State drinking water records
California drinking water systems
2,931 community water systems serve California and are listed below under 58 counties and on the pages of 1,397 cities and towns. Their own population figures add up to 44,167,025 people, a sum that counts people twice where one system sells water to another.
942 of them (32%) had at least one health-based violation in the last 10 years. 633 systems still have one unresolved.
2,065 rely mainly on groundwater and 865 on surface water, counting water bought from other systems.
2,603 systems filed a lead service line inventory listing 14 lead lines, 11,312 galvanized lines that must be replaced and 833,126 lines of unknown material.
116 systems are placed by mailing address or by the county their records name: EPA has no service area map for 97 of them, and 19 have one that does not line up with their own records.
- Community water systems
- 2,931
- People served, sum of each system's own figure
- 44,167,025
- Systems with a health-based violation, last 10 years
- 942
- Systems with one unresolved
- 633
- Lead service lines in inventories
- 14
Counties
58 countiesEach county counts the systems whose service area map reaches it. Systems placed only by a mailing address are listed on the county pages but not counted here.
| County | Systems | People served | With a health-based violation, 10 years | With one unresolved |
|---|---|---|---|---|
| Alameda County | 13 | 2,226,756 | 1 | 1 |
| Alpine County | 4 | 8,701 | 2 | 0 |
| Amador County | 22 | 45,645 | 8 | 5 |
| Butte County | 41 | 197,752 | 16 | 17 |
| Calaveras County | 19 | 50,864 | 8 | 4 |
| Colusa County | 11 | 21,085 | 1 | 3 |
| Contra Costa County | 41 | 2,101,782 | 10 | 8 |
| Del Norte County | 17 | 25,815 | 7 | 8 |
| El Dorado County | 19 | 267,573 | 3 | 1 |
| Fresno County | 102 | 977,784 | 45 | 22 |
| Glenn County | 14 | 22,441 | 2 | 2 |
| Humboldt County | 49 | 126,581 | 16 | 12 |
| Imperial County | 31 | 177,668 | 20 | 12 |
| Inyo County | 49 | 20,682 | 13 | 15 |
| Kern County | 167 | 932,356 | 63 | 27 |
| Kings County | 14 | 150,820 | 6 | 6 |
| Lake County | 45 | 66,833 | 14 | 11 |
| Lassen County | 16 | 18,945 | 2 | 3 |
| Los Angeles County | 196 | 13,928,626 | 36 | 30 |
| Madera County | 65 | 127,695 | 34 | 12 |
| Marin County | 15 | 276,967 | 3 | 2 |
| Mariposa County | 12 | 9,792 | 4 | 4 |
| Mendocino County | 50 | 63,632 | 18 | 15 |
| Merced County | 22 | 240,326 | 14 | 11 |
| Modoc County | 8 | 5,927 | 4 | 4 |
| Mono County | 19 | 18,819 | 8 | 7 |
| Monterey County | 158 | 442,610 | 52 | 48 |
| Napa County | 28 | 128,683 | 16 | 12 |
| Nevada County | 21 | 94,410 | 7 | 3 |
| Orange County | 39 | 3,179,173 | 3 | 2 |
| Placer County | 52 | 446,101 | 4 | 3 |
| Plumas County | 27 | 24,736 | 13 | 10 |
| Riverside County | 101 | 2,676,046 | 25 | 16 |
| Sacramento County | 62 | 1,618,462 | 16 | 15 |
| San Benito County | 30 | 61,097 | 11 | 5 |
| San Bernardino County | 144 | 2,381,948 | 38 | 28 |
| San Diego County | 95 | 3,549,710 | 34 | 16 |
| San Francisco County | 3 | 855,383 | 0 | 0 |
| San Joaquin County | 93 | 741,611 | 18 | 6 |
| San Luis Obispo County | 71 | 268,460 | 18 | 3 |
| San Mateo County | 35 | 779,338 | 8 | 1 |
| Santa Barbara County | 63 | 464,845 | 10 | 6 |
| Santa Clara County | 66 | 2,075,952 | 19 | 12 |
| Santa Cruz County | 51 | 252,863 | 21 | 12 |
| Shasta County | 60 | 168,707 | 30 | 22 |
| Sierra County | 8 | 3,530 | 3 | 1 |
| Siskiyou County | 32 | 28,673 | 19 | 16 |
| Solano County | 26 | 510,348 | 7 | 4 |
| Sonoma County | 127 | 441,259 | 33 | 22 |
| Stanislaus County | 57 | 488,430 | 18 | 8 |
| Sutter County | 8 | 83,115 | 3 | 0 |
| Tehama County | 48 | 36,198 | 27 | 27 |
| Trinity County | 17 | 9,591 | 11 | 10 |
| Tulare County | 93 | 433,362 | 52 | 31 |
| Tuolumne County | 48 | 63,604 | 13 | 14 |
| Ventura County | 69 | 872,422 | 18 | 10 |
| Yolo County | 19 | 260,925 | 7 | 5 |
| Yuba County | 22 | 76,516 | 5 | 3 |
Largest systems
| System | Main county | People served | Main source | Health-based violations, 10 years | Unresolved | Lead lines |
|---|---|---|---|---|---|---|
| Los Angeles-City, Dept. of Water & Power | Los Angeles County | 7,751,132 | Surface water | 1 | 0 | 0 |
| East Bay MUD | Contra Costa County and 1 other county | 1,442,800 | Surface water | 0 | 0 | 0 |
| City of San Diego | San Diego County | 1,385,379 | Surface water | 0 | 0 | 0 |
| San Jose Water | Santa Clara County | 1,039,920 | Surface water | 1 | 0 | 0 |
| Sfpuc City Distribution Division | San Francisco County | 848,019 | Purchased surface water | 0 | 0 | 0 |
| Eastern Municipal WD | Riverside County | 666,581 | Purchased surface water | 0 | 0 | 0 |
| City of Fresno | Fresno County | 545,716 | Surface water | 0 | 0 | 0 |
| City of Sacramento Main | Sacramento County | 527,979 | Surface water | 0 | 0 | 0 |
| Long Beach Utilities Department | Los Angeles County | 466,772 | Purchased surface water | 0 | 0 | 0 |
| Irvine Ranch Water District | Orange County | 444,800 | Surface water | 0 | 0 | 0 |
| City of Anaheim | Orange County | 348,593 | Surface water | 0 | 0 | 0 |
| Alameda County Water District | Alameda County | 344,000 | Surface water | 0 | 0 | 0 |
| City of Santa Ana | Orange County | 310,539 | Purchased surface water | 0 | 0 | 0 |
| City of Riverside | Riverside County | 298,398 | Groundwater under direct influence | 0 | 0 | 0 |
| Santa Clarita Valley Water Agency | Los Angeles County | 294,090 | Surface water | 0 | 0 | 0 |
Systems with unresolved health-based violations
633 systemsThe 100 with the most unresolved violations are listed. The county pages list the other 533.
| System | Main county | People served | Main source | Health-based violations, 10 years | Unresolved | Lead lines |
|---|---|---|---|---|---|---|
| Utu Utu Gwaitu Paiute Tribe | Mono County | 222 | Groundwater | 14 | 26 | 0 |
| Havasu Water Company | San Bernardino County | 361 | Surface water | 28 | 22 | 0 |
| Toledo MHP | Riverside County | 68 | Groundwater | 5 | 22 | 0 |
| Tule River Reservation Main | Tulare County | 2,560 | Surface water | 15 | 15 | 0 |
| Torres-Martinez Clinic | Riverside County | 379 | Purchased groundwater | 0 | 13 | 0 |
| Big River Development | San Bernardino County | 3,550 | Groundwater | 3 | 12 | 0 |
| DD Mobile Home Park | Imperial County | 300 | Groundwater | 12 | 11 | 0 |
| Redding Rancheria | Shasta County | 2,015 | Purchased surface water | 1 | 10 | No inventory |
| Grindstone Rancheria | Tehama County | 150 | Surface water | 94 | 9 | 0 |
| Quechan Utility | Imperial County | 5,660 | Groundwater | 3 | 8 | 0 |
| Middletown Rancheria Community Water System | Lake County | 487 | Purchased groundwater | 1 | 4 | 0 |
| Pleasant Grove MHP | Butte County | 327 | Groundwater | 1 | 4 | No inventory |
| Bar-Len MWC | San Bernardino County | 126 | Groundwater | 39 | 4 | 0 |
| Clark Street Community Well | Kern County | 90 | Groundwater | 2 | 4 | No inventory |
| Round Valley Agency | Mendocino County | 84 | Groundwater | 3 | 4 | 0 |
| Arviso - Mobile Home Park | San Diego County | 70 | Groundwater | 1 | 4 | 0 |
| Turner Trailer Park | San Diego County | 70 | Purchased groundwater | 1 | 4 | 0 |
| Maher Rd WS #05 | Monterey County | 48 | Groundwater | 0 | 4 | 0 |
| Tierra Verde MWC | Monterey County | 48 | Groundwater | 0 | 4 | 0 |
| Cold Springs Subdivision | Fresno County | 35 | Groundwater | 3 | 4 | 0 |
| Yosemite Spring Park Util Co | Madera County | 5,300 | Groundwater | 13 | 3 | 0 |
| Cobb Area County Water District | Lake County | 3,515 | Groundwater | 1 | 3 | 0 |
| Richgrove Community Services District | Tulare County | 1,617 | Groundwater | 8 | 3 | No inventory |
| Willow Creek C.S.D. | Humboldt County | 1,298 | Groundwater under direct influence | 2 | 3 | 0 |
| Sea Ranch Water Company,The (Puc) | Sonoma County | 1,160 | Surface water | 1 | 3 | No inventory |
| Bakman Water-Rolling Hills | Madera County | 1,107 | Groundwater | 2 | 3 | No inventory |
| City of Tulelake | Modoc County and 1 other county | 856 | Groundwater | 1 | 3 | 0 |
| Plainview Mutual Water Company | Tulare County | 617 | Groundwater | 1 | 3 | 0 |
| Knoll Enterprises | San Bernardino County | 500 | Groundwater | 71 | 3 | No inventory |
| Glen Martin MWC | San Bernardino County | 450 | Groundwater | 1 | 3 | 0 |
| Big Sandy Rancheria | Fresno County | 408 | Groundwater | 4 | 3 | 0 |
| Forest Park MWC | San Bernardino County | 406 | Groundwater | 1 | 3 | 0 |
| Leisure Pines Mutual Water Co | Tuolumne County | 340 | Groundwater | 1 | 3 | 0 |
| Yurok - Terwer Water System | Del Norte County | 300 | Groundwater | 0 | 3 | 0 |
| Bar H MWC | San Bernardino County | 260 | Groundwater | 14 | 3 | No inventory |
| Hess Winery | Napa County | 250 | Groundwater | 1 | 3 | No inventory |
| Casitas Mutual Water Company | Ventura County | 238 | Purchased surface water | 1 | 3 | 0 |
| Yurok - Requa | Humboldt County | 215 | Groundwater | 0 | 3 | 0 |
| Capell Valley Estates | Napa County | 208 | Surface water | 1 | 3 | 0 |
| Twain Harte Valley MWC | Tuolumne County | 202 | Surface water | 1 | 3 | 0 |
| Gordon Acres Water Co | San Bernardino County | 200 | Groundwater | 14 | 3 | No inventory |
| Randal's Ranchette Mutual Water Company | Sonoma County | 200 | Groundwater | 1 | 3 | No inventory |
| Alpine Springs Mobile Home Park | Los Angeles County | 175 | Groundwater | 1 | 3 | 0 |
| Stone Creek Water Company | Riverside County | 152 | Groundwater | 1 | 3 | No inventory |
| Siskiyou Co.Service Area #5/Carrick | Siskiyou County | 143 | Groundwater | 1 | 3 | No inventory |
| Maywood Mobile Home Park | Tehama County | 140 | Groundwater | 1 | 3 | No inventory |
| Kern Valley Mutual Water Company | Kern County | 132 | Groundwater | 2 | 3 | No inventory |
| Camphora Apartments | Monterey County | 126 | Groundwater | 0 | 3 | 0 |
| Creekside Cabins & RV Resort | Mendocino County | 124 | Groundwater | 1 | 3 | No inventory |
| Fort Independence | Inyo County | 120 | Groundwater | 0 | 3 | 0 |
| Sugar Pine Homeowners Assoc | Madera County | 120 | Groundwater | 1 | 3 | 0 |
| Hi Desert MWC | San Bernardino County | 112 | Groundwater | 7 | 3 | No inventory |
| Robley Property MWS | Monterey County | 92 | Groundwater | 0 | 3 | 0 |
| Creekside Mobilehome Park | Shasta County | 85 | Groundwater | 1 | 3 | 0 |
| Sierra East HOA | Mono County | 84 | Groundwater | 22 | 3 | 0 |
| Yokayo Tribe of Indians | Mendocino County | 75 | Groundwater | 1 | 3 | No inventory |
| Apple Ave WS #02 | Monterey County | 75 | Groundwater | 1 | 3 | No inventory |
| Woodside WA | Monterey County | 73 | Groundwater | 0 | 3 | 0 |
| Hidden Harbor Marina & RVP | Tehama County | 70 | Groundwater | 1 | 3 | No inventory |
| Mineral Mountain Mutual Water | Calaveras County | 67 | Groundwater | 1 | 3 | 0 |
| River Rd WS #25 | Monterey County | 65 | Groundwater | 34 | 3 | 0 |
| Bucktail Mutual Water Company | Trinity County | 42 | Groundwater | 1 | 3 | No inventory |
| The River Community | Los Angeles County | 35 | Groundwater | 1 | 3 | No inventory |
| Rivers End Trailer Park | Los Angeles County | 35 | Groundwater | 1 | 3 | 0 |
| Two Twenty Four Mobile Home Pk | Madera County | 35 | Groundwater | 26 | 3 | 0 |
| La Cienega MHP | Riverside County | 30 | Groundwater | 0 | 3 | 0 |
| Spring Mountain Mutual Water Company | Kern County | 26 | Groundwater | 15 | 3 | 0 |
| Antoinette Mutual Water Co | Tehama County | 25 | Groundwater | 1 | 3 | 0 |
| Plantation Mobile Home Park | Sacramento County | 22 | Groundwater | 0 | 3 | 0 |
| Robinson's Corner MHP | Butte County | 20 | Groundwater | 2 | 3 | No inventory |
| Scwa - Laguna/Vineyard | Sacramento County | 184,896 | Surface water | 1 | 2 | No inventory |
| City of Fairfield | Solano County | 120,377 | Surface water | 1 | 2 | 0 |
| City of Porterville | Tulare County | 63,487 | Groundwater | 1 | 2 | No inventory |
| Monterey Park-City, Water Dept. | Los Angeles County | 62,183 | Groundwater | 1 | 2 | 0 |
| City of Ceres | Stanislaus County | 54,513 | Purchased surface water | 1 | 2 | No inventory |
| City of West Sacramento | Yolo County | 53,355 | Surface water | 1 | 2 | No inventory |
| City of Calexico | Imperial County | 40,357 | Purchased surface water | 2 | 2 | No inventory |
| East Niles CSD | Kern County | 32,517 | Purchased surface water | 3 | 2 | 0 |
| Scwa Mather-Sunrise | Sacramento County | 30,825 | Purchased surface water | 1 | 2 | No inventory |
| Calif State Polytechnical Univ - Pomona | Los Angeles County | 29,854 | Surface water | 3 | 2 | 0 |
| Suisun-Solano Water Authority | Solano County | 29,105 | Surface water | 11 | 2 | 0 |
| Pechanga | San Diego County | 29,100 | Purchased surface water | 0 | 2 | 0 |
| City of Dinuba | Tulare County | 27,281 | Groundwater | 1 | 2 | 0 |
| San Lorenzo Valley Water Dist | Santa Cruz County | 21,145 | Surface water | 1 | 2 | 0 |
| Arvin Community Services Dist | Kern County | 19,669 | Groundwater | 13 | 2 | No inventory |
| Bakman Water Company | Fresno County | 17,393 | Groundwater | 1 | 2 | 0 |
| City of Livingston | Merced County | 14,894 | Groundwater | 2 | 2 | 0 |
| City of Parlier | Fresno County | 14,576 | Groundwater | 1 | 2 | No inventory |
| Pala North | San Diego County | 14,280 | Groundwater | 13 | 2 | 0 |
| City of Avenal | Kings County | 13,696 | Surface water | 7 | 2 | No inventory |
| City of Anderson | Shasta County | 11,147 | Groundwater | 1 | 2 | 0 |
| City of Farmersville | Tulare County | 10,243 | Groundwater | 1 | 2 | No inventory |
| Scwa - Arden Park Vista | Sacramento County | 10,101 | Groundwater | 1 | 2 | No inventory |
| Winton Water & Sanitary Dist | Merced County | 9,745 | Groundwater | 1 | 2 | 0 |
| City of Orange Cove | Fresno County | 9,525 | Surface water | 1 | 2 | 0 |
| City of Tehachapi | Kern County | 9,094 | Groundwater | 1 | 2 | 0 |
| City of Yreka | Siskiyou County | 7,825 | Surface water | 1 | 2 | No inventory |
| Earlimart PUD | Tulare County | 7,679 | Groundwater | 1 | 2 | No inventory |
| Folsom State Prison | Sacramento County | 7,502 | Surface water | 1 | 2 | No inventory |
| City of Hughson | Stanislaus County | 7,481 | Groundwater | 36 | 2 | 0 |
Counties come from the counties EPA lists each system serving, matched to 2024 Census counties; where EPA lists none, from the county coded in the system's ID, its service area map, or its mailing address. A county holding at least a fifth of a system's service area map is added when at least a fifth of that map lies in those counties. Towns are the ones EPA lists and the Census places such a map covers, always inside those counties. In New England, where EPA's town names a whole Town, it is not matched to the village of the same name. A system is not listed in a county holding less than a fifth of its map, or in a county or town its map reaches when the map lies mostly outside the counties EPA lists, so a page can leave out a system that serves part of the area. Methodology and limitations