All water systems in California
7,380 systems
| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
California Water Service San Carlos San Mateo County |
34,801 | 0 | 0 | |
|
Robinson Creek Campground Mono County |
34,742 | 0 | 0 | |
|
Golden State Water Company Orcutt Santa Barbara County |
34,267 | 1 | 0 | |
|
Manhattan Beach-City, Water Dept. Manhattan Beach · Los Angeles County |
34,051 | 0 | 0 | |
|
Hemet, City of Hemet · Riverside County |
33,591 | 0 | 0 | |
|
Atascadero Mutual Water CO San Luis Obispo County |
33,307 | 0 | 0 | |
|
Covina-City, Water Dept. Covina · Los Angeles County |
33,300 | 0 | 0 | |
|
Scwa Mather-Sunrise Sacramento County |
32,812 | 1 | 1 | |
|
Camrosa Water District Ventura County |
32,700 | 0 | 0 | |
|
East Niles Csd Kern County |
32,517 | 2 | 1 | |
|
City of Burlingame Burlingame · San Mateo County |
32,453 | 0 | 0 | |
|
Golden State Water CO Barstow San Bernardino County |
32,445 | 0 | 0 | |
|
City of Santa Paula Ventura County |
31,786 | 0 | 0 | |
|
Banning, City of Banning · Riverside County |
31,680 | 0 | 0 | |
|
LA Verne, City WD La Verne · Los Angeles County |
31,334 | 0 | 0 | |
|
Los Angeles Cwwd 29 & 80-Malibu Los Angeles County |
31,316 | 0 | 0 | |
|
City of Paso Robles Water Division San Luis Obispo County |
31,176 | 0 | 0 | |
|
Mid-Peninsula Water District San Mateo County |
31,059 | 0 | 0 | |
|
City of Martinez Martinez · Contra Costa County |
31,015 | 0 | 0 | |
|
Valley Center Mwd San Diego County |
30,166 | 0 | 0 | |
|
South Tahoe Pud Main El Dorado County |
30,089 | 0 | 0 | |
|
Boulder Creek Trailer Park Inyo County |
30,000 | 0 | 0 | |
|
San Juan Water District Sacramento County |
29,738 | 0 | 0 | |
|
City of East Palo Alto East Palo Alto · San Mateo County |
29,519 | 0 | 0 | |
|
City of Atwater Atwater · Merced County |
29,479 | 0 | 0 | |
|
Suisun-Solano Water Authority Solano County |
29,105 | 2 | 1 | |
|
Pechanga County |
29,100 | 1 | 1 | |
|
Rincon del Diablo Mwd (id-1) San Diego County |
28,427 | 0 | 0 | |
|
Crescenta Valley Cwd Los Angeles County |
28,162 | 0 | 0 | |
|
Vernon-City, Water Dept. Vernon · Los Angeles County |
28,112 | 0 | 0 | |
|
Dinuba, City of Dinuba · Tulare County |
27,641 | 1 | 1 | |
|
Cws North Garden Kern County |
27,634 | 0 | 0 | |
|
Gswc-South Arcadia Los Angeles County |
27,430 | 0 | 0 | |
|
Placer Cwa Auburn/bowman Placer County |
27,317 | 0 | 0 | |
|
Lemoore, City of Lemoore · Kings County |
27,185 | 3 | 1 | |
|
City of Benicia Benicia · Solano County |
27,131 | 0 | 0 | |
|
Eureka, City of Eureka · Humboldt County |
27,078 | 0 | 0 | |
|
Brawley, City of Brawley · Imperial County |
26,862 | 1 | 0 | |
|
HI Desert WD San Bernardino County |
26,660 | 1 | 1 | |
|
San Diego Mountain Lodge San Diego County |
26,641 | 3 | 0 | |
|
Hollister, City of Hollister · San Benito County |
26,598 | 1 | 0 | |
|
Montebello Land & Water Co. Los Angeles County |
26,554 | 1 | 0 | |
|
Galt, City of Galt · Sacramento County |
26,536 | 0 | 0 | |
|
Gswc-South San Gabriel Los Angeles County |
26,451 | 0 | 0 | |
|
City of Mountain House San Joaquin County |
26,400 | 0 | 0 | |
|
City of Sanger Sanger · Fresno County |
26,357 | 1 | 0 | |
|
Liberty Utilities Compton Los Angeles County |
26,316 | 0 | 0 | |
|
Big Bear Lake Dwp Big Bear System San Bernardino County |
26,164 | 0 | 0 | |
|
Reedley, City of Reedley · Fresno County |
26,076 | 0 | 0 | |
|
Cws Selma Fresno County |
25,651 | 0 | 0 |
About this data
Rules violated counts the rules a system was in violation of in the past three years, including monitoring and reporting lapses; one rule can carry several violations. Unresolved is the number of those rules still in violation at EPA's latest data refresh.
Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The California records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.