail.com | 2012-08-30 |
| BTRL | Biological Testing & Research Laboratory | | | | 2017-06-05 |
| BiovirLab | Biovir Laboratories | | | | 2011-06-14 |
| BOLSA | Bolsa Analytical Laboratory | | | | 2017-06-05 |
| BRANCIFORTE | Branciforte Laboratories, Watsonville | | | | 2017-06-05 |
| BSKL | Braun, Skaggs and Kevorkian Lab | | | | 2017-06-05 |
| CIWQS 5169 | Brawley City | | | | 1900-01-01 |
| BRL | Brelje and Race Laboratories, Inc. | Ann Hill | Santa Rosa | | 2007-09-01 |
| CIWQS 148431 | Brentwood City | | | | 1900-01-01 |
| BA | Brooks Applied Labs | Tiffany Stillwater | Bothell | Tiffany@brooksapplied.com | 2016-06-23 |
| BR | Brooks Rand Labs | Elizabeth Madonick | Seattle | elizabeth@brooksrand.com | 2007-12-21 |
| BRWNCALD | Brown and Caldwell | Eileen Wiegele | San Diego | ewiegele@brwncald.com | 2014-09-04 |
| BrCaL-Emeryville | Brown and Caldwell Lab, Emeryville | | | | 2017-06-05 |
| BrCaL-Pasadena | Brown and Caldwell Lab, Pasadena | | | | 2017-06-05 |
| BrCaL | Brown and Caldwell Laboratories | Michael Flake, P.E. | Walnut Creek | | 2014-07-09 |
| BBWTPL | Bryte Bend Water Treatment Plant Laboratory | | | | 2017-06-28 |
| BSA_Env | BSA Environmental Servises, Inc. | | Beachwood | | 2024-04-03 |
| BSK | BSK Analytical Laboratory | Brenda Lasorsa | Sequim | Brenda.lasorsa@pnl.gov | 2007-09-01 |
| BSK-Fresno | BSK Associates Fresno | Belinda Vega | | bvega@bskassociates.com | 2023-10-31 |
| BSK-RanchoCordova | BSK Associates Rancho Cordova | Brenda Hamilton | | bhamilton@bskassociates.com | 2023-10-31 |
| BVC | Buena Vista Coalition | Tim Ashlock | Buttonwillow | tim@bvh2o.com | 2013-09-12 |
| BVWSD | Buena Vista Water Storage District | Dan Bartel | Buttonwillow | | 2008-01-01 |
| CIWQS 6656 | Burbank City DPW | | | | 1900-01-01 |
| BLM | Bureau of Land Management | Andy Hamilton | Klamath Falls | andy_hamilton@blm.gov | 2012-04-20 |
| BureauVeritas_Miss | Bureau Veritas Laboratories, Mississauga | | Mississauga | | 2025-07-03 |
| BCWTP | Burlingame City Wastewater Treatment Plant | | | | 2017-06-05 |
| CIWQS 5597 | Burney Forest PWR/Shasta Green | | | | 1900-01-01 |
| ButteCounty | Butte County | | | | 2017-06-08 |
| BCPHD | Butte County Public Health Department | | Oroville | phinfo@buttecounty.net | 2025-11-07 |
| CLTECH | C.L. Technology, Inc. | | | | 2017-06-05 |
| CDSH-Napa | CA Department of State Hospitals-Napa | | | | 2022-09-09 |
| DWR-MWQI | CA Department of Water Resources - Municipal Water Quality Investigations | | West Sacramento | | 2015-09-21 |
| CIWQS 6913 | CA Dept of Corrections | | | | 1900-01-01 |
| CIWQS 6912 | CA Dept of Corrections Imperial | | | | 1900-01-01 |
| CIWQS 6904 | Ca Dept of Corrections San Luis Obispo | | | | 1900-01-01 |
| CIWQS 6896 | CA Dept of Fish & Game Fresno | | | | 1900-01-01 |
| CIWQS 6940 | Ca Dept of Fish & Game Independence | | | | 1900-01-01 |
| CIWQS 6930 | Ca Dept of Fish & Game Nimbus | | | | 1900-01-01 |
| CIWQS 6934 | Ca Dept of Fish & Wildlife Hornbrook | | | | 1900-01-01 |
| CIWQS 6927 | Ca Dept of Fish & Wildlife Redding | | | | 1900-01-01 |
| CDFA_Berkeley | CA Dept of Food and Agriculture Lab, Berkeley | | | | 2017-06-05 |
| CDHS_Berkeley | CA Dept of Health Services Lab, Berkeley | | | | 2017-06-05 |
| CDHS_LosAngeles | CA Dept of Health Services Lab, Los Angeles | | | | 2017-06-05 |
| CIWQS 6995 | Ca Dept of Parks & Rec Sacramento Headquaters | | | | 1900-01-01 |
| CIWQS 7123 | Ca Dept of Parks & Rec Tahoma | | | | 1900-01-01 |
| CALTRANSD1 | CA Dept of Transportation District 1, Eureka | | | | 2017-06-05 |
| CALTRANSD2 | CA Dept of Transportation District 2, Redding | | | | 2017-06-05 |
| CIWQS 7046 | Ca Dept of Water Resources Pearblossom | | | | 1900-01-01 |
| CASG-MLML | CA Sea Grant at Moss Landing Marine Laboratories | Rick Starr | Moss Landing | starr@mlml.calstate.edu | 2009-09-22 |
| CASG-RRSSMP | CA Sea Grant Russian River Salmon and Steelhead Monitoring Program | | | | 2019-11-26 |
| CSUSD-WIRL_SWL | CA State University San Diego - Water Innovation Research Laboratory (WIRL) & Safe WaTER Research Lab (SWL) | Natalie Mladenov | San Diego | nmladenov@sdsu.edu | 2020-10-29 |
| CUSA_TST | CA Urban Streams Alliance-The Stream Team | | | | 2018-03-12 |
| CIWQS 7164 | Cabrillo Power I LLC | | | | 1900-01-01 |
| Cabrillo | Cabrillo Power I, LLC | | | | 2021-03-03 |
| CalabasasCity | Calabasas City | | | | 2018-09-22 |
| CIWQS 7274 | Calaveras Cnty Water District | | | | 1900-01-01 |
| CIWQS 7281 | Calaveras Trout Farm, Inc | | | | 1900-01-01 |
| CIWQS 8661 | Calexico City | | | | 1900-01-01 |
| CAD_TWG | California Algae and Diatom Taxonomic Working Group | Lilian Busse | San Diego | http://www.cad-twg.org/ | 2012-01-17 |
| CAWC | California American Water Company | | | | 2017-06-05 |
| CAWC-Monterey | California American Water Company Lab, Monterey | | | | 2017-06-05 |
| CALANAL | California Analytical Lab | | | | 2017-06-05 |
| CCC | California Coastal Commission | | | | 2017-05-01 |
| CDFW-R4 | California Department of Fish and Wildlife, Central Region 4 | | Fresno | reg4assistant@wildlife.ca.gov | 2026-02-17 |
| CDFW-R1 | California Department of Fish and Wildlife, Northern Region 1 | | Eureka | | 2026-03-30 |
| CDFA | California Department of Food and Agriculture, Center for Analytical Chemistry | Stephen Siegel | Sacramento | ssiegel@cdfa.ca.gov | 2008-01-01 |
| CADeptParksGFD | California Department of Parks and Recreation - Gold Fields District | | Folsom | | 2022-05-23 |
| DPR | California Department of Pesticide Regulation | | Sacramento | | 2015-06-24 |
| CDPH | California Department of Public Health | | Richmond | | 2015-03-30 |
| Caltrans | California Department of Transportation | Bhaskar Joshi | | | 2015-04-23 |
| DWR-ND | California Department of Water Resources, Northern District | Ryan Martin | Red Bluff | | 2007-09-01 |
| CLS | California Laboratories Services | Raymond Oslowski, Jr. | Rancho Cordova | rayo@californialab.com | 2007-09-01 |
| CalPoly_SLO | California Polytechnic State University San Luis Obispo | Chri Surfleet | | csurflee@calpoly.edu | 2018-05-10 |
| CalPoly_HSU | California Polytechnic State University, Humboldt | | | | 2024-03-18 |
| CRC | California Rice Commission | Tim Johnson, Roberta Firoved | Sacramento | tjohnson@calrice.org, rfiroved@calrice.org | 2009-09-24 |
| CA_SCC | California State Coastal Conservancy | | | | 2023-12-28 |
| CSP-MC | California State Park Malibu Creek | | | | 2018-09-22 |
| CSP-Angeles | California State Parks Angeles District | | | | 2017-12-22 |
| CSUS | California State University at Sacramento | Tod Granicher | Sacramento | tod.granicher@owp.csus.edu | 2017-01-09 |
| CSUCI | California State University Channel Islands | | | | 2013-04-03 |
| CSULB | California State University Long Beach | Dessie Underwood | Long Beach | dlunderw@csulb.edu | 2012-08-30 |
| CSULB-IIRMES | California State University Long Beach Institute for Integrated Research in Materials, Environments, and Society | Rich Gossett | Long Beach | richgossett@yahoo.com | 2010-03-23 |
| CSULB-SEAL | California State University Long Beach Stream Ecology and Assessment Laboratory | Dessie Underwood | Long Beach | dlunderw@csulb.edu | 2012-04-17 |
| CSUMB | California State University Monterey Bay | Marc Los Huertos | Seaside | | 2011-10-31 |
| CSUMB-WEE | California State University Monterey Bay Watershed Environment and Ecology Lab | John Olson | Seaside | joolson@csumb.edu | 2019-04-30 |
| CSUSB | California State University San Bernardino | | | | 2013-04-09 |
| CSUSD-Biology | California State University, San Diego - Department of Biology | | | | 2025-02-06 |
| CSUSM | California State University, San Marcos | Robert Sheath | | | 2008-04-24 |
| CSUStan-CL | California State University, Stanislaus - Cover Lab | Matthew R. Cover | Turlock | mcover@biology.csustan.edu | 2010-07-07 |
| CTC | California Tahoe Conservancy | Jenna Hooper | Tahoe | jhooper@tahoe.ca.gov | 2013-06-14 |
| CalTrout | California Trout | Janet Hatfield | Mammoth Lakes | janet@inyo-monowater.org | 2013-10-16 |
| CALWATLAB | California Water Labs | | | | 2017-06-05 |
| CALWATER | California Water Service Company Lab | | | | 2017-06-05 |
| CIWQS 7483 | CALIPATRIA CITY | | | | 1900-01-01 |
| CIWQS 7485 | Calistoga City | | | | 1900-01-01 |
| CIWQS 7514 | CALMAT COMPANY | | | | 1900-01-01 |
| CALSCI | CalScience Laboratories | Bob Stearns | Garden Grove | bstearns@calscience.com | 2007-09-01 |
| CALTEST | CalTest Analytical Laboratory | Christine Horn | Napa | caltest@caltestlab.com | 2007-09-01 |
| CIWQS 10191 | Camarillo Sanitary District | | | | 1900-01-01 |
| CAMSD | Camarillo Sanitation District | Mike Viani | Camarillo | | 2012-06-05 |
| CAMPBELL | Campbell Soup Company Central Environmental Lab | | | | 2017-06-05 |
| CAMROSA | Camrosa Water District Laboratory | | | | 2017-06-05 |
| CANONIE | Canonie Environmental Services Lab | | | | 2017-06-05 |
| CAPCO | Capco Analytical Services, Inc. | | | | 2011-10-31 |
| CapeFear | Cape Fear Analytical | | | | 2020-03-27 |
| Cardno | Cardno | Chris Donley | Sacramento | chris.donley@cardno.com | 2015-01-26 |
| CarlsbadCity | Carlsbad City | | | | 2014-07-02 |
| CASC_Eng | CASC Engineering | Michael Kolbenschlag | Burbank | | 2014-07-09 |
| CMWD | Casitas Municipal Water District | | | | 2017-06-05 |
| CATE | Cate School | Jenna Driscoll | Santa Barbara | jennad@sbck.org | 2017-01-18 |
| CWD | Cawelo Water District | David Hampton | Bakersfield | dhampton@cawelowd.org | 2014-07-09 |
| CDMS | CDM Smith | Nola Mitchell | Truckee | mitchellna@cdmsmith.com | 2014-04-10 |
| CEIMIC | CEIMIC Corporation | | Narragansett | | 2012-08-30 |
| CELA | CEL Analytical, Inc | Yeagie Dearborn | San Francisco | Yeggie@celanalytical.com | 2014-02-10 |
| CCID | Central California Irrigation District | | | | 2026-05-08 |
| CCAMP | Central Coast Ambient Monitoring Program | Karen Worcester | San Luis Obispo | Kworcester@waterboards.ca.gov | 2011-10-25 |
| CCAL | Central Coast Analytical Lab, Santa Barbara | | | | 2017-06-05 |
| CCLEAN | Central Coast Long Term Environmental Assessment Network | | | | 2026-06-16 |
| CCSE | Central Coast Salmon Enhancement | Steph Wald | Arroyo Grande | larissa.clarke@ccc.ca.gov | 2014-06-09 |
| CCWC | Central Coast Water Conservancy (CCWC) | Aleksandra Wydzga | | aleks@centralcoastsalmon.com | 2018-05-10 |
| CCWQP | Central Coast Water Quality Preservation, Inc. | Sarah Lopez, Technical Program Manager | Watsonville | sgreene@ccwqp.org | 2012-10-12 |
| CCWG-MLML | Central Coast Wetlands Group at Moss Landing Marine Labs | Ross Clark | Moss Landing | rclark@mlml.calstate.edu | 2014-09-03 |
| CCCSD | Central Contra Costa Sanitary District | Tri Nguyen | Martinez | tnguyen@centralsan.dst.ca.us | 2007-12-21 |
| CSERC | Central Sierra Environmental Resource Center | Meg Layhee | Twain Harte | megl@cserc.org | 2017-02-28 |
| CERCO | Cerco Analytical, Inc. | | | | 2017-06-05 |
| CERES | Ceres Analytical Laboratory | | El Dorado Hills | jhedin@ceres-lab.com | 2024-08-29 |
| CERT | Certified Testing | | | | 2017-06-05 |
| CH2MHILL | CH2M HILL | | Sacramento | | 2009-09-24 |
| CINMS | Channel Islands National Marine Sanctuary | | | | 2013-04-03 |
| CINC | Channel Islands Neighborhood Council | Karin Wisenbaker | | karin@aquaticbioassay.com | 2022-01-13 |
| CHEMANAL | Chemanal | | | | 2017-06-05 |
| CHEMWEST | Chemwest Analytical Laboratories, Inc. | | | | 2017-06-05 |
| CBL | Chesapeake Biological Laboratories | Jerry Frank | Solomons | frank@umces.edu | 2017-03-16 |
| CPCC | Chevron Phillips Chemical Company | | | | 2017-06-28 |
| CIWQS 481638 | CHEVRON USA INC | | | | 1900-01-01 |
| CUPC | Chevron USA Products Company | | | | 2013-04-03 |
| CIWQS 8451 | Chico City | | | | 1900-01-01 |
| CHROMALAB | Chromalab, Inc. | | | | 2017-06-05 |
| CIBA-GEIGY | Ciba-Geigy | | | | 2017-06-05 |
| CCSF | City and County of San Francisco | Anthony Rattonetti | San Francisco | trattone@sfwater.org | 2007-12-21 |
| CCSF-MWQDL | City and County of San Francisco - Millbrae WQ Division Lab | | Millbrae | | 2026-01-05 |
| CCSF-OBL | City and County of San Francisco - Oceanside Biology Lab | Michael G. Kellogg | San Francisco | mkellogg@sfwater.org | 2012-08-30 |
| CCSF-ORG | City and County of San Francisco - Organics Lab | David Fok | San Francisco | dfok@sfwater.org | 2012-08-30 |
| CCSF-SWQDL | City and County of San Francisco - Southeast WQ Division Lab | | San Francisco | | 2026-01-05 |
| CCRML | City of Carmel-By-The-Sea | | Carmel-By-The-Sea | | 2012-07-30 |
| CC | City of Chico | | | | 2018-03-31 |
| CCV | City of Chula Vista | Marisa Soriano | Chula Vista | msoriano@ci.chula-vista.ca.us | 2013-12-05 |
| CE | City of Encinitas | | | | 2013-10-29 |
| CES | City of Escondido | | | | 2016-02-18 |
| CLN | City of Laguna Niguel | Nancy Palmer | Laguna Niguel | | 2013-06-03 |
| CLBHHS | City of Long Beach Health and Human Services | Hans Tritten | Long Beach | | 2012-05-07 |
| LBCPW | City of Long Beach Public Works | | | | 2018-06-14 |
| LABOSWPD | City of Los Angeles, Bureau of Sanitation, Watershed Protection | | | | 2017-03-24 |
| LAC_DPW_BSS | City of Los Angeles, Department of Public Works, Bureau of Street Services | Nazario Sauceda | Los Angeles | bss.boss@lacity.org | 2018-06-22 |
| CLAEMD | City of Los Angeles, Environmental Monitoring Division | Curtis Cash | Playa del Rey | curtis.cash@lacity.org | 2012-06-27 |
| OS | City of Oceanside | Unknown | Oceanside | | 2012-05-07 |
| COXLSP | City of Oxnard Laboratory Services Program | City Hall | Oxnard | | 2012-05-07 |
| PRC | City of Paso Robles | | Paso Robles | | 2017-05-08 |
| CPL | City of Porterville Laboratory | | Porterville | engbldg@ci.porterville.ca.us | 2012-08-02 |
| CSD | City of San Diego | | | | 2012-05-07 |
| EMTS | City of San Diego Environmental Monitoring & Technical Services Laboratory | | | | 2016-11-18 |
| CSD_TSW | City of San Diego Transportation & Storm Water Department | | | | 2020-03-27 |
| CSJ-ESD-WSP-SM | City of San Jose - Environmental Services Department - Watershed Protection Division - Stormwater Management | Carol Boland | San Jose | Carol.Boland@sanjoseca.gov | 2016-07-11 |
| CSJ | City of San Jose Water Pollution Control Plant | Environmental Services | San Jose | esdwebmaster@sanjoseca.gov | 2007-12-21 |
| CSC | City of Santa Cruz | | Santa Cruz | | 2019-10-09 |
| CSM | City of Santa Monica | Rick Valte | Santa Monica | rick.valte@smgov.net | 2012-11-20 |
| CSR | City of Santa Rosa | Heaven Moore | Santa Rosa | hmoore@srcity.org | 2017-06-28 |
| CS | City of Santee | Helen Davies | Santee | hdavies@ci.santee.ca.us | 2013-05-03 |
| COSVWWTPL | City of Simi Valley WWTP laboratory | | | | 2019-06-04 |
| CTDPW | City of Torrance Department of Public Works | | Torrance | | 2018-04-19 |
| Vallejo | City of Vallejo | | | | 2012-08-30 |
| CV | City of Ventura | | | | 2013-04-03 |
| WC | City of Watsonville | Emma Pickering | Watsonville | emma.pickering@cityofwatsonville.org | 2016-06-15 |
| WC_Lab | City of Watsonville Lab | | Watsonville | | 2016-07-28 |
| CYC | City of Yuba City Water/Wastewater Laboratory | Michael L. Paulucci | Yuba City | | 2014-01-16 |
| CWE | Civil, Water, Environmental | Gerald Greene | Fullerton | ggreene@cwecorp.com | 2013-09-30 |
| CKY | CKY Inc. Analytical Laboratories | | | | 2017-06-05 |
| CKY_PT | CKY Inc. Analytical Laboratories, Pleasanton and Torrence | | | | 2017-06-05 |
| CLARKSON | Clarkson Laboratory and Supply Inc. | | | | 2017-06-05 |
| CLAYTON | Clayton Environmental | | | | 2017-06-05 |
| CIWQS 8809 | Clear Creek CSD | | | | 1900-01-01 |
| CLERC | Clear Lake Environmental Research Center | | | | 2021-09-29 |
| CLSB | Clinical Laboratory of San Bernardino | | | | 2016-06-03 |
| CIWQS 8865 | Clovis City | | | | 1900-01-01 |
| CMANAL | CM Analytical, Inc. | | | | 2017-06-05 |
| CIWQS 8901 | Coachella SD | | | | 1900-01-01 |
| CVILC | Coachella Valley Irrigated Lands Coalition | | | contact.us@cvilc.ag | 2021-08-03 |
| CVWD | Coachella Valley Water District | | Coachella | | 2021-08-03 |
| CIWQS 8902 | Coachella Valley WD | | | | 1900-01-01 |
| CURES | Coalition for Urban/Rural Environmental Stewardship | Parry Klassen | | pklassen@unwiredbb.com | 2013-04-29 |
| CCAS | Coast to Coast Analytical Specialists, Inc. | | Garland | info@ccaslab.com | 2012-05-07 |
| CCR | Coastal Conservation and Research | James Oakden | Moss Landing | joakden@gmail.com | 2015-01-28 |
| CSLRCD | Coastal San Luis Resource Conservation District | | | | 2018-01-12 |
| CWC | Coastal Watershed Council | Debie Chirco-Macdonald | Santa Cruz | djchirco@coastal-watershed.org | 2012-11-28 |
| CIWQS 9009 | Colfax City | | | | 1900-01-01 |
| CIWQS 9014 | College of the Redwoods | | | | 1900-01-01 |
| CIWQS 9021 | Collins Pine Company Chester | | | | 1900-01-01 |
| CAS | Columbia Analytical Services | | | | 2011-05-12 |
| CIWQS 9073 | Colusa City | | | | 1900-01-01 |
| ColusaCounty | Colusa County | | | | 2017-06-08 |
| Condor | Condor Earth Technologies | Micheline Kipf | Stockton | mkipf@condorearth.com | 2019-12-19 |
| CFR | Conservation Farms and Ranches, Inc. | Emily Wells | Thornton | emily.wells@cfrstaten.com | 2021-07-02 |
| CCCWP | Contra Costa Clean Water Program | Jamison Crosby | | jcros@pw.cccounty.us | 2012-08-30 |
| CCRCD | Contra Costa Resource Conservation District | | Concord | | 2018-10-03 |
| CCWDL | Contra Costa Water District Laboratory, Concord | | | | 2017-06-05 |
| CFEP | Controls for Environmental Pollution | | | | 2017-06-05 |
| CONVERSE | Converse Envirolab, Inc. | | | | 2017-06-05 |
| COOK | Cook Research Lab | | | | 2017-06-05 |
| CORE | Core Laboratories, Inc. | | | | 2017-06-05 |
| CIWQS 9406 | Corning City | | | | 1900-01-01 |
| CIWQS 524675 | Corona City DWP | | | | 1900-01-01 |
| CDMWTPL | Corona Del Mar Water Treatment Plant Laboratory | | | | 2017-06-28 |
| Ccity | Coronado City | | | | 2015-07-06 |
| CNR | Coronado Naval Reserve | Ewan Moffat | San Diego | | 2012-05-07 |
| CWH | Council for Watershed Health | Emily Daniels | | emily@watershedhealth.org | 2015-06-11 |
| DN | County of Del Norte Health and Human Care | Leon Perrault | Crescent City | | 2012-05-07 |
| CMaEHS | County of Marin Environmental Health Services | Robert Turner | San Rafel | | 2012-05-07 |
| CMeEHS | County of Mendocino Environmental Health | John Morley | Ukiah | | 2012-05-07 |
| MY | County of Monterey Department of Health Division of Environmental Health | Roger Beretti | Monterey | | 2012-05-07 |
| CSDDEH | County of San Diego Department of Environmental Health | Ewan Moffat | San Diego | | 2012-05-07 |
| CSHSEHD | County of Sonoma Health Services Environmental Health Division | Terry Macute | Santa Rosa | | 2012-05-07 |
| Cranmer | Cranmer Engineering Inc | | | | 2018-03-27 |
| CEI | Cranmer Enginering and Anaytical Laboratory | | Grass Valley | lab@cranmerengineeringinc.com | 2017-04-25 |
| CEL | Creek Environmental Laboratories, Inc. | Orval Osborne | San Luis Obispo | oosborne@fix.net | 2013-10-25 |
| CIWQS 9674 | Crescent City | | | | 1900-01-01 |
| CCWQL | Crescent City Water Quality Laboratory | | Crescent City | | 2018-07-25 |
| Cressey | Cressey and Associates | Scott Cressey | El Cerrito | | 2012-09-04 |
| CRGML | CRG Marine Laboratories, Inc. | Rich Gossett | Torrance | info@crgmarinelabs.com | 2007-09-01 |
| CIWQS 9704 | Crockett Cogeneration | | | | 1900-01-01 |
| CROSBY | Crosby Laboratories, Inc. | | | | 2017-06-05 |
| CIWQS 9780 | Crystal Creek Aggregate Inc | | | | 1900-01-01 |
| CSUF | CSU Fresno, Lab | | | | 2017-06-05 |
| CulverCity | Culver City | | | | 2024-05-03 |
| CATL | Curtis and Tompkins, Ltd | | Berkeley | | 2017-02-22 |
| DGSL | D.G. Slotton Laboratory | Darell G. Slotton | Davis | dgslotton@ucdavis.edu | 2026-06-26 |
| DPC | Dana Point City | | | | 2019-02-13 |
| DCE | Dancing Coyote Environmental | Julie Schneider Ljubenkov | Pauma Valley | jsl@artnatureeducation.com | 2015-11-16 |
| DataChem | DataChem Laboratories, Inc | | Salt Lake City | | 2011-04-07 |
| DAVI | Davi Laboratories Environmental Associates | | | | 2017-06-05 |
| CIWQS 12331 | Davis City | | | | 1900-01-01 |
| DEAN | Dean Laboratories, Norco | | | | 2017-06-05 |
| LABQA | default setting for lab generated QA samples | | | | 2007-09-01 |
| DEL | Del Mar Analytical | Patty Mata | Irvine | | 2017-05-25 |
| DELMAR | Del Mar Analytical, Colton | | | | 2017-06-05 |
| DelMarCity | Del Mar City | | | | 2014-07-02 |
| DelNorteCounty | Del Norte County | | | | 2017-06-08 |
| DDLV | Dellavalle Laboratory, Inc. | | Fresno | | 2009-02-19 |
| CIWQS 12599 | Delta Diablo Sanitation District | | | | 1900-01-01 |
| DeltaEnv | Delta Environmental Lab | Dr. Hossein Khosh Khoo | Benicia | deltahk1@sbcglobal.net | 2011-01-25 |
| DELTAKEEPER | Deltakeeper | | | | 2017-06-05 |
| DEL-TECH | Del-Tech Geotechnical Support Services | | | | 2010-12-03 |
| DFW | Department of Fish and Wildlife | | | | 2012-03-07 |
| DFW-BDD | Department of Fish and Wildlife - Bay Delta Division | | | | 2012-08-30 |
| DFW-Belden | Department of Fish and Wildlife Belden Office | | | | 2008-08-26 |
| DFW-LOSALA | Department of Fish and Wildlife Los Alamitos Office | | Los Alamitos | | 2010-08-13 |
| DFW-Portola | Department of Fish and Wildlife Portola Office | Amber Rossi | Portola | | 2008-11-07 |
| DFW-RED | Department of Fish and Wildlife Redding Office | | | | 2008-06-20 |
| DFW-SanDiego | Department of Fish and Wildlife San Diego Office | | | | 2013-03-04 |
| DFW-Weave | Department of Fish and Wildlife Weaverville Office | | | | 2011-08-19 |
| DFW-WestSac | Department of Fish and Wildlife West Sacramento Office | | West Sacramento | | 2025-06-24 |
| DFW-Yreka | Department of Fish and Wildlife Yreka Office | Caitlin Bean | Yreka | Caitlin.Bean@wildlife.ca.gov | 2022-02-22 |
| DFW-OSPR | Department of Fish and Wildlife-OSPR | | Sacramento | | 2016-01-14 |
| DWR | Department of Water Resources - Sacramento Office | | | | 2011-06-27 |
| DWR-BRYTE | Department of Water Resources Bryte Analytical Laboratory | | West Sacramento | | 2007-09-01 |
| DWR-CASTAIC | Department of Water Resources Castaic Analytical Laboratory | | | | 2017-06-05 |
| DWR-SCRO | Department of Water Resources, South Central Region Office | Abimael León | Fresno | aleoncar@water.ca.gov | 2013-08-29 |
| CIWQS 12837 | Dicalite Minerals Corp | | | | 1900-01-01 |
| Dionex | Dionex | | | | 2007-09-01 |
| D-Max | D-Max Engineering, Inc | John Quenzer | San Diego | jquenzer@dmaxinc.com | 2013-05-03 |
| CIWQS 13111 | Donner Summit Public Utilities District | | | | 1900-01-01 |
| CIWQS 13129 | Dos Cuadras Offshore Res. LLC | | | | 1900-01-01 |
| DOWAGRO | Dow Agrosciences Analytical Laboratory, Indianapolis | | | | 2017-06-05 |
| DOWCHEM | Dow Chemical USA, Western Division, Pittsburg | | | | 2017-06-05 |
| Risebrough | Dr. Robert Risebrough's laboratory at the UCB Richmond Field Station | Robert Risebrough | Berkeley | | 2007-12-21 |
| DCC | Dry Creek Conservancy | | | | 2010-10-19 |
| DU | Ducks Unlimited | | | | 2023-12-28 |
| DUDEK_Encinitas | Dudek Environmental and Engineering, Encinitas | Chris Oesch | Encinitas | coesch@dudek.com | 2021-01-14 |
| Duke | Duke University | P. Lee Ferguson | Durham | | 2019-10-31 |
| CIWQS 13316 | Dunsmuir City | | | | 1900-01-01 |
| DYNAMIC | Dynamic Consultants, Inc. | | | | 2017-06-05 |
| E&S | E&S Environmental Chemistry, Inc. | Todd McDonnell | Corvallis | todd.mcdonnell@esenvironmental.com | 2017-03-16 |
| ESJWQC | E. San Joaquin Water Quality Coalition | | | | 2017-06-05 |
| EagleLkGuard | Eagle Lake Guardians | Val Aubrey | Susanville | eaglelakeguardians@yahoo.com | 2019-01-14 |
| EALCORP | EAL Corporation Laboratory | | | | 2017-06-05 |
| EBB | East Bay Beautiful | | | | 2025-07-25 |
| EBMUD | East Bay Municipal Utility District | Francois Rodigari | Oakland | frodigar@ebmud.com | 2007-12-21 |
| CIWQS 14380 | EAST BAY MUNICIPAL UTILITY DISTRICT (Water Plants) | | | | 1900-01-01 |
| CIWQS 14384 | East Bay Reg Park Dist, Union SD & EBDA | | | | 1900-01-01 |
| EBRPD | East Bay Regional Park District | Matt Graul | Berkeley | | 2012-05-07 |
| ECCCHC | East Contra Costa County Habitat Conservancy | | | | 2019-09-27 |
| CIWQS 309528 | Eastern Municipal Water District | | | | 1900-01-01 |
| CIWQS 497348 | Eco Resources Inc | | | | 1900-01-01 |
| EcoAnalysts | EcoAnalysts, Inc | Gary Lester | Moscow | glester@ecoanalysts.com | 2014-09-04 |
| ESC | Ecological System Corporation (DOMINGUES WS) | | | | 2017-06-05 |
| ECORP-Rocklin | ECORP Consulting, Inc. Rocklin | | Rocklin | | 2017-08-04 |
| Edge_Corvallis | Edge Analytical Laboratories, Corvallis Laboratory | Sarah Miller | Corvallis | smiller@edgeanalytical.com | 2021-01-15 |
| CEC | El Cajon City | Jaime Campos | El Cajon | jcampos@cityofelcajon.us | 2013-12-03 |
| CIWQS 11077 | El Centro City | | | | 1900-01-01 |
| ElDoradoCounty | El Dorado County | | | | 2017-06-08 |
| CIWQS 14606 | El Dorado Irrigation District | | | | 1900-01-01 |
| EID | El Dorado Irrigation District Monitoring | Brian Deason | Placerville | bdeason@eid.org | 2016-11-28 |
| EDTU | El Dorado Trout Unlimited | | | | 2016-02-03 |
| eli | elimnology, Inc. | Eli Kersh, CLM | Point Richmond | ekersh@elimnology.com | 2020-09-17 |
| EGCDPW | Elk Grove City Dept of Public Works | | | | 2017-03-31 |
| EKR | Elk Valley Rancheria | | | | 2017-06-05 |
| ESNERR | Elkhorn Slough National Estuarine Research Reserve NOAA | John Haskins | | | 2014-06-10 |
| EMAX | EMAX Laboratories, Inc. | Jim Carter | Torrance | jcarter@emaxlabs.com | 2013-08-07 |
| EMCON | Emcon Associates | | | | 2017-06-05 |
| EMSL | EMSL Analytical, Inc. | | San Leandro | sanleandrolab@emsl.com | 2016-01-10 |
| EN | Encina | Ewan Moffat | Missing | | 2012-05-07 |
| EWA | Encina Wastewater Authority | Unknown | Carlsbad | | 2012-05-07 |
| ENGINSCI | Engineering Science | | | | 2017-06-05 |
| ENSECO-CAL | ENSECO-CAL, Orange County | | | | 2017-06-05 |
| ENSECO-CRL | ENSECO-CRL, Ventura | | | | 2017-06-05 |
| ENTHALPY | Enthalpy Analytical, Inc. | Ranjit Clarke | Orange | ranjit.clarke@enthalpy.com | 2016-03-01 |
| ENTHALPY_Berkeley | Enthalpy Analytical, Inc., Berkeley | | Berkeley | info@enthalpy.com | 2017-12-15 |
| ENTHALPY_EDH | Enthalpy Analytical, Inc., EDH | | El Dorado Hills | | 2023-11-27 |
| ENTHALPY_SanDiego | Enthalpy Analytical, Inc., San Diego | | San Diego | | 2024-02-16 |
| ENTHALPY_Wilmington | Enthalpy Analytical, Inc., Wilmington NC | | Wilmington | | 2021-06-30 |
| ENVIRO-CHEM | Enviro-Chem Laboratories, Inc. | | | | 2017-06-05 |
| EnviroMatrix | EnviroMatrix Analytical, Inc. | Dan Verdon | San Diego | | 2013-01-18 |
| EELI | Environmental Engineering Lab, Inc., San Diego | | | | 2017-06-05 |
| EHL | Environmental Health Labs | | | | 2017-06-05 |
| ELNI | Environmental Laboratory Network, Inc. | | San Diego | | 2022-04-22 |
| EMA | Environmental Micro Analysis | Don Peterson | Woodland | dpeterson@emalab.com | 2012-08-30 |
| EMASI | Environmental Monitoring and Services, Inc., Lab | | | | 2017-06-05 |
| EPARD | Environmental Protection Agency office of Research and Development | Robert J Ozretich | Corvallis | ozretich.robert@epa.gov | 2012-05-07 |
| UCD-EQL | Environmental Quality Laboratory | Peter Green | Davis | pggreen@ucdavis.edu | 2007-09-01 |
| ERGI | Environmental Research Group, Inc., Lab | | | | 2017-06-05 |
| ETS | Environmental Technical Service | Greg Conrad | Petaluma | | 2016-12-07 |
| EWG | Environmental Working Group | | | | 2012-08-30 |
| EOA | EOA, Inc. | | Oakland | | 2012-08-30 |
| EPA-R9 | EPA Region 9 Lab | Andy Lincoff | Richmond | | 2007-09-01 |
| CIWQS 14960 | Escondido City | | | | 1900-01-01 |
| ECWQL | Escondido City Water Quality Laboratory | | | | 2017-06-28 |
| EUREKA | Eureka Laboratories, Inc. | | | | 2017-06-05 |
| EuroFins | Eurofins | Magnolia Busse | Folsom | MagnoliaBusse@eurofinsus.com | 2015-08-17 |
| Eurofins_Tustin | Eurofins Built Environment Testing - Tustin | | Tustin | Env.Marketing@ET.EurofinsUS.com | 2024-09-09 |
| EuroCal_Irvine | Eurofins Calscience Irvine | | | | 2022-02-25 |
| Eurofins_Pomona | Eurofins Drinking Water Testing - Pomona | | Pomona | | 2025-01-23 |
| EEA | Eurofins Eaton Analytical, Inc. | | Monrovia | | 2016-08-19 |
| EFGS | Eurofins Frontier Global Sciences | Patrick Garcia-Strickland | Bothell | FrontierGS@EurofinsUS.com | 2017-11-22 |
| EXADMS | Exa Data & Mapping Services | | | | 2010-02-18 |
| ExcelChem | Excelchem Environmental Labs | John Somers | Rocklin | | 2012-02-01 |
| CIWQS 29010 | ExxonMobil Oil Corporation Torrance | | | | 1900-01-01 |
| CIWQS 15842 | Fairfield Suisun Sewer District | | | | 1900-01-01 |
| FSURMP | Fairfield Suisun Urban Runoff Management Program | Kevin Cullen | Fairfield | | 2013-01-24 |
| FARWEST | Far West Laboratories, Riverbank | | | | 2017-06-05 |
| FRCRM | Feather River Coordinated Resource Management Group | Leslie Mink | Quincy | plumasco@psln.com | 2012-07-19 |
| CIWQS 16050 | Ferndale City | | | | 1900-01-01 |
| FFIC | Firemans Fund Insurance Companies, Environmental Lab | | | | 2017-06-05 |
| FISHBIO | FISHBIO | | | | 2021-11-03 |
| FFC | Fishery Foundation of California | Trevor Kennedy | | tkennedy@fisheryfoundation.org | 2021-10-14 |
| FMC | FMC Lab | | | | 2017-06-05 |
| Fordham | Fordham University | | | | 2018-02-21 |
| FASI | Forensic Analytical Specialties, Inc. | | | | 2017-06-05 |
| CIWQS 16413 | Forestville Water District | | | | 1900-01-01 |
| FBC | Fort Bragg City | Teri Jo Barber | Fort Bragg | | 2016-06-06 |
| FBML | Fort Bragg Municipal Laboratory | | Fort Bragg | | 2016-07-05 |
| CIWQS 16475 | Fortuna City | | | | 1900-01-01 |
| CIWQS 16691 | Fresno City | | | | 1900-01-01 |
| FresnoCounty | Fresno County | | | | 2017-06-08 |
| FCPHL | Fresno County Public Health Laboratory | | | | 2017-06-05 |
| FoAR | Friends of Auburn Ravine | | | | 2025-03-18 |
| FoCC | Friends of Concord Creeks | | | | 2024-08-02 |
| FDC | Friends of Deer Creek | | Nevada City | | 2010-10-19 |
| FSRC | Friends of San Ramon Creek | | | | 1900-01-01 |
| FOSC | Friends of Sausal Creek | | Oakland | coordinator@sausalcreek.org | 1900-01-01 |
| Frog | Frog Environmental | Frog Environmental | Carson | Ag@frogenv.com | 2020-05-20 |
| FAL | Frontier Analytical Laboratory | | El Dorado Hills | | 2018-02-13 |
| FGS | Frontier Geosciences, Inc. | Dustin Leen | Seattle | dustinl@frontiergeosciences.com | 2007-09-01 |
| FGLE | Fruit Growers Lab (FGL Environmental) | | St Santa Paula | http://www.fglinc.com/ | 2008-01-01 |
| FGLE-Stockton | Fruit Growers Lab (FGL Environmental) Stockton | | Stockton | | 2023-10-31 |
| CIWQS 17625 | Galt City | | | | 1900-01-01 |
| GANDA | Garcia and Associates | Ian Chan | Tahoe City | iananthonychan@aol.com | 2016-11-23 |
| GCAL | Garratt-Callahan Analytical Laboratory | | | | 2017-06-05 |
| GWMA | Gateway Water Management Authority | | | | 2017-07-13 |
| GEI | GEI Consultants, Inc. | Ashley Ficke | Denver | aficke@geiconsultants.com | 2019-03-14 |
| GEI-Carlsbad | GEI Consultants, Inc. - Carlsbad | | Carlsbad | | 2025-02-19 |
| GEL | GEL Laboratories | | | | 2022-02-25 |
| CIWQS 31242 | General Dynamics National Steel & Shipbuilding Co (NASSCO) | | | | 1900-01-01 |
| CIWQS 17824 | General Electric Co | | | | 1900-01-01 |
| GEOANAL | Geoanalytical Laboratories, Inc. | | | | 2017-06-05 |
| GERG | Geochemical and Environmental Research Group | Jose L.Sericano | College Station | jose@gerg.tamu.edu | 2007-12-21 |
| Geocon_RC | Geocon Consultants, Inc. - Rancho Cordova Office | | Rancho Cordova | fordyce@geoconinc.com | 2025-08-27 |
| GEOMONITOR | Geo-Monitor, Inc. | | | | 2017-06-05 |
| GMU-AEL | George Mason University - Algal Ecology Lab | Rosalina Christova | Fairfax | rchris13@gmu.edu | 2025-05-28 |
| GCSU | Georgia College and State University | | | | 2018-02-21 |
| GC | Geosyntec Consultants | | Huntington Beach | | 2014-07-15 |
| Geosyntec_Sac | Geosyntec Consultants, Sacramento | | | | 2021-06-25 |
| GlennCounty | Glenn County | | | | 2017-06-08 |
| GGC-Canoga | Global Geochemical Corporation, Canoga Park | | | | 2017-06-05 |
| GRRCD | Gold Ridge RDC | Sierra Cantor | | sierra@goldridgercd.org | 2016-11-01 |
| GGNRA | Golden Gate National Recreation Area | | | | 2022-04-14 |
| GOLDPL | Golden Pacific Laboratories | | | | 2017-06-05 |
| Golder | Golder | | | | 2019-02-21 |
| CIWQS 18325 | GOLETA SD | | | | 1900-01-01 |
| GLC | Goose Lake Coalition | Herb Jasper | New Pine Creek | bry.jasper@oregonstate.edu | 2009-09-24 |
| GPL | GPL Laboratories Lllp | | Gaithersgurg | | 2012-05-07 |
| GMA | Graham Matthews and Associates | Graham Matthews | Weaverville | | 2013-03-28 |
| CIWQS 19392 | Granite Rock Co | | | | 1900-01-01 |
| CIWQS 18512 | Grass Valley City | | | | 1900-01-01 |
| GBP | Grassland Bypass Project | Chris Linneman | Hanford | linneman@summerseng.com | 2018-01-16 |
| GrassrootsEcology | Grassroots Ecology | Jeremy Merckling | Palo Alto | jeremy@grassrootsecology.org | 2018-07-02 |
| GBOC | Grassy Bar Oyster Company | George Trevelyan | Morro Bay | gboysterco@gmail.com | 2015-06-02 |
| GHWRMC-1415 | Greater Harbor Waters Regional Monitoring Coalition 2014/15 | | Long Beach | anthony.arevalo@longbeach.gov | 2015-12-03 |
| GHWRMC-1516 | Greater Harbor Waters Regional Monitoring Coalition 2015/16 | | Long Beach | anthony.arevalo@longbeach.gov | 2016-11-16 |
| GHWRMC-1617 | Greater Harbor Waters Regional Monitoring Coalition 2016/17 | | Long Beach | anthony.arevalo@longbeach.gov | 2017-11-22 |
| GHWRMC-1718 | Greater Harbor Waters Regional Monitoring Coalition 2017/18 | James Vernon | Long Beach | | 2018-11-27 |
| GHWRMC-1819 | Greater Harbor Waters Regional Monitoring Coalition 2018/19 | | | | 2019-11-09 |
| GHWRMC-1920 | Greater Harbor Waters Regional Monitoring Coalition 2019/20 | James Vernon | Long Beach | james.vernon@polb.com | 2020-12-18 |
| GVLR | Green Valley Lake Recreation | | | | 2023-11-06 |
| GWL | Green Water Laboratories | Mark Aubel | Palatka | markaubel@greenwaterlab.com | 2017-03-16 |
| CIWQS 18681 | Grizzly Lake Resort Imp Dist | | | | 1900-01-01 |
| GTEL | GTEL Environmental Laboratories, Inc. | | | | 2017-06-05 |
| HGPRATT | H.G. Pratt Company | | | | 2017-06-05 |
| HPUL | Habematolel Pomo of Upper Lake | Christina Harrison | | charrison@hpultribe-nsn.gov | 1900-01-01 |
| CIWQS 523382 | Hargis & Associates, Inc. | | | | 1900-01-01 |
| HAWKSLEY | Hawksley Laboratory | | | | 2017-06-05 |
| HCWPCFL | Hayward City Water Pollution Control Facility Laboratory | | | | 2017-06-05 |
| HML | Hazardous Materials Laboratory | | | | 2012-08-30 |
| HDR-SAC | HDR-Sacramento | | | | 2019-01-23 |
| CIWQS 20025 | Healdsburg City | | | | 1900-01-01 |
| HDCSMEH | Health Department County of San Mateo Environmental Health | Greg Smith | Redwood City | | 2012-05-07 |
| CIWQS 20060 | Heber PUD | | | | 1900-01-01 |
| HWDLWTP | Helix Water District R.M. Levy Water Treatment Plant | | | | 2017-06-05 |
| HENRICI | Henrici Water Laboratory, Quincy | | | | 2017-06-05 |
| CIWQS 20185 | HERITAGE RANCH CSD | | | | 1900-01-01 |
| HPEL | Hewlett-Packard Environmental Lab | | | | 2017-06-05 |
| HSWL | High Sierra Water Laboratory | Mark Palmer | Truckee | hswaterlab@aol.com | 2007-09-01 |
| CIWQS 20513 | Holtville City | | | | 1900-01-01 |
| CIWQS 21348 | Honeywell International Inc. | | | | 1900-01-01 |
| Hoopa-Tribe | Hoopa Tribe | Louisa McCovey | Hoopa | louisadebrose@gmail.com | 2012-04-20 |
| HBPIT | Hopland Band Of Pomo Indians Tribal EPA | | | | 2017-06-08 |
| HORNKOHL | Hornkohl Laboratories, Inc. | | | | 2017-06-05 |
| HI | Houston Industries, Inc. | | | | 2013-04-03 |
| HDL-SanJose | Hull Development Lab, Inc., San Jose | | | | 2017-06-05 |
| HumboldtCounty | Humboldt County | | | | 2017-06-08 |
| HCDEH | Humboldt County Division of Environmental Health | | | | 2019-07-15 |
| HCHHSDD | Humboldt County Health and Human Services Department Division of Environmental Health | Harriet Hill | Eureka | | 2012-05-07 |
| HSU-SL | Humboldt State University Department of Biological Sciences Shaunghnessy Lab | Dr. Frank J. Shaughnessy | | fjs3@humboldt.edu | 2013-09-26 |
| HW | Humboldt Waterkeeper | | Arcata | | 2025-07-29 |
| HFI | HydroFocus, Inc. | Steve Deverel | Davis | sdeverel@hydrofocus.com | 2021-07-02 |
| Hydrozoology | Hydrozoology | Wayne Fields | Newcastle | | 2019-05-24 |
| ICF-Los Angeles | ICF Los Angeles | | Los Angeles | | 2019-06-10 |
| ICF-Sacramento | ICF Sacramento | Jeff Peters | Sacramento | jeff.peters@icf.com | 2017-08-04 |
| ICF-San Diego | ICF San Diego | | San Diego | | 2017-09-07 |
| ICRI | I-Chem Research, Inc. | | | | 2017-06-05 |
| IEH | IEH Aquatic Research | | Seattle | | 2016-10-12 |
| IBCity | Imperial Beach City | | | | 2015-04-24 |
| CIWQS 21588 | Imperial CCD | | | | 1900-01-01 |
| CIWQS 21610 | Imperial City | | | | 1900-01-01 |
| ImperialCounty | Imperial County | | | | 2017-06-08 |
| CIWQS 21597 | Imperial ID | | | | 1900-01-01 |
| IID | Imperial Irrigation District | | Imperial | | 2022-12-08 |
| IVILC | Imperial Valley Irrigated Lands Coalition | | El Centro | info@icfb.net | 2022-12-08 |
| CIWQS 21650 | Indian Springs School District | | | | 1900-01-01 |
| IVCSD | Indian Valley Community Services District | | | | 2025-01-07 |
| IEc | Industrial Economics, Inc | Mindaugas Sereiva | Cambridge | msereiva@indecon.com | 2015-01-28 |
| IMTL | Industrial Marine Testing Lab, Inc. | | | | 2017-06-05 |
| CIWQS 147335 | Inland Empire Utilities Agency | | | | 1900-01-01 |
| ICARE | Institute for Conservation, Advocacy, Research, and Education (ICARE) | Chris Malan | Napa | | 2017-05-17 |
| Integral | Integral Consulting Inc. | | Seattle | | 2019-05-02 |
| IERS | Integrated Environmental Restoration Services | | | | 2010-02-11 |
| ITIS | Integrated Taxonomic Information System | | | | 2013-05-13 |
| InyoCounty | Inyo County | | | | 2017-06-08 |
| ICEHD | Inyo County Environmental Health Department | | | | 2023-11-01 |
| ICEHS | Inyo County Environmental Health Services Water Lab | | | | 2019-04-03 |
| CIWQS 21868 | Ironhouse Sanitary District | | | | 1900-01-01 |
| CIWQS 499770 | Irvine Ranch Water District | | | | 1900-01-01 |
| CIWQS 21509 | I'SOT Inc | | | | 1900-01-01 |
| ITCORP | IT Corporation Lab | | | | 2017-06-05 |
| CIWQS 22475 | J.F. Enterprises | | | | 1900-01-01 |
| CIWQS 22556 | Jackson City | | | | 1900-01-01 |
| JACOBS | Jacobs Lab | | | | 2017-06-05 |
| JMMCE | James M. Montgomery, Consulting Engineers, Inc., Lab | | | | 2017-06-05 |
| JPL | Jet Propulsion Laboratory | | | | 2013-04-03 |
| CIWQS 358762 | JF Shea Company Inc | | | | 1900-01-01 |
| JKBS | JK BioScience | | Rancho Dominguez | | 2025-06-11 |
| JLAS | JL Analytical Services, Inc. | | | | 2017-06-05 |
| JLHA | John L Hunter and Associates | Michelle Kim | Buena Park | mkim@jha.net | 2016-06-03 |
| JLC | Jon Lee Consulting | Jon Lee | Eureka | jlee@humboldt1.com | 2016-12-21 |
| JLLCV | June Lake Loop Citizen Volunteers | | | | 2023-07-12 |
| Karuk-Tribe | Karuk Tribe | Susan Fricke | Orleans | sfricke@karuk.us | 2017-03-16 |
| KBWQA | Kaweah Basin Water Quality Association | Donald Ikemiya | Visalia | dikemiya@ppeng.com | 2014-07-09 |
| Kaweah SW | Kaweah River Sub-Watershed | | | | 2011-03-24 |
| KTB | Keep Taho Blue | | South Lake Tahoe | | 2018-05-03 |
| KJC | Kennedy/Jenks/Chilton | | | | 2017-06-05 |
| KernCounty | Kern County | | | | 2017-06-08 |
| KCDPH | Kern County Dept of Public Health | | | | 2017-06-05 |
| KCWA-WQL | Kern County Water Agency, Water Quality Laboratory | | | | 2017-06-05 |
| Kern SW | Kern River Sub-Watershed | | | | 2011-03-24 |
| KERNRWCA | Kern River Watershed Coalition Authority | Nicole Bell | Bakersfield | admin@krwca.org | 2014-07-09 |
| KIFF | KIFF Analytical | | Davis | | 2011-11-28 |
| CIWQS 24287 | Kinder Morgan Energy Partners LP | | | | 1900-01-01 |
| KCEL | King County Environmental Laboratory | | | | 2017-05-23 |
| KingsCounty | Kings County | | | | 2017-06-08 |
| KRCD | Kings River Conservation District | | Fresno | | 2008-01-01 |
| Kings SW | Kings River Sub-Watershed | | | | 2011-03-24 |
| KINGSRWCA | Kings River Watershed Coalition Authority | Eric Athorp | Fresno | eathorp@krcd.org | 2014-07-09 |
| KEI | Kinnetic Environmental, Inc. | | | | 2023-04-10 |
| Kinnetic | Kinnetic Laboratories, Inc. | Robert Shelquist, Reg. Manager | Carlsbad | rshelquist@kinneticlabs.com | 2012-05-31 |
| KLI-Santa Cruz | Kinnetic Laboratories, Inc. Santa Cruz Office | | | | 2012-11-05 |
| KBMP | Klamath Basin Monitoring Program | Randy Turner | McKinleyville | randyt@sfei.org | 2016-10-14 |
| KBRT | Klamath Basin Rangeland Trust | Carolyn Doehring | Klamath Falls | cdoehring@kbrt.org | 2012-04-20 |
| Klamath-Tribes | Klamath Tribes | Kris Fischer | Chiloquin | fischerkris@msn.com | 2012-04-20 |
| KTNRD | Klamath Tribes Natural Resource Department | Chantell Royer-Krider | | mpc@kbmp.net | 2013-05-20 |
| KWP | Klamath Watershed Partnership | Nathan Jackson | Klamath Falls | njackson@klamathpartnership.org | 2012-04-20 |
| Kleinfelder | Kleinfelder | | Sacramento | | 2009-09-24 |
| CIWQS 24377 | Klondike California Mining Corp | | | | 1900-01-01 |
| KPI | KPrime, Inc. | | Santa Rosa | | 2019-09-26 |
| LMCity | La Mesa City | | | | 2015-04-24 |
| LASAN | LA Sanitation and Environment | | | | 2024-03-05 |
| LDSRF | Laguna de Santa Rosa Foundation | Hattie Brown | Santa Rosa | hattie@lagunafoundation.org | 2012-08-30 |
| LEL | Laguna Environmental Laboratory | | Santa Rosa | | 2017-09-05 |
| LAKEARROWHEAD | Lake Arrowhead Community Services District | | | | 2017-06-05 |
| LakeCounty | Lake County | | | | 2017-06-08 |
| LCWRD | Lake County Water Resources Department | | | | 2011-06-27 |
| LEC | Lake Elsinor City | | | | 2019-07-26 |
| LESJWA | Lake Elsinore and San Jacinto Watershed Authority | Rich Whetsel | Riverside | | 2017-04-14 |
| LMI | Lake Merritt Institute | | Oakland | | 2019-02-20 |
| Laragen | Laragen Sequencing, Inc. | | Culver City | info@laragen.com | 2019-08-30 |
| LWA | Larry Walker Associates | Michael Marson | Ventura | michaelm@lwa.com | 2012-05-22 |
| CIWQS 25562 | Las Gallinas Valley Sanitary District | | | | 1900-01-01 |
| LVMWD | Las Virgenes Muncipal Water District | | | | 2018-09-22 |
| CIWQS 26657 | Las Virgenes MWD | | | | 1900-01-01 |
| LassenCounty | Lassen County | | | | 2017-06-08 |
| LLNL | Lawrence Livermore National Laboratory | | | | 2017-06-05 |
| LTSLT | League to Save Lake Tahoe | Emily Frey | South Lake Tahoe | emily@keeptahoeblue.org | 2020-11-16 |
| LEERO | Lee & Ro Environmental Laboratories | | | | 2017-06-05 |
| LCCC | Lehigh Cement Co Cupertino | | | | 2021-03-03 |
| CIWQS 25746 | Lehigh Southwest Cement Co Redding | | | | 1900-01-01 |
| LGCity | Lemon Grove City | | | | 2015-07-06 |
| LFE | LFE Environmental Analysis Lab | | | | 2017-06-05 |
| CIWQS 25963 | Lincoln Center Env Remed Trust | | | | 1900-01-01 |
| CIWQS 25974 | Lincoln City | | | | 1900-01-01 |
| CIWQS 25978 | Linda Cnty Water District | | | | 1900-01-01 |
| CIWQS 26056 | Live Oak City | | | | 1900-01-01 |
| CIWQS 11100 | Lodi City | | | | 1900-01-01 |
| CIWQS 26133 | Loleta CSD | | | | 1900-01-01 |
| CIWQS 26142 | Lompoc City | | | | 1900-01-01 |
| LCWTP | Lompoc City Water Treatment Plant | | | | 2017-06-28 |
| LongBeachCity | Long Beach City | | | | 2016-02-23 |
| LBCSMD | Long Beach City Stormwater Management Division | Anthony Arevalo | Long Beach | anthony.arevalo@longbeach.gov | 2015-12-03 |
| LBCWTD | Long Beach City Water Treatment Department | | | | 2017-06-28 |
| CIWQS 27069 | Long Beach Generation LLC | | | | 1900-01-01 |
| CIWQS 25146 | Los Angeles City Bureau of Sanitation | | | | 1900-01-01 |
| LACityDWP | Los Angeles City Dept of Water and Power Environmental Lab | | | | 2017-06-05 |
| CIWQS 25175 | Los Angeles Cnty SD | | | | 1900-01-01 |
| LosAngelesCounty | Los Angeles County | | | | 2017-06-08 |
| LACDBH | Los Angeles County Department of Beaches and Harbors | | | | 2013-04-03 |
| DH | Los Angeles County Department of Health Services | Malay Trivedi | Baldwin Park | | 2012-05-07 |
| LACDPR | Los Angeles County Department of Parks and Recreation | | | | 2025-05-02 |
| LACDPW | Los Angeles County Department of Power and Water | | | | 2013-10-29 |
| LACDPH | Los Angeles County Department of Public Health | | | | 2025-04-17 |
| LACDPW-WMD | Los Angeles County Department of Public Works | | Alhambra | | 2016-07-28 |
| LACEH | Los Angeles County Environmental Health | Becky Valenti | Baldwin Park | | 2012-05-07 |
| LACETL | Los Angeles County Environmental Toxicology Laboratory | | | | 2017-06-05 |
| LACSD | Los Angeles County Sanitation Districts | Kathy | Whittier | | 2012-05-07 |
| LMU | Loyola Marymount University | | | | 2012-05-16 |
| LSCE | Luhdorff & Scalmanini, Consulting Engineers | | Woodland | | 2022-06-16 |
| LU_FL | LuminUltra, Florida | | Miami Lakes | | 2022-09-01 |
| Lunkefer | Lunkefer | | | | 2012-03-29 |
| MACS | MACS Lab, Inc. | | | | 2017-06-05 |
| MaderaCounty | Madera County | | | | 2017-06-08 |
| CIWQS 44013 | Magic Mountain, LLC (Former Six Flags Theme Parks, Inc) | | | | 1900-01-01 |
| CIWQS 27641 | Malaga CWD | | | | 1900-01-01 |
| MalC | Malibu City | Jennifer Brown | Malibu | jbrown@malibucity.org | 2014-04-22 |
| CIWQS 27706 | Manteca City | | | | 1900-01-01 |
| MAN_City | Manteca, City of | | Manteca | | 2025-09-30 |
| MarinCounty | Marin County | | | | 2017-06-08 |
| MCSTOPPP | Marin County Stormwater Pollution Prevention Program | | | | 2016-08-18 |
| MMWD | Marin Municipal Water District | | | | 2017-06-05 |
| MCWDL | Marina Coast Water District Laboratory | | | | 2017-06-05 |
| MCCP | Marine Corps Base Camp Pendleton | Unknown | Camp Pendelton | | 2012-05-07 |
| MMC | Marine Mammal Center | Denise Greig | Sausalito | | 2014-10-30 |
| MMVM | Marine Microbiology and Vector Management | | | | 2016-06-10 |
| MPSL-DFW | Marine Pollution Studies Laboratory-DFW | Wesley Heim | Moss Landing | wheim@mlml.calstate.edu | 2018-02-12 |
| MPSL-MLML | Marine Pollution Studies Laboratory-MLML | Rusty Fairey | Moss Landing | fairey@mlml.calstate.edu | 2007-09-01 |
| MARRESSPEC | Marine Research Specialists | | Ventura | | 2017-06-05 |
| MTS | Marine Taxonomic Services | | | | 2022-10-12 |
| MariposaCounty | Mariposa County | | | | 2017-06-08 |
| CIWQS 27814 | MARIPOSA PUD | | | | 1900-01-01 |
| MTH | Mark Twain Hospital | | | | 2017-06-05 |
| MCWTP | Martinez City Water Treatment Plant | | | | 2017-06-05 |
| MAL | Maxxam Analytics | | Mississauga | | 2014-07-15 |
| MBC | MBC Aquatic Sciences | | | | 2019-04-02 |
| CIWQS 28203 | McCabe USD | | | | 1900-01-01 |
| MCA | McCampbell Analytical Inc. | | Pittsburg | | 2011-09-09 |
| MEI | McCord Environmental, Inc. | Stephen McCord | Davis | sam@mccenv.com | 2017-09-15 |
| MSLI | McDonald-Stevens Lab Inc. | | | | 2017-06-05 |
| MESL | McKesson Environmental Service Lab | | | | 2017-06-05 |
| CIWQS 28265 | McKinleyville CSD | | | | 1900-01-01 |
| MHEEC | McLaren/Hart Environmental Engineering Corporation | | | | 2017-06-05 |
| MEC | MEC Analytical Systems | Susie Watts | Carlsbad | Susie.Watts@WestonSolutions.com | 2007-09-01 |
| Medallion | Medallion Labs | | Minneapolis | info@medlabs.com | 2014-11-04 |
| MendocinoCounty | Mendocino County | | | | 2017-06-08 |
| CIWQS 28505 | Merced City | | | | 1900-01-01 |
| MCWWL | Merced City WasteWater Laboratory | | | | 2017-06-28 |
| MercedCounty | Merced County | | | | 2017-06-08 |
| MERID | Merced Irrigation District | Hicham ElTal | Merced | | 2009-09-24 |
| CIWQS 28528 | Meridian Gold Company | | | | 1900-01-01 |
| MERKELINC | Merkel and Associates Inc | Amanda K. Gonzales | San Diego | agonzales@merkelinc.com | 2021-01-29 |
| MWDSC | Metropolitan Water District of Southern California | | | | 2017-06-05 |
| MLJ-LLC | Michael L. Johnson, LLC | Michael Johnson | Davis | mjohnson@mlj-llc.com | 2007-09-01 |
| Michelson | Michelson Laboratories, Inc | | | | 2011-10-07 |
| Microbac-Arcata | Microbac Laboratories Arcata | | Arcata | Roxanne.Golich@microbac.com | 2024-03-13 |
| MKGSA | Mid-Kaweah Groundwater Sustainability Agency | | | | 2022-11-11 |
| MIDWAY | Midway Laboratory Inc. | | | | 2017-06-05 |
| MOE | Mikhail Ogawa Engineering | Mikhail Ogawa | Del Mar | | 2020-01-14 |
| CIWQS 28870 | Mining Remedial Recovery Co | | | | 1900-01-01 |
| MissionEnv | Mission Environmental | | San Diego | info@missionenv.com | 2026-04-01 |
| MISSION | Mission Laboratory, Gilroy | | | | 2017-06-05 |
| MLJEnvironmental | MLJ Environmental | Melissa Turner | Davis | mturner@mljenvironmental.com | 2018-10-11 |
| CIWQS 29046 | Modesto City | | | | 1900-01-01 |
| MODCSP | Modesto City Stormwater Program | | | | 2024-02-16 |
| MCU | Modesto City Utilities | David Felix | Modesto | dfelix@modestogov.com | 2016-03-30 |
| MCWQCL | Modesto City Water Quality Control Laboratory | | | | 2017-06-28 |
| MODID | Modesto Irrigation District | Walter Ward | Modesto | | 2009-09-24 |
| ModocCounty | Modoc County | | | | 2017-06-08 |
| CIWQS 29055 | Modoc Joint Unified School District | | | | 1900-01-01 |
| ModocRCD | Modoc Resource Conservation District | | | | 2020-01-10 |
| MONARCH | Monarch Laboratory Inc., Chico | | | | 2017-06-05 |
| MBAS | Monterey Bay Analytical Services | David Holland | Monterey | | 2013-01-04 |
| MBARI | Monterey Bay Aquarium Research Institute | | | | 2017-09-15 |
| MBARI-JL | Monterey Bay Aquarium Research Institute; Marine Chemistry Department Johnson Laboratory | Ken Johnson | Moss Landing | johnson@mbari.org | 2013-09-26 |
| MBNMS | Monterey Bay National Marine Sanctuary | Bridget Hoover | Monterey | Bridget.Hoover@noaa.gov | 2014-06-09 |
| MontereyCounty | Monterey County | | | | 2017-06-08 |
| MRWPCA | Monterey Regional Water Pollution Control Agency | | | | 2016-03-18 |
| MTA | Moore Twining Associates, Inc. | Maria Manuel | Fresno | mariam@mooretwining.com | 2012-09-13 |
| MBNEP | Morro Bay National Estuary Program | Thomas Stanford | | | 2013-12-19 |
| MBOC | Morro Bay Oyster Company | Neal Maloney | Morro Bay | neal@morrobayoysters.com | 2015-06-02 |
| MORSE | Morse Laboratories, Sacramento | | | | 2017-06-05 |
| MLML_Oakden | Moss Landing Marine Laboratories - Oakden Lab | Jim Oakden | Moss Landing | oakden@mlml.calstate.edu | 2012-08-30 |
| MLML-Coale | Moss Landing Marine Laboratories Coale Lab | Dr. Kenneth Coale | Moss Landing | Coale@mlml.calstate.edu | 2012-10-05 |
| MLML-RDC | Moss Landing Marine Laboratories Regional Data Center | Mark Pranger | Moss Landing | pranger@mlml.calstate.edu | 2012-04-20 |
| MLML-BL | Moss Landing Marine Laboratories-Benthic Lab | Peter Slattery | Moss Landing | pslattery@mlml.calstate.edu | 2007-09-01 |
| MLML-CO | Moss Landing Marine Laboratories-CO | Dr. Kenneth Cole | Moss Landing | | 2012-10-05 |
| MLML-EBL | Moss Landing Marine Laboratories-Environmental Biotechnology Lab | Holly Bowers | Moss Landing | | 2026-06-18 |
| MLML-GeoOc | Moss Landing Marine Laboratories-Geological Oceanography | Ivano W. Aiello | Moss Landing | iaiello@mlml.calstate.edu | 2012-08-30 |
| MLML-NutrientLab | Moss Landing Marine Laboratories-Nutrient Lab | Steven Cunningham | Moss Landing | | 2025-10-31 |
| MLML-TM | Moss Landing Marine Laboratories-Trace Metals Lab | Sara Tanner | Moss Landing | tanner@mlml.calstate.edu | 2007-09-01 |
| CIWQS 29366 | Mountain House CSD | | | | 1900-01-01 |
| MRCA | Mountains Recreation and Conservation Authority | Ana Straabe | Los Angeles | ana.straabe@mrca.ca.gov | 2018-06-26 |
| MRT | Mountains Restoration Trust | Kyle Troy | Calabasas | ktroy@mountainstrust.org | 2014-06-03 |
| CIWQS 29441 | Mt Lassen Trout Farms Inc | | | | 1900-01-01 |
| CIWQS 29446 | Mt Shasta City | | | | 1900-01-01 |
| CIWQS 29450 | MT. VIEW SANITARY DISTRICT | | | | 1900-01-01 |
| MULTITECH | Multi-Tech, Inc., Lab | | | | 2017-06-05 |
| MC | Murrieta City | | Murrieta | | 2018-01-30 |
| MWH | MWH Laboratories | James C. Hein | Monrovia | mwhlabs@mwhglobal.com | 2007-09-01 |
| NAL | Nachtmann Analytical Laboratory, Davis | | | | 2017-06-05 |
| NapaCounty | Napa County | | | | 2017-06-08 |
| NAPARCD | Napa County Resource Conservation District | | Napa | | 2009-10-14 |
| CIWQS 31164 | NAPA SANITATION DISTRICT | | | | 1900-01-01 |
| NAMC | National Aquatic Monitoring Center | Trip Armstrong | Logan | | 2023-02-16 |
| NCCity | National City | | | | 2015-04-24 |
| NOAA | National Oceanic and Atmospheric Administration | | Washington | | 2012-08-30 |
| NAUT | Nautilus Environmental | Steve Carlson | San Diego | stevec@nautilusenvironmental.com | 2007-09-01 |
| NIWC_Pacific | Naval Information Warfare Center Pacific | | | | 2022-04-14 |
| NELL | NEL Laboratories | Doug McCormack | Reno | dmccormack@nelabs.com | 2007-09-01 |
| NELSON | Nelson Lab | | | | 2017-06-05 |
| NWQAL | Nestle Waters Quality Assurance Laboratory | | | | 2017-06-05 |
| NETPACIFIC | Net Pacific, Inc. | | | | 2017-06-05 |
| CIWQS 31378 | Nevada City | | | | 1900-01-01 |
| NevadaCounty | Nevada County | | | | 2017-06-08 |
| CIWQS 31380 | Nevada CSD No 1 | | | | 1900-01-01 |
| NDEP | Nevada Division of Environmental Protection | Marianne Denton | Carson | dentonm@ndep.nv.gov | 2015-02-18 |
| NIDNAWTP | Nevada Irrigation District North Auburn Water Treatment Plant | | | | 2017-06-05 |
| NTCD | Nevada Tahoe Conservation District | Meghan Kelly | Zephyr Cove | info@ntcd.org | 2018-12-03 |
| CIWQS 31394 | NEW CENTURY BEVERAGE COMPANY | | | | 1900-01-01 |
| NewFields | NewFields | | | | 2020-10-22 |
| NL&FC | Newhall Land and Farming Company | | | | 2016-12-23 |
| CIWQS 400869 | Newhall Ranch Sanitation District | | | | 1900-01-01 |
| CIWQS 31531 | Niland SD | | | | 1900-01-01 |
| NOAACHHR | NOAA Center for Human Health Risk | | | | 2012-05-07 |
| NOAACOAST | NOAA Coastal Oceanographic Assessment Status and Trends | Gunnar Lauenstein, Ph.D. | Silver Spring | | 2012-05-07 |
| NBRWTP | North Bay Regional Water Treatment Plant | | | | 2017-06-05 |
| NCCWDL | North Coast County Water District Lab | | | | 2017-06-05 |
| NMWD | North Marin Water District | | | | 2017-06-05 |
| NSDCWMP | North San Diego County Watershed Monitoring Program | | | | 2019-10-23 |
| CIWQS 31673 | North San Mateo County Sanitation District | | | | 1900-01-01 |
| NSR | North State Resources, Inc. | Len Lindstrand III | Redding | lindstrand@nsrnet.com | 2015-04-09 |
| NEC | Northcoast Environment Center | | | | 2022-11-02 |
| NECWA | Northeastern California Water Association | Helen Albaugh | McArthur | halbaugh@hdo.net | 2009-12-22 |
| NAU | Northern Arizona University | Dean Blinn | | dean.blinn@nau.edu | 2007-09-01 |
| NCPA | Northern California Power Agency | | Murphys | benjamin.guy@ncpa.com | 2024-12-13 |
| NCNRCD | Northern California-Nevada Resource Conservation District | Todd Sloat | | tsloat@citlink.net | 2007-09-01 |
| NGEM | Northgate Environmental Management, Inc. | Dana R. Brown | Laguna | dana.brown@ngem.com | 2016-06-03 |
| CIWQS 46428 | Northrop Grumman Systems Corporation | | | | 1900-01-01 |
| NorthStar | NorthStar Engineering | | | | 2019-01-02 |
| NV5_Long Beach | NV5 Long Beach Office | Jacqueline McMillen | Long Beach | jacqueline.mcmillen@nv5.com | 2021-04-21 |
| NV5_Oceanside | NV5 Oceanside Office | Garth Engelhorn | Oceanside | garth.engelhorn@nv5.com | 2020-07-03 |
| OID | Oakdale Irrigation District | | Oakdale | | 2010-12-03 |
| OAMG | Ocean Acidification Monitoring Group | | | | 1900-01-01 |
| OCWUL | Oceanside City Water Utility Laboratory | | | | 2017-06-28 |
| OEC | Oilfield and Environmental Compliance | | Santa Maria | | 2017-05-09 |
| ORL | Oilwell Research Lab | | | | 2017-06-05 |
| CIWQS 33028 | Ojai Valley Sanitary District | | | | 1900-01-01 |
| CIWQS 32551 | Olivehurst PUD | | | | 1900-01-01 |
| OCWD | Orange City Water Department | | | | 2017-06-05 |
| OCA | Orange Coast Analytical, Inc. | | | | 2019-06-10 |
| OC | Orange County | Charlie McGee | Fountain Valley | | 2012-05-07 |
| OCEHD | Orange County Environmental Health Division | Michael Fennessy | Santa Ana | | 2012-05-07 |
| OCPHL | Orange County Public Health Lab | | | | 2012-05-07 |
| OCPW | Orange County Public Works | | | | 2013-10-29 |
| OCSD | Orange County Sanitation District | | | | 2012-05-07 |
| OCWR | Orange County Waste and Recycling | | | | 2021-01-14 |
| OCWDML | Orange County Water District Main Laboratory | | | | 2017-06-05 |
| ODEQ | Oregon Department of Environmental Quality | Steve Kirk | Portland | KIM.Won@deq.state.or.us | 2012-04-20 |
| ODEQ-KFALLS | Oregon Department of Environmental Quality, Klamath Falls | Mike Hiatt | Klamath Falls | hiatt.mike@deq.state.or.us | 2016-09-12 |
| OSU-Zoo | Oregon State University, Department of Zoology | Dave Lytle | Corvallis | | 2015-04-16 |
| OXN_PW | Oxnard City, Department of Public Works | | | | 2023-10-30 |
| PACE | Pace Analytical Service, Inc. | Unknown | Minneapolis | | 2012-05-07 |
| PACE_Camarillo | Pace Analytical Services, Inc., Camarillo | | | | 2017-06-05 |
| PAI | Pacific Analytical Inc. | | | | 2017-06-05 |
| PCAS | Pacific Coast Analytical Services | | | | 2010-10-15 |
| PER | Pacific Ecorisk | Stephen Clark | Martinez | | 2007-09-01 |
| PEL | Pacific Environmental Laboratory | | | | 2017-06-05 |
| CIWQS 33523 | Pacific Gas & Electric Company Eureka | | | | 1900-01-01 |
| PGE-San Ramon | Pacific Gas and Electric San Ramon | Catalina Reyes | San Ramon | | 2017-12-01 |
| PACRL | Pacific Ridgeline | Bryn Home | Ventura | bryn@pacrl.com | 2021-06-25 |
| CIWQS 33649 | Pacifica City | | | | 1900-01-01 |
| PacifiCorp | PacifiCorp | Linda Prendergast | Portland | linda.prendergast@pacificorp.com | 2017-03-16 |
| CIWQS 33676 | Pactiv Corp | | | | 1900-01-01 |
| CIWQS 33680 | Padre Dam Municipal Water District | | | | 1900-01-01 |
| CIWQS 33738 | Palo Alto City | | | | 1900-01-01 |
| PARWQCL | Palo Alto Regional Water Quality Control Laboratory | | | | 2017-06-05 |
| PVPWMG | Palos Verdes Peninsula Watershed Management Group | Andy Winje | Rancho Palos Verdes | andyw@rpvca.gov | 2016-06-03 |
| PDD | Panoche Drainage District | Mike Gardner | | mgpanoche@panochedd.org | 2007-09-01 |
| CIWQS 33785 | Paradise ID | | | | 1900-01-01 |
| USLT_CSL_RCD | Partnernship between Upper Salinas-Las Tablas and Coastal San Luis Resource Conservation Districts | | | | 2018-05-10 |
| PCWQL | Pasadena City Water Quality Laboratory | | | | 2017-06-05 |
| CIWQS 33896 | Paso Robles City | | | | 1900-01-01 |
| Pat-Chem | Pat-Chem Laboratories | Theresa Treviso | Moorpark | | 2012-06-08 |
| PU | Pepperdine University | | | | 2018-09-22 |
| COP | Petaluma City Waste Water Treatment Facility | | | | 2016-08-18 |
| CIWQS 12244 | Peter M. Ormand | | | | 1900-01-01 |
| CIWQS 9217 | Phillips 66 (formerly ConocoPhillips) - SF Refinery | | | | 1900-01-01 |
| Phycotech | Phycotech, Inc. | Ann St. Amand | St. Joseph | | 2019-03-14 |
| PHYSIS | PHYSIS Environmental Laboratories, Inc. | Misty Mercier | Anaheim | | 2011-09-29 |
| PMWWFPL | Pittsburg Municipal Water Works Filtration Plant Laboratory | | | | 2017-06-05 |
| CIWQS 181411 | Placer Cnty Dept of Facility Services | | | | 1900-01-01 |
| PlacerCounty | Placer County | | | | 2017-06-08 |
| CIWQS 34521 | Placerville City | | | | 1900-01-01 |
| CIWQS 483625 | Plains West Coast Terminals, LLC | | | | 1900-01-01 |
| CIWQS 34528 | PLANADA CSD | | | | 1900-01-01 |
| PluCorp | Plumas Corporation | | | | 2024-09-04 |
| PNSSNS | PNSSNS Subwatershed Group | Linda Watanabe | Lincoln | cleanwaters@netscape.com | 2012-06-07 |
| POLB | Port of Long Beach | Dylan Porter | | dylan.porter.polb.com | 2018-03-01 |
| POSD | Port of San Diego | | | | 2012-05-16 |
| PoS | Port of Stockton | | Stockton | | 2025-02-18 |
| CIWQS 34722 | Portola City | | | | 1900-01-01 |
| PowayCity | Poway City | | | | 2014-07-02 |
| PPCG | Provost & Pritchard Consulting Group | | Visalia | | 2017-08-16 |
| PTRL | PTRL West, Richmond | | | | 2017-06-05 |
| PTS | PTS Laboratories | | | | 2011-08-25 |
| PCWG | Putah Creek Watershed Group | | | | 2015-06-11 |
| QALSD | Quality Assurance Laboratory of San Diego | | | | 2017-06-05 |
| QWL | Quality Water Laboratory | | | | 2017-06-05 |
| QUANTERRA | Quanterra Lab | | | | 2017-06-05 |
| QVIR | Quartz Valley Indian Reservation | Sarah Scheafer | Fort Jones | epadirector@qvir.com; epadirector@qvir.com | 2012-04-20 |
| CIWQS 36414 | Quincy Community Services District | | | | 1900-01-01 |
| RFE_Rose | R&F Engineering, Roseville | | | | 2023-03-15 |
| RLC | Radian Lab Corporation | | | | 2017-06-05 |
| RDC | Radiation Detection Company | | | | 2017-06-05 |
| CIWQS 4573 | Ralph Beatty | | | | 1900-01-01 |
| Ramboll | Ramboll Environ | Bridget Gregg | Port Gamble | bgregg@ramboll.com | 2016-03-30 |
| REBWCL | Ray E. Beam Water Consultant Lab | | | | 2017-06-05 |
| CIWQS 36963 | Red Bluff City | | | | 1900-01-01 |
| RedHills | Red Hills Environmental, LLC | | | | 2016-11-03 |
| CIWQS 37005 | Redding City | | | | 1900-01-01 |
| RCWD | Redlands City Wastewater Division | | | | 2017-06-05 |
| CIWQS 47658 | Regents of the University of California - UC Davis | | | | 1900-01-01 |
| RESIGHINI | Resighini Racheria | Rob Cozens | Klamath | ResighiniEPA@hughes.net | 2012-04-20 |
| RCDMC | Resource Conservation District of Monterey County | | Salinas | | 2020-03-18 |
| RTD | Restore the Delta | | | | 2025-01-07 |
| Rhithron | Rhithron Associates, Inc. | | Missoula | contact@rhithron.com | 2015-12-11 |
| RPAGCO | Rhone-Poulenc Ag Company | | | | 2017-06-05 |
| CIWQS 37426 | Rio Alto WD | | | | 1900-01-01 |
| CIWQS 37430 | Rio Dell City | | | | 1900-01-01 |
| CIWQS 37437 | Rio Vista City | | | | 1900-01-01 |
| CIWQS 37474 | River Highlands CSD | | | | 1900-01-01 |
| CIWQS 502400 | Riverside City | | | | 1900-01-01 |
| RiversideCounty | Riverside County | | | | 2017-06-08 |
| RCFC | Riverside County Flood Control | Steven Clark | Riverside | seclark@rcflood.org | 2012-08-15 |
| RCSA51 | Riverside County Service Area 51 | | | | 2017-06-05 |
| RWQCP | Riverside Water Quality Control Plant | | | | 2017-04-21 |
| RCRCD | Riverside-Corona Resource Conservation District | Kerwin Russell | Riverside | | 2019-06-13 |
| RJLG | RJ Lee Group, Inc. | | | | 2017-06-05 |
| RBI | Robertson-Bryan, Inc. | | | | 2017-10-12 |
| CIWQS 37731 | Rockwell Automation | | | | 1900-01-01 |
| RIRD | Rockwell International, Rocketdyne Division | | | | 2017-06-05 |
| CIWQS 11142 | Roseville City | | | | 1900-01-01 |
| RCWWCL | Roseville City WasteWater Control Laboratory | | | | 2017-06-28 |
| RVIT | Round Valley Indian Tribes | | Covelo | | 2025-12-22 |
| RWQCB1 | RWQCB1-North Coast Region | Rich Fadness | Santa Rosa | RFadness@waterboards.ca.gov | 2007-09-01 |
| RWQCB2 | RWQCB2-San Francisco Bay Region | Karen Taberski | Oakland | KTaberski@waterboards.ca.gov | 2011-03-28 |
| RWQCB3 | RWQCB3-Central Coast Region | Karen Worcester | San Luis Obispo | Kworcester@waterboards.ca.gov | 2007-09-01 |
| RWQCB4 | RWQCB4-Los Angeles Region | Michael Lyons | Los Angeles | Mlyons@waterboards.ca.gov | 2007-09-01 |
| LACRWQCB-TMDL | RWQCB4-Los Angeles Region-TMDL | Stephen Kiyoi | Los Angeles | | 2012-05-15 |
| RWQCB5 | RWQCB5-Central Valley Region | Alisha Wenzel | Rancho Cordova | awenzel@waterboards.ca.gov | 2016-01-22 |
| RWQCB5F | RWQCB5-Central Valley Region (Fresno) | Bethany Soto | Fresno | bsoto@waterboards.ca.gov | 2012-01-17 |
| RWQCB5L | RWQCB5-Central Valley Region (Lower Sacramento) | Alisha Wenzel | Rancho Cordova | awenzel@waterboards.ca.gov | 2012-01-17 |
| RWQCB5R | RWQCB5-Central Valley Region (Redding) | Alisha Wenzel | Rancho Cordova | awenzel@waterboards.ca.gov | 2020-02-10 |
| RWQCB5S | RWQCB5-Central Valley Region (Sacramento) | Alisha Wenzel | Rancho Cordova | awenzel@waterboards.ca.gov | 2012-01-17 |
| RWQCB5U | RWQCB5-Central Valley Region (Upper Sacramento) | Alisha Wenzel | Rancho Cordova | awenzel@waterboards.ca.gov | 2012-01-17 |
| RWQCB6 | RWQCB6-Lahontan Region | Thomas Suk | South Lake Tahoe | TSuk@waterboards.ca.gov | 2007-09-01 |
| RWQCB6V | RWQCB6-Lahontan Region (Victorville) | | South Lake Tahoe | | 2025-07-14 |
| RWQCB7 | RWQCB7-Colorado River Basin Region | Jeff Geraci | Palm Desert | jgeraci@waterboards.ca.gov | 2012-01-17 |
| RWQCB8 | RWQCB8-Santa Ana Region | Pavlova Vitale | Riverside | hboyd@waterboards.ca.gov | 2012-01-17 |
| RWQCB9 | RWQCB9-San Diego Region | Lilian Busse | San Diego | lbusse@waterboards.ca.gov | 2012-01-17 |
| CIWQS 39410 | Sacramento City | | | | 1900-01-01 |
| SCARWTP | Sacramento City American River Water Treatment Plant | | | | 2017-06-28 |
| CIWQS 39382 | Sacramento Cnty Solid Waste Management | | | | 1900-01-01 |
| SacramentoCounty | Sacramento County | | | | 2017-06-08 |
| SCEQCL | Sacramento County Environmental Quality Control Laboratory | | | | 2017-06-28 |
| SMUD | Sacramento Municipal Utility District | Tyler Belarde | Pollock Pines | tyler.belarde@smud.org | 2018-05-09 |
| SRCSD | Sacramento Regional County Sanitation District | | | | 2017-02-28 |
| CIWQS 39399 | Sacramento Regional CSD | | | | 1900-01-01 |
| SRWTP | Sacramento Regional Wastewater Treatment Plant | | Elk Grove | | 2016-06-06 |
| SRWP | Sacramento River Watershed Program | Holly Jorgensen | Chico | holly@sacriver.org | 2016-03-14 |
| SVWQC | Sacramento Valley Water Quality Coalition | Bruce Houdelsheldt, Donn Zea (NCWA) | Sacramento | bruceh@norcalwater.org | 2009-09-24 |
| SSJDC | Sacramento-San Joaquin Delta Conservancy | Shakoora Azimi-Gaylon | West Sacramento | shakoora.azimi-gaylon@deltaconservancy.ca.gov | 2015-06-01 |
| SALCO | Salco Laboratory Services | | | | 2017-06-05 |
| SRRC | Salmon River Restoration Council | Lyra Cressey | Sawyers Bar | lyra@srrc.org | 2012-04-20 |
| SRF | Salmonid Restoration Federation | Katrina Nystrom | Eureka | katrina@calsalmon.org | 2022-02-04 |
| CIWQS 39539 | San Andreas SD | | | | 1900-01-01 |
| SanBenitoCounty | San Benito County | | | | 2017-06-08 |
| SBC | San Bernardino County | Darryl Tafoya | San Bernardino | dtafoya@dpw.sbcounty.gov | 2012-05-07 |
| SBCFC | San Bernardino County Flood Control | | | | 2017-06-28 |
| SBCP | San Bernardino County Parks | | | | 2023-07-12 |
| SBCSL | San Buenaventura City Sanitation Laboratory, Ventura | | | | 2017-06-05 |
| SCCPW | San Clemente City Public Works | | | | 2018-06-29 |
| SCWRP | San Clemente City Water Reclamation Plant | | | | 2017-06-05 |
| SDAA | San Diego Airport Authority | | | | 2015-07-06 |
| SDCity | San Diego City | | | | 2023-12-08 |
| SDCPUD | San Diego City Public Utilities Department, La Mesa | | | | 2017-06-05 |
| SDCK | San Diego Coastkeeper | | San Diego | | 2023-10-20 |
| SDC | San Diego County | Steven DiDonna | San Diego | steven.didonna@sdcounty.ca.gov | 2012-05-07 |
| SDCDEH | San Diego County Department of Environmental Health | Ewan Moffat | San Diego | | 2012-05-07 |
| SDCPHL | San Diego County Public Health Laboratory | Brett Austin | San Diego | Brett.Austin@sdcounty.ca.gov | 2018-12-10 |
| SDRPF | San Diego River Park Foundation | | | | 2016-03-18 |
| SDSU-HL | San Diego State University - Hoh Laboratory | | | | 2026-03-12 |
| CIWQS 39664 | San Elijo Joint Powers | | | | 1900-01-01 |
| SEJPA | San Elijo Joint Powers Authority | Unknown | Cardiff by the Sea | | 2012-05-07 |
| SELC | San Elijo Lagoon Conservancy | Bradley Nussbaum | Encinitas | bradley@sanelijo.org | 2014-03-06 |
| SanFranciscoCity | San Francisco City | | | | 2017-06-08 |
| SanFranciscoCounty | San Francisco County | | | | 2017-06-08 |
| SFDPH | San Francisco Department of Public Health | Ned Shitara | San Francisco | | 2012-05-07 |
| SFEI | San Francisco Estuary Institute | Cristina Grosso | Oakland | cristina@sfei.org | 2007-12-21 |
| SFIA | San Francisco International Airport | | | | 2017-06-05 |
| SFPUC-RSWPCP | San Francisco Public Utilities Commision, Richmond-Sunset Water Pollution Control Plant | | | | 2017-06-28 |
| SFPUC-STP | San Francisco Public Utilities Commision, Southeast Treatment Plant | | | | 2017-06-28 |
| SFPUC-WDDNR | San Francisco Public Utilities Commission Water Department Division of Natural Resources | | | | 2016-02-04 |
| SFSU-RTC | San Francisco State University - Romberg Tiburon Center | Al Marchi | Tiburon | amarchi@rtc.sfsu.edu | 2011-06-09 |
| SGERC | San Gregorio Environmental Resource Center | | San Gregorio | hello@sgerc.org | 2026-06-02 |
| SJDWQC | San Joaquin and Delta Water Quality Coaliton, ILRP | | | | 2017-06-08 |
| SanJoaquinCounty | San Joaquin County | | | | 2017-06-08 |
| SJCRD38 | San Joaquin County Reclamation District No. 38 Staten Island | | Thornton | ReclamationDistrict38@gmail.com | 2025-08-26 |
| SJVDA | San Joaquin Valley Drainage Authority | | | | 2016-06-14 |
| SJSURF | San Jose State University Research Foundation | | San Jose | | 2015-01-28 |
| SJSCRWF | San Jose-Santa Clara Regional Wastewater Facility | | San Jose | | 2016-02-17 |
| SLDMWA | San Luis and Delta Mendota Water Authority | | | | 2019-06-17 |
| CIWQS 39771 | San Luis Obispo City | | | | 1900-01-01 |
| SLOCWTP | San Luis Obispo City Water Treatment Plant | | | | 2017-06-28 |
| SanLuisObispoCounty | San Luis Obispo County | | | | 2017-06-08 |
| SLOCPHDEH | San Luis Obispo County Public Health Department Environmental Health | Liberty Amanson | San Luis Obispo | | 2012-05-07 |
| SLOCPHDL | San Luis Obispo County Public Health Department Lab | Dr. Jim Beebe | San Luis Obispo | | 2015-04-07 |
| SLODPW | San Luis Obispo County Public Works Department | Shane Bennett | San Luis Obispo | sdbennett@co.slo.ca.us | 2014-09-12 |
| SLO_City | San Luis Obispo, City of | | | | 2024-08-28 |
| SLR | San Luis Rey Wastewater Department | | | | 2016-06-10 |
| SLWD | San Luis Water District | | Los Banos | youtellus@sldmwa.org | 2016-12-11 |
| SMBOMI | San Manuel Band Of Mission Indians | | | | 2017-06-05 |
| SanMarcosCity | San Marcos City | | | | 2014-07-02 |
| CIWQS 39800 | San Mateo City | | | waterboard@cityofsanmateo.org | 2018-01-30 |
| SanMateoCounty | San Mateo County | | | | 2017-06-08 |
| SMCL | San Mateo County - Public Health Lab | Craig Blackmore | San Mateo | cblackmore@smcgov.org | 2012-08-30 |
| SMCRCD | San Mateo County Resource Conservation District | Kellyx Nelson | Half Moon Bay | Kellyx@sanmateorcd.org | 2014-04-10 |
| SMCWPPP | San Mateo Countyside Water Pollution Prevention Program | Lucy Buchan | | buchan@eoainc.com | 2012-08-30 |
| SO | San Onofre Generating Station | | | | 2012-05-07 |
| SPAWNERS | San Pablo Watershed Neighbors Education and Restoration Society | Helen Fitanides | Richmond | helen@thewatershedproject.org | 2016-11-15 |
| SFI | Sanctuary Forest, Inc. | | | | 2021-11-12 |
| SOCI | Sanitation And Operation Consultants, Inc. | | | | 2017-06-05 |
| SAC | Santa Ana City | | | | 2022-07-29 |
| SARDA | Santa Ana River Dischargers Association | Bobby Gustafson | Riverside | Bobby.Gustafson@riversideca.gov | 2019-03-14 |
| CIWQS 39886 | Santa Ana Watershed Project Authority | | | | 1900-01-01 |
| SAWPA | Santa Ana Watershed Protection Authority | Peter Vitt | Riverside | pvitt@sawpa.org | 2012-09-11 |
| SBCK | Santa Barbara Channelkeeper | Jenna Driscoll | Santa Barbara | jennad@sbck.org | 2016-12-15 |
| SBarbC | Santa Barbara City | Jill Murray | Santa Barbara | jmurray@santabarbaraca.gov | 2017-08-01 |
| SBCDPWWL | Santa Barbara City Dept of Public Works Wastewater Laboratory | | | | 2017-06-05 |
| SantaBarbaraCounty | Santa Barbara County | | | | 2017-06-08 |
| SBCPCW | Santa Barbara County - Project Clean Water | Cathleen Garnand | Santa Barbara | cgarnan@cosbpw.net | 2018-11-15 |
| SBEHS | Santa Barbara County Environmental Health Services | Willie Brummett | Santa Barbara | | 2012-05-07 |
| SantaClaraCounty | Santa Clara County | | | | 2017-06-08 |
| SCCDH | Santa Clara County Dept of Health, Occupational Health and Safety | | | | 2017-06-05 |
| SCCWDRWTP | Santa Clara County Water District Rinconada Water Treatment Plant | | | | 2017-06-05 |
| SCVURPPP | Santa Clara Valley Urban Runoff Pollution Prevention Program | Chris Sommers | | csommers@eoainc.com | 2012-08-30 |
| SCVWD | Santa Clara Valley Water District | | | | 2017-06-05 |
| CIWQS 39958 | Santa Cruz City | | | | 1900-01-01 |
| SCCWPCEL | Santa Cruz City Water Pollution Control Environmental Laboratory | | | | 2017-06-28 |
| SantaCruzCounty | Santa Cruz County | | | | 2017-06-08 |
| SCCEHS | Santa Cruz County Environmental Health Service | Steve Peters | Santa Cruz | | 2012-05-07 |
| SCMUL | Santa Cruz Municipal Utilities Lab | | | | 2017-06-05 |
| SMBBC_CIMP | Santa Monica Bay Beach Cities CIMP Group | | | | 2016-11-28 |
| SMCDPWWD | Santa Monica City Dept of Public Works Water Division | | | | 2017-06-05 |
| CIWQS 148702 | Santa Rosa City Dept of Public Works | | | | 1900-01-01 |
| SYCEA | Santa Ynez Chumash Environmental Office | | | | 2017-06-05 |
| SCWTPL | Santee City Wastewater Treatment Plant Laboratory | | | | 2017-06-05 |
| SAIC | Science Applications International Corporation | | | | 2012-08-30 |
| SCIENV | Scientific Environmental Laboratories | | | | 2017-06-05 |
| SCOTT | Scott Laboratories, Petaluma | | | | 2017-06-05 |
| S3LAB | S-Cubed Lab | | | | 2017-06-05 |
| SEA | Sea Education Association | | | | 2017-05-01 |
| SeaWorld | SeaWorld Parks and Entertainment | | | | 2019-12-18 |
| CIWQS 40389 | Seeley Cnty WD | | | | 1900-01-01 |
| SEPRO | SePRO Corporation | | Carmel | | 2012-08-30 |
| SAL-MH | Sequoia Analytical - Morgan Hill | | Morgan Hill | | 2016-12-07 |
| SAL-WC | Sequoia Analytical - Walnut Creek | A Kemp | Walnut Creek | | 2016-06-06 |
| SAL | Sequoia Analytical Laboratories, Inc. | Patty Penner | Petaluma | ppenner@sequoialabs.com | 2007-09-01 |
| SEQUOIA | Sequoia Analytical Laboratory, Redwood City | | | | 2017-06-05 |
| CIWQS 40516 | SEWER AUTHORITY MID-COASTSIDE | | | | 1900-01-01 |
| CIWQS 40517 | Sewerage Commission Oroville Region | | | | 1900-01-01 |
| SGS AXYS | SGS AXYS Analytical Services Ltd. | Andrew Porat | Sidney | aporat@axys.com | 2017-06-07 |
| SGS-Clovis | SGS North America Clovis | | Clovis | | 2026-02-23 |
| ShastaCounty | Shasta County | | | | 2017-06-08 |
| CIWQS 40607 | Shasta CSA #17 | | | | 1900-01-01 |
| CIWQS 40620 | Shasta Lake City | | | | 1900-01-01 |
| SVRCD | Shasta Valley Resource Conservation District | Karen Mallory | Yreka | mnkmallory@sbcglobal.net | 2012-04-20 |
| SHN-Willits | SHN Engineers & Geologists, Inc. - Willits | | Willits | | 2017-09-05 |
| SierraLabs | Sierra Analytical Labs, Inc. | Rick Forsythe | Laguna Hills | Sierralabs@sierralabs.net | 2016-01-27 |
| SIERRA | Sierra Cascade Laboratory | | | | 2017-06-05 |
| SEM | Sierra Environmental Monitoring, Inc. | | | sem@sem-analytical.com | 2007-09-01 |
| SFL | Sierra Foothill Laboratory, Inc. | Sandy Nurse | Jackson | sfl@volcano.net | 2007-09-01 |
| SNARL | Sierra Nevada Aquatic Research Laboratory | David Herbst | Mammoth Lakes | herbst@lifesci.ucsb.edu | 2007-09-01 |
| SPI-Redding | Sierra Pacific Industries - Redding | Cajun James | Redding | | 2017-09-20 |
| CIWQS 40887 | Sierra Pacific Industries Arcata | | | | 1900-01-01 |
| CIWQS 449187 | Sierra Pacific Industries Burney | | | | 1900-01-01 |
| CIWQS 40884 | Sierra Pacific Industries Quincy | | | | 1900-01-01 |
| CIWQS 40878 | Sierra Pacific Industries Redding | | | | 1900-01-01 |
| SSI_FDC | Sierra Streams Institute | | | | 2017-03-06 |
| STL | Sierra Testing Laboratories, Inc. | | El Dorado Hills | | 2012-08-30 |
| SLKR | Silliker, Inc. | | Modesto | | 2009-02-19 |
| SilverState | Silver State Analytical Laboratories, Inc. | | | | 2017-07-03 |
| CIWQS 43973 | Simi Valley City | | | | 1900-01-01 |
| SiskiyouCounty | Siskiyou County | | | | 2017-06-08 |
| Siskiyou-RCD | Siskiyou Resource Conservation District | Erich Yokel | Etna | eyokel@sisqtel.net | 2012-04-20 |
| SRA | Smith River Alliance | Monica Scholey | Crescent City | monica@smithriveralliance.org | 2022-03-04 |
| SMITHEMERY | Smith-Emery Company Dept of Chemistry | | | | 2017-06-05 |
| SPLI | Soil & Plant Laboratory Inc. | | | | 2017-06-05 |
| SCL | Soil Control Laboratory | Mike Galloway | Watsonville | mike@controllabs.com | 2009-02-06 |
| SolanaBeachCity | Solana Beach City | | | | 2014-07-02 |
| SolanoCounty | Solano County | | | | 2017-06-08 |
| Solano CWA | Solano County Water Agency | Alexander Rabidoux | Vacaville | arabidoux@scwa2.com | 2017-02-24 |
| SOLANOID | Solano Irrigation District | | | | 2017-06-05 |
| Solano RCD | Solano Resource Conservation District | Amy King | Dixon | amy.king@solanorcd.org | 2013-11-15 |
| SSA | Solano Stormwater Alliance | | | | 2023-10-27 |
| CIWQS 41499 | Sonoma Cnty Water Agency (SCWA) R1 | | | | 1900-01-01 |
| SonomaCounty | Sonoma County | | | | 2017-06-08 |
| SCAPOSD | Sonoma County Agricultural Preservation and Open Space District | Bill Keene | | openspace@sonoma-county.org | 2016-11-01 |
| SCPRMD | Sonoma County Permit and Resource Management Department | | Santa Rosa | | 2017-02-06 |
| SCPHRL | Sonoma County Public Health Regional Laboratory | Michael Ferris | Santa Rosa | Michael.Ferris@sonoma-county.org | 2015-10-26 |
| SCWA | Sonoma County Water Agency | Nazareth Tesfai | Santa Rosa | nazareth.Tesfai@scwa.ca.gov | 2016-10-18 |
| SEC | Sonoma Ecology Center | | Eldridge | | 2017-02-15 |
| SMC | Source Molecular Corporation | Mauricio Larenas | Miami | info@sourcemolecular.com | 2015-01-28 |
| SCWD | South Coast Water District | | | | 2024-12-03 |
| SDAL | South Dakota Agricultural Laboratories | | Brookings | regina.wixon@sdaglabs.com | 2019-08-09 |
| SEM_City | South El Monte City | | South El Monte | | 2026-01-23 |
| CIWQS 41573 | South Feather Water & Power Agency | | | | 1900-01-01 |
| SSJID | South San Joaquin Irrigation District | Stevan Stroud | Manteca | | 2009-09-24 |
| SoSCCo_RegPartners | South Santa Clara County Regional Partners | | | | 2021-10-18 |
| STPUDL | South Tahoe Public Utility District Laboratory | | | | 2017-06-05 |
| SYRCL | South Yuba River Citizens League | Jesse Armfield | Nevada City | jesse@yubariver.org | 2018-12-18 |
| SRRA | Southeast Regional Reclamation Authority | Ann Harley | Dana Point | | 2012-05-07 |
| SCAMIT | Southern California Association of Marine Invertebrate Taxonomists | Larry Lovell | Carson | Llovell@lacsd.org | 2010-03-18 |
| SCCWRP | Southern California Coastal Water Research Project | Eric Stein | Costa Mesa | erics@sccwrp.org | 2007-09-01 |
| SCE | Southern California Edison | | | | 2024-07-19 |
| CIWQS 44116 | Southern California Edison- Rosemead | | | | 1900-01-01 |
| SIU | Southern Illinois University | Michael Lydy | Carbondale | mlydy@siu.edu | 2007-09-01 |
| SOCWA | Southern Orange County Water Authority | | | | 2012-05-07 |
| SSJWQC | Southern San Joaquin Water Quality Coalition | David Orth, Bill Thomas | Fresno | dorth@krcd.org | 2009-09-24 |
| SAFIT | Southwest Association of Freshwater Invertebrate Taxonomists | Joseph Slusark | Chico | slusark@csuchico.edu | 2010-02-10 |
| SDWCL | Sparkletts Drinking Water Corp Lab, McKesson Water Division | | | | 2017-06-05 |
| SPECTRUM | Spectrum Labs, Inc. | | | | 2017-06-05 |
| SRWQL | Sprague River Water Quality Lab | | Chiloquin | | 2014-10-06 |
| SRES | Spring Rivers Ecological Sciences | | | | 2021-10-27 |
| SVLA | Spring Valley Lake Association | | | | 2023-10-26 |
| CIWQS 41889 | SPX Corp | | | | 1900-01-01 |
| CIWQS 41942 | ST. HELENA CITY | | | | 1900-01-01 |
| CIWQS 41969 | Stallion Springs CMSD | | | | 1900-01-01 |
| Stanford ELC | Stanford Environmental Law Clinic | | | | 2022-11-02 |
| Stanford | Stanford Univ | | | | 2014-07-07 |
| StanislausCounty | Stanislaus County | | | | 2017-06-08 |
| Stantec_SD | Stantec Consulting Services Inc., San Diego Office | | | | 2022-07-29 |
| Stantec_SJ | Stantec Consulting Services Inc., San Jose Office | Laura Casali | San Jose | laura.casali@stantec.com | 2025-10-23 |
| Stantec_ZC | Stantec Consulting Services Inc., Zephyr Cove Office | | Zephyr Cove | | 2024-03-08 |
| SRS | Starr Ranch Sanctuary | Scott Gibson | | | 2013-09-24 |
| SFCWA | State and Federal Contractors Water Agency | Stephanie Fong | Sacramento | sfong@sfcwa.org | 2018-03-04 |
| CAWCB | State of California Wildlife Conservation Board | | | | 2017-07-24 |
| SWRCB | State Water Resources Control Board | Lori Webber | Sacramento | lwebber@waterboards.ca.gov | 2012-01-17 |
| SWRCB-SWAMP | State Water Resources Control Board - Surface Water Ambient Monitoring Program | | | | 2017-06-08 |
| SWRCB-SWAMP-BOG | State Water Resources Control Board - Surface Water Ambient Monitoring Program - Bioaccumulation Oversight Program | | | | 2016-02-03 |
| SWRCB-SWAMP-CHAB | State Water Resources Control Board - Surface Water Ambient Monitoring Program - Cyanobacteria Harmful Algal Bloom Monitoring Program | | | | 2016-02-03 |
| SWRCB-SWAMP-EPA-NS | State Water Resources Control Board - Surface Water Ambient Monitoring Program - EPA National Surveys Participation | | | | 2016-02-03 |
| SWRCB-SWAMP-PSA | State Water Resources Control Board - Surface Water Ambient Monitoring Program - Perennial Streams Assessment | | | | 2016-02-03 |
| SWRCB-SWAMP-RCMP | State Water Resources Control Board - Surface Water Ambient Monitoring Program - Reference Condition Management Program | | | | 2016-02-03 |
| SWRCB-SWAMP-SPoT | State Water Resources Control Board - Surface Water Ambient Monitoring Program - Stream Pollution Trends Monitoring Program | | | | 2016-02-03 |
| CIWQS 44632 | Stellar Biotechnologies, Inc | | | | 1900-01-01 |
| Stetson_Carlsbad | Stetson Engineers, Carlsbad Office | | Carlsbad | | 2021-07-02 |
| Stetson_SanRafael | Stetson Engineers, San Rafael Office | Joel Barnard | San Rafael | joelb@stetsonengineeers.com | 2022-04-14 |
| SRH | Steve Hanson and Associates | Steve R. Hanson | | | 2007-12-21 |
| SWS | Stillwater Sciences | Krista Orr | Davis | Krista@stillwatersci.com | 2016-02-01 |
| CIWQS 4247 | Stimpel-Wiebelhaus Associates | | | | 1900-01-01 |
| CIWQS 42240 | Stockton City | | | | 1900-01-01 |
| SCMUD | Stockton City Municipal Utilities District | | Stockton | | 2017-06-05 |
| SEWD | Stockton East Water District | | | | 2022-12-07 |
| SESJWCD | Stockton-E. San Joaquin Water Conservation District | | | | 2017-06-05 |
| SCID | Stone Corral Irrigation District | | | | 2017-06-05 |
| STONER | Stoner Lab | | | | 2017-06-05 |
| SETTEK | Summit Environmental Technologies, Inc | | Cuyahoga Falls | | 2016-08-01 |
| SUN-MTV | Sunnyvale City - Mountain View City | | | | 2024-10-01 |
| SCWPCPL | Sunnyvale City Water Pollution Control Plant Lab | | | | 2017-06-05 |
| SunStar | SunStar Laboratories | | Lake Forest | | 2013-10-01 |
| Surfrider | Surfrider Foundation | | | | 2022-11-02 |
| McCormick | Susan McCormick | Susan McCormick | Georgetown | mcwoods47@sbcglobal.net | 2012-08-30 |
| SLSII | Sustainable Land Stewardship International Institute | | | | 2017-04-25 |
| SBFCA | Sutter Butte Flood Control Agency | | | | 2023-03-15 |
| SutterCounty | Sutter County | | | | 2017-06-08 |
| CIWQS 42701 | Sweetwater Authority | | | | 1900-01-01 |
| SweetwaterFP | Sweetwater Filtration Plant | | | | 2017-06-28 |
| SWRCB-SMC | SWRCB Stormwater Monitoring Coalition | | | | 2016-03-11 |
| TKPOA | Tahoe Keys Property Owners Association | Greg Hoover | South Lake Tahoe | GHoover@tahoekeyspoa.org | 2018-12-04 |
| TKWQL | Tahoe Keys Water Quality Laboratory | | | | 2017-06-05 |
| TPP | Tahoe Paradise Park | | | | 2023-07-12 |
| TRPA | Tahoe Regional Planning Agency | Beth Vollmer | Stateline | bvollmer@trpa.org | 2013-02-13 |
| TahoeRCD | Tahoe Resource Conservation District | Andrea Buxton | South Lake Tahoe | abuxton@tahoercd.org | 2015-09-09 |
| TKSA | Tahoe Truckee Sanitation Agency | | | | 2017-06-05 |
| TDI-BI | TDI-Brooks International | | | | 2012-08-30 |
| CIWQS 45432 | Tehama Co SD #1 | | | | 1900-01-01 |
| TehamaCounty | Tehama County | | | | 2017-06-08 |
| TC | Temecula City | | Temecula | | 2018-01-30 |
| TTLI | Terra Tech Labs, Inc. | | | | 2017-06-05 |
| CIWQS 538992 | Test | | | | 1900-01-01 |
| TestAmerica | Test America Laboratories, Inc. | | | | 2015-04-24 |
| TCL | Testing and Controls Lab | | | | 2017-06-05 |
| TetraTech | Tetra Tech, Inc. | Tim Tringali | Santa Maria | tim.tringali@tetratech.com | 2013-08-07 |
| TEX-AM | Texas A&M University | Dr. Robert J. Taylor | College Station | | 2012-05-07 |
| 5Gyres | The 5 Gyres Institute | Carolyn Box | | carolynn@5gyres.org | 2018-04-26 |
| BFMB | The Bay Foundation of Morro Bay | Gary Ruggerdone | Morro Bay | | 2015-06-24 |
| CIWQS 39738 | The City of San Juan Bautista | | | | 1900-01-01 |
| MCCCL | The Monterey County Consolidated Chemistry Lab | | Montery | | 2012-10-05 |
| TNC | The Nature Conservancy | | | | 2017-03-08 |
| TNC-BIGSPRINGS | The Nature Conservancy Big Springs | Amy Hoss | Mount Shasta | ahoss@tnc.org | 2012-04-20 |
| TNC-KFALLS | The Nature Conservancy Williamson River Delta | Heather Hendrixson | Klamath Falls | hhendrixson@tnc.org | 2012-04-20 |
| CSUSD-SafeWaTER | The Safe WaTER Laboratory at California State University, San Diego | Matthew Verbyla | San Diego | mverbyla@sdsu.edu | 2024-01-26 |
| TSF | The Sierra Fund | Nick Graham | Nevada City | nick.graham@sierrafund.org | 2018-11-27 |
| TWL | The Twining Laboratories, Inc. | Ronald J. Boquist | Fresno | ronb@twining.com | 2007-09-01 |
| CIWQS 45707 | THE VENDO COMPANY | | | | 1900-01-01 |
| TWP | The Watershed Project | Helen Fitanides | Richmond | helen@thewatershedproject.org | 2017-09-12 |
| TWC | The Wildlands Conservancy | Zach Kantor-Anaya | Oak Glen | zach.k@wildlandsconservancy.org | 2022-06-02 |
| THERMOL | Thermol Analytical Lab | | | | 2017-06-05 |
| TA | Thomas Analytical | | | | 2012-05-07 |
| CIWQS 47044 | Thousand Oaks City | | | | 1900-01-01 |
| TOCWWTPL | Thousand Oaks City WasteWater Treatment Plant Laboratory | | | | 2017-06-28 |
| TPC | Timber Products Company | Stuart Farber | Yreka | stuf@sor.teamtp.com | 2012-04-20 |
| TDN | Tolowa Dee-ni Nation | Ridge McLennan | Smith River | ridge.mclennan@tolowa.com | 2018-05-22 |
| Torrent | Torrent Laboratory, Inc. | Kathie Evans | Milpitas | pm@torrentlaboratory.com | 2015-08-20 |
| TOTALFLOW | Total Flow, Inc. | | | | 2014-08-04 |
| ToxScan | ToxScan | Dave Lewis | Watsonville | dlewis@toxscan.com | 2007-09-01 |
| CIWQS 46150 | Tracy City | | | | 1900-01-01 |
| TCWTP | Tracy City Water Treatment Plant | | | | 2017-06-28 |
| TrinityCounty | Trinity County | | | | 2017-06-08 |
| TU | Trout Unlimited | | | | 2017-07-24 |
| SCTU | Trout Unlimited South Coast | | | | 2025-05-28 |
| TRWC | Truckee River Watershed Council | Beth Christman | Truckee | bchristman@truckeeriverwc.org | 2012-05-11 |
| Truesdail | Truesdail Laboratories, Inc. | | | | 2015-04-24 |
| TulareCounty | Tulare County | | | | 2017-06-08 |
| TBWQC | Tule Basin Water Quality Coalition | David DeGroot | Visalia | davidd@4-creeks.com | 2014-07-09 |
| Tule SW | Tule River Sub-Watershed | | | | 2011-03-24 |
| TuolomneCounty | Tuolomne County | | | | 2017-06-08 |
| TuolumneRCD | Tuolumne County Resource Conservation District | | Sonora | | 2010-10-19 |
| TuolumneRT | Tuolumne River Trust | | Sonora | | 2010-10-19 |
| CIWQS 46497 | Tuolumne Utilities District | | | | 1900-01-01 |
| CIWQS 46509 | Turlock City | | | | 1900-01-01 |
| TCWQCL | Turlock City Water Quality Control Laboratory | | | | 2017-06-28 |
| TID | Turlock Irrigation District | Robert M. Nees | Turlock | | 2009-09-24 |
| TLSC | Twining Labs Southern California | | | | 2017-06-05 |
| USBR-SCCAO | U.S. Bureau of Reclamation - SCCAO | Stacy Brown | Fresno | sbrown@usbr.gov | 2012-08-30 |
| USBR-CGBRO | U.S. Bureau of Reclamation California-Great Basin Regional Office | Brian Urbick | Sacramento | burbick@usbr.gov | 2022-10-18 |
| USBR-KFALLS | U.S. Bureau of Reclamation Klamath Falls | Rick Carlson | Klamath Falls | racarlson@mp.usbr.gov; jasbill@mp.usbr.gov | 2012-04-20 |
| USBR-NC | U.S. Bureau of Reclamation Northern California Area Office, NC 312 | Paul Zedonis | Shasta Lake | pzedonis@usbr.gov | 2013-09-26 |
| USBR-TRINITY | U.S. Bureau of Reclamation Trinity | Eric Peterson | Weaverville | ebpeterson@usbr.gov | 2012-04-20 |
| USFWS-Arcata | U.S. Fish and Wildlife Service Arcata Fish and Wildlife Office | Nick Hetrick | Arcata | nick_hetrick@fws.gov | 2012-03-21 |
| USFWS-Klamath | U.S. Fish and Wildlife Service Klamath Falls Office | | | | 2012-10-23 |
| USFWS | U.S. Fish and Wildlife Services - Sacramento | | | | 2013-01-17 |
| USFS | U.S. Forest Service | Lisa Petrusa | | | 2012-05-07 |
| USFS-AREMP | U.S. Forest Service AREMP | Steve Lanigan | Portland | slanigan@fs.fed.us | 2012-04-20 |
| USFS-FREMONT-WINEMA | U.S. Forest Service Fremont Winema | Dick Ford | Klamath Falls | richard_ford@fs.fed.us | 2012-04-20 |
| USFS-KLAMATH | U.S. Forest Service Klamath Butte | Greg Laurie | Yreka | glaurie@fs.fed.us | 2012-04-20 |
| USFS-LAKE TAHOE | U.S. Forest Service Lake Tahoe | | South Lake Tahoe | | 2025-11-14 |
| USFS-LASSEN | U.S. Forest Service Lassen | | | | 2023-07-25 |
| USFS-MODOC | U.S. Forest Service Modoc | Marty Yamagiwa | Alturas | myamagiwa@fs.fed.us | 2012-04-20 |
| USFS-San Bernardino | U.S. Forest Service San Bernardino | Bill Wells | San Bernardino | williamewells@fs.fed.us | 2012-05-07 |
| USFS-SHASTA-TRINITY | U.S. Forest Service Shasta Trinity | Christine Mai | Redding | cmai@fs.fed.us | 2012-04-20 |
| USFS-SIX-RIVERS | U.S. Forest Service Six Rivers | LeRoy Cyr | Orleans | lcyr@fs.fed.us | 2012-04-20 |
| USFS-VALLEJO | U.S. Forest Service Vallejo | Joseph Furnish | Vallejo | jfurnish01@fs.fed.us | 2013-03-19 |
| USGS-PCMSC | U.S. Geological Survey - Pacific Coastal and Marine Science Center | | Santa Cruz | | 2015-09-28 |
| USGS-KFALLS | U.S. Geological Survey Klamath Falls | Sara Eldridge | Klamath Falls | seldridge@usgs.gov | 2012-04-20 |
| USGS-CAWSC | U.S. Geological Survey-California Water Science Center | Jim Orlando | Sacramento | jorlando@usgs.gov | 2018-03-04 |
| USGS-CB | U.S. Geological Survey-Carnelian Bay Field Office | Gerald Rockwell | Carnelian Bay | glrock@usgs.gov | 2007-09-01 |
| USGS-FRESC | U.S. Geological Survey-Forest and Rangeland Ecosystem Science Center | Collin Eagles-Smith | Corvallis | ceagles-smith@usgs.gov | 2012-11-06 |
| USGS-MRL | U.S. Geological Survey-Mercury Research Laboratory | John F. DeWild | Middleton | jfdewild@usgs.gov | 2014-12-12 |
| USGS-NWQL | U.S. Geological Survey-National Water Quality Laboratory | GS-W-COden NWQL LabHelp | Denver | labhelp@usgs.gov | 2013-05-09 |
| USGS-Scto | U.S. Geological Survey-Water Resources-Sacramento | Lawrence A. LeBlanc | Sacramento | lleblanc@usgs.gov | 2007-09-01 |
| USGS-WERC | U.S. Geological Survey-Western Ecological Research Center | Collin Eagles-Smith | | | 2013-05-13 |
| NPS-Whiskeytown | U.S. National Park Service-Whiskeytown National Recreation Area | | | | 2022-05-26 |
| USNV | U.S. Navy | Jeff Grovig | San Diego | | 2012-05-16 |
| CIWQS 470633 | UC Davis | | | | 1900-01-01 |
| UCD-AL | UC Davis Analytical Laboratory | Traci Francis | Davis | anlab@ucdavis.edu | 2020-03-13 |
| UCD-SIF | UC Davis Stable Isotope Facility | David Harris | Davis | dharris@ucdavis.edu | 2007-12-21 |
| UCD-AHPL | UC Davis-Aquatic Health Program Laboratory | Marie Stillway | Davis | ladeanovic@ucdavis.edu | 2015-08-17 |
| UCD-FCCL | UC Davis-Fish Conservation and Culture Laboratory | | | | 2017-10-03 |
| UCD-SVM | UC Davis-School of Veterinary Medicine | | Davis | | 2016-03-17 |
| UCLA | UC Los Angeles | | | | 2014-07-08 |
| UC Merced EAL | UC Merced Environmental Analytical Laboratory | | | | 2021-06-04 |
| UCR-ESRL | UC Riverside - Environmental Sciences Research Laboratory | | Riverside | | 2014-09-20 |
| CIWQS 285299 | UC San Diego | | | | 1900-01-01 |
| UCSD-SIO | UCSD Scripps Institution of Oceanography Oceanic | Dr. Andrew Dickson | | | 2013-09-26 |
| CIWQS 47705 | Ukiah City | | | | 1900-01-01 |
| CIWQS 47737 | Uni-Kool Company | | | | 1900-01-01 |
| UnionCity | Union City | Thomas Ruark | Union City | ThomasR@ci.union-city.ca.us | 2016-09-22 |
| CIWQS 47784 | Union Pacific RR Company | | | | 1900-01-01 |
| USD | Union Sanitary District | Jim Chen | Union City | Jim_Chen@unionsanitary.com | 2007-12-21 |
| CIWQS 485093 | United Auburn Indian Community | | | | 1900-01-01 |
| UCSB-MSI | University of California at Santa Barbara Marine Science Institute | Uta Passow | Santa Barbara | uta.passow@lifesci.ucsb.edu | 2013-09-26 |
| UCB-WL | University of California Berkeley-Weston Lab | Don Weston | Richmond | dweston@berkeley.edu | 2007-09-01 |
| UCCE_Monterey | University of California Cooperative Extension Monterey County | | | | 2017-01-31 |
| UCD_HGL | University of California Davis - Mercury Lab | Darell G. Slotton | Davis | dgslotton@ucdavis.edu | 2012-08-30 |
| UCD-ATW | University of California Davis Atwill Lab | Xunde Li | Davis | xdli@ucdavis.edu | 2010-05-04 |
| UCD-GGE | University of California Davis Graduate Group in Ecology | | Davis | | 2012-07-06 |
| UCD-PES | University of California Davis Plant and Environmental Sciences Department | Allen Barnes | Davis | ambarnes@ucdavis.edu | 2015-01-28 |
| UCD-WFCB | University of California Davis Wildlife, Fish and Conservation Biology | Nann Fangue | Davis | | 2012-07-05 |
| UCD-WRTZ | University of California Davis Wuertz Lab | Alex Schriewer | Davis | aschriewer@ucdavis.edu | 2010-05-04 |
| ZALOM | University of California Davis, Zalom Entomology Laboratory | Dr. Frank Zalom | Davis | fgzalom@ucdavis.edu | 2007-09-01 |
| UCD-ALL | University of California Davis-Aquatic Limnology Lab | Tina Hammell | Davis | tlhammell@ucdavis.edu | 2007-09-01 |
| UCD-BML | University of California Davis-Bodega Marine Laboratory | | Bodega Bay | | 2017-05-12 |
| UCD-GC | University of California Davis-Granite Canyon | John Hunt | Monterey | jwhunt@ucdavis.edu | 2007-09-01 |
| UCD-HOBB | University of California Davis-Hobbs Laboratory | | Davis | | 2018-07-30 |
| UCD-LAWR | University of California Davis-LAWR | Randy Dahlgren | Davis | radahlgren@ucdavis.edu | 2007-09-01 |
| UCD-TERC | University of California Davis-Tahoe Environmental Research Center | | Incline Village | | 2013-05-06 |
| UCD-TATE | University of California Davis-Tate Laboratory | Kenneth W. Tate | Davis | | 2010-11-17 |
| UCSB | University of California Santa Barbara | Craig A. Carlson | Santa Barbara | carlson@lifesci.ucsb.edu | 2007-12-21 |
| UCSB-HOLDEN | University of California Santa Barbara - Holden Laboratory | | | holden@bren.ucsb.edu | 2019-10-21 |
| UCSB-VL | University of California Santa Barbara - Valentine Lab | David Valentine | Santa Barbara | valentine@ucsb.edu | 2025-05-09 |
| UCSC-BSOL | University of California Santa Cruz - Biological and Satellite Oceanography Lab | Dr. Raphael Kudela | Santa Cruz | kudela@ucsc.edu | 2026-04-07 |
| UCSC-CASFS | University of California Santa Cruz - Center for Agroecology and Sustainable Food Systems | | | | 2016-09-15 |
| UCSC-OL | University of California Santa Cruz - Division of Natural Sciences | Corinne Bacon | Santa Cruz | | 2007-12-21 |
| UCSC-DET | University of California Santa Cruz - Environmental Toxicology | Genine Scelfo | Santa Cruz | gms@earthsci.ucac.edu | 2007-12-21 |
| UCSC-IMS | University of California Santa Cruz - Institute of Marine Sciences | Cecile Mioni | | | 2011-06-27 |
| UCSC-Shenn | University of California Santa Cruz - Shennan Laboratories | | | | 2011-10-31 |
| UCD-AEAL | University of California-Aquatic Ecoystems Analysis Laboratory | Michael Johnson | Davis | mbjohnson@ucdavis.edu | 2007-09-01 |
| UCOB | University of Colorado Boulder | University of Colorado Boulder | | | 2008-04-24 |
| UGA | University of Georgia Atlanta | | | | 2015-05-19 |
| UIASL | University of Idaho Analytical Science Laboratory | | | | 2017-12-14 |
| UM-CES | University of Maryland Center for Environmental Science | Margaret A. Palmer | Solomons | palmer@cbl.umces.edu | 2007-12-21 |
| UM-AGNR | University of Maryland, College of Agriculture and Natural Resources | | | | 2012-04-30 |
| UM-HPEL | University of Maryland, Horn Point Environmental Laboratory | Jeffrey Alexander | Cambridge | jalexand@hpl.umces.edu | 2012-03-01 |
| UNR-NSPHL | University of Nevada, Reno - Nevada State Public Health Lab | | | | 2024-11-18 |
| USC | University of Southern California | | | | 2012-05-07 |
| USC-CL | University of Southern California-Caron Laboratory | | | | 2025-04-01 |
| UoT-RL | University of Toronto - Rochman Lab | Chelsea Rochman | Toronto | chelsea.rochman@utoronto.ca | 2018-04-26 |
| UU-EGI | University of Utah, Energy and Geoscience Institute | Theresa Lowe | Salt Lake City | tlowe@egi.utah.edu | 2007-12-21 |
| UWT-CUW | University of Washington, Tacoma - Center for Urban Waters | Dr. Ed Kolodziej | Tacoma | | 2026-01-22 |
| UWLC | University of Wisconsin - La Crosse | Dr. Mark Sandheinrich | La Crosse | sandhein.mark@uwlax.edu | 2012-08-30 |
| UFRWG | Upper Feather River Watershed Group | | | | 2011-08-25 |
| UMRWC | Upper Merced River Watershed Council | | | | 2011-05-05 |
| USLT_RCD | Upper Salinas-Las Tablas Resource Conservation District | Devin Best | | devin@us-ltrcd.org | 2018-05-10 |
| USGR EWMP Group | Upper San Gabriel River Enchanced Watershed Management Program Group | | | | 2016-03-10 |
| USMILG_TPG | Upper Santa Margarita Irrigated Lands Group | | | | 2020-05-22 |
| URS | URS Corporation | J. Edmund | Oakland | jody_edmund@urscorp.com | 2007-09-01 |
| USAF-CLINIC | US Air Force Clinic EMC. | | | | 2017-06-05 |
| USAF-MAFB | US Air Force McClellan Air Force Base | | | | 2017-06-05 |
| USAF-BROOKS | US AIR FORCE, Brooks Base Lab, Texas | | | | 2017-06-05 |
| USARMY-ORD | US Army Fort Ord | | | | 2017-06-05 |
| USDA | US Dept Of Agriculture | | | | 2017-06-08 |
| USEPA | US Environmental Protection Agency | | | | 2017-06-08 |
| USEPA-REGION8 | US Environmental Protection Agency Region 8 Laboratory, Colorado | | | | 2017-06-05 |
| USGS | US Geological Survey | | | | 2017-06-08 |
| USGS-EMAP | US Geological Survey Environmental Monitoring And Assessment Program | | | | 2017-06-08 |
| USGS-CWSC | US Geological Survey-Clean Water Science Center | Stephen Low | Santa Cruz | stephlow@usgs.gov | 2015-02-02 |
| USGS-Lawrence | US Geological Survey-District Water Quality Laboratory, Lawrence, KS | | | | 2017-06-05 |
| USGS-PFRG-OCRL | US Geological Survey-Pesticide Fate Research Group (PFRG), Organic Chemistry Research Laboratory (OCRL) | James Orlando | Sacramento | jorlando@usgs.gov | 2015-08-03 |
| USGS-Menlo | US Geological Survey-Water Resources-Menlo Park | Robin Stewart | Menlo Park | arstewar@usgs.gov | 2015-05-05 |
| USNPS | US National Park Service Water Resources Division | | | | 2017-06-08 |
| CIWQS 13831 | US Navy Naval Air Facility El Centro | | | | 1900-01-01 |
| USNAVY-PSL | US Navy Postgraduate School Lab | | | | 2017-06-05 |
| USNAVY-PWEEL | US Navy Public Works Environmental Engineering Lab | | | | 2017-06-05 |
| CIWQS 48447 | USDI Fish & Wildlife Service Coleman | | | | 1900-01-01 |
| CIWQS 48451 | USDI Fish & Wildlife Service Shasta Lake | | | | 1900-01-01 |
| CIWQS 31226 | USDI National Park Service Yosemite | | | | 1900-01-01 |
| CIWQS 48522 | USS-POSCO INDUSTRIES | | | | 1900-01-01 |
| USU-WCMAFE | Utah State University WCMAFE | Charles Hawkins | Logan | chuck.hawkins@usu.edu | 2015-01-26 |
| CIWQS 11176 | Vacaville City DPW | | | | 1900-01-01 |
| VALENT | Valent Lab | | | | 2017-06-05 |
| VSFCD | Vallejo Sanitation and Flood Control District | Doug Scott | Vallejo | | 2016-02-22 |
| CIWQS 48942 | Valley SD | | | | 1900-01-01 |
| VALLEY | Valley Toxicology Service | | | | 2017-06-05 |
| CIWQS 49654 | Valley Water Disposal Company | | | | 1900-01-01 |
| VCPWA | VCPWA-County Stormwater Program | | | | 2019-01-17 |
| CIWQS 11177 | Ventura City | | | | 1900-01-01 |
| VenturaCounty | Ventura County | | | | 2017-06-08 |
| VCEHD | Ventura County Environmental Health Division | Richard Hauge | Ventura | | 2012-05-07 |
| VCHCA | Ventura County HCA Laboratories | | | | 2012-05-07 |
| VCSQMP | Ventura County Stormwater Quality Monitoring Program | Kelly Haas | | | 2012-05-07 |
| VCWPD | Ventura County Watershed Protection District | | | | 2012-05-31 |
| VESTRA | VESTRA Resources, Inc. | | Redding | | 2011-09-29 |
| Viejas | Viejas Tribal Government | | Alpine | | 2024-05-07 |
| VIMS-DEAAH | Virigina Institute of Marine Science-Department of Environmental and Aquatic Animal Health | Mark J. La Guardia | Gloucester Point | markl@vims.edu | 2012-08-30 |
| CIWQS 8718 | Visalia City | | | | 1900-01-01 |
| VCE | Visalia City Engineering | | Visalia | | 2017-08-16 |
| VAL | Vista Analytical Laboratory | Anne Wilhoit | El Dorado Hills | awilhoit@vista-analytical.com | 2015-03-13 |
| VistaCity | Vista City | | | | 2014-07-02 |
| VistaIG | Vista Irrigation District | Don Smith | Vista | dsmith@vidwater.org | 2020-09-29 |
| CIWQS 49526 | VOPAK Terminal Los Angeles Inc | | | | 1900-01-01 |
| WRID | Walker River Irrigation District | | | | 2023-07-12 |
| CIWQS 50246 | Washington/Niagara Mining Ptnr | | | | 1900-01-01 |
| DFW-WPCL | Water Pollution Control Lab - DFW | | | | 2014-02-26 |
| WTCL | Water Testing & Consulting Laboratory | | | | 2017-06-05 |
| CIWQS 50305 | Watsonville City | | | | 1900-01-01 |
| WWW | Watsonville Wetlands Watch | Emily Howard | Watsonville | Emily@watsonvillewetlandswatch.org | 2021-05-03 |
| WKL | Weck Laboratories, Inc. | Jayna Kostura | Industry | jkostura@wecklabs.com | 2007-09-01 |
| WCAL | West Coast Analytical Service, Santa Fe | | | | 2017-06-05 |
| WCILP | Westcoast Coalition for Irrigated Lands Program | Joe McGahan | Los Banos | jmcgahan@summerseng.com | 2007-09-01 |
| WAL | Western Agricultural Laboratory | | | | 2017-06-05 |
| WAL_Chino | Western Agricultural Laboratory, Chino | | | | 2017-06-05 |
| WETLAB | Western Environmental Testing Laboratory | | | | 2015-06-11 |
| CIWQS 517405 | Western Riverside County Regional Wastewater Authority | | | | 1900-01-01 |
| WSRCD | Western Shasta RCD | | Anderson | wsrcd@westernshastarcd.org | 2014-02-18 |
| WSC | Westlands Stormwater Coalition | Susan Ramos, Orvil McKinnis | Fresno | sramos@westlandswater.org | 2009-09-24 |
| WWD | Westlands Water District | | | | 2011-05-12 |
| CIWQS 51663 | Westmorland City | | | | 1900-01-01 |
| WestonSolu | Weston Solutions | Lisa Marie Kay | Carlsbad | | 2007-09-01 |
| WSJRWC | Westside San Joaquin River Watershed Coalition | Joseph McGahan | Hanford | jmcgahan@summerseng.com | 2009-09-24 |
| WWQC | Westside Water Quality Coalition | Greg Hammet | McKittrick | ghammett@belridgewsd.com | 2014-07-09 |
| WRA | Wetlands Research Associates | Kari Dupler | San Rafael | dupler@wra-ca.com | 2018-01-10 |
| CIWQS 50761 | Wheelabrator Shasta Energy Co | | | | 1900-01-01 |
| WRMWSD | Wheeler Ridge-Maricopa Water Storage District | | Bakersfield | | 2019-04-30 |
| Wildlands | Wildlands, Inc. | | Rocklin | | 2015-11-02 |
| WLDC | Wildomar City | | Wildomar | | 2018-01-30 |
| WRS | Willamette Research Station | | Corvallis | | 2013-09-26 |
| CIWQS 523730 | Williams City | | | | 1900-01-01 |
| CIWQS 50967 | Willits City | | | | 1900-01-01 |
| CIWQS 50978 | Willows City | | | | 1900-01-01 |
| WFI | Windset Farms, Inc. | | | | 2018-01-12 |
| CIWQS 51027 | Windsor Water District | | | | 1900-01-01 |
| Windward | Windward Environmental LLC | | Seattle | 206-378-1364 | 2025-03-12 |
| WITZKE | Witzke Lab | | | | 2017-06-05 |
| WCCA | Wolf Creek Community Aliance | | Grass Valley | wolf@wolfcreekalliance.org | 2017-04-25 |
| WoodAquaticTox | Wood Aquatic Toxicology Laboratory | | San Diego | | 2019-08-16 |
| WoodGroup | Wood Group, Inc. | Luis De La Torre | San Diego | luis.delatorre@woodplc.com | 2018-03-05 |
| WoodMolec | Wood Molecular Services Lab | Darcy McCargar | San Diego | | 2020-04-22 |
| WOODARDCURRAN | Woodard & Curran | | | | 2019-05-03 |
| CIWQS 51158 | Woodland City | | | | 1900-01-01 |
| WoRMS | World Register of Marine Species | | | | 1900-01-01 |
| WRECO | Wreco | | Walnut Creek | | 2016-06-28 |
| WSU | Wright State University | | Dayton | | 2016-12-07 |
| WSPAquaticToxSD | WSP Aquatic Toxicology Laboratory San Diego | | | | 2022-12-13 |
| WSP_SD_MSL | WSP San Diego Molecular Services Laboratory | Darcy McCargar | San Diego | darcy.ebentier@wsp.com | 2022-12-19 |
| WSP_SD_SkyPkwy | WSP San Diego Sky Parkway | Teresa Perone | San Diego | teresa.perone@wsp.com | 2022-10-13 |
| YoloCounty | Yolo County | | | | 2017-06-08 |
| CIWQS 52191 | Yountville, Town of | | | | 1900-01-01 |
| CIWQS 52205 | Yuba City | | | | 1900-01-01 |
| YubaCounty | Yuba County | | | | 2017-06-08 |
| CIWQS 356893 | Yucaipa Valley Water Dist | | | | 1900-01-01 |
| Yurok-Tribe | Yurok Tribal Environmental Program | Kassandra Grimm | Klamath | kgrimm@yuroktribe.nsn.us | 2012-04-20 |
| ZALCO | Zalco Laboratories, Inc. | | | | 2017-06-05 |
| ZENECA | Zeneca Lab | | | | 2017-06-05 |
| Zone7 | Zone 7 Water Agency | Tami Church | Livermore | tchurch@zone7water.com | 2017-03-09 |
| ZYMAX | Zymax Envirotechnology | | | | 2017-06-05 |