All water systems in California
7,380 systems
| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Riverbank, City of Riverbank · Stanislaus County |
25,625 | 0 | 0 | |
|
Windsor, Town of Sonoma County |
25,561 | 0 | 0 | |
|
Sunnyslope County Water Dist San Benito County |
25,486 | 0 | 0 | |
|
City of South Pasadena South Pasadena · Los Angeles County |
25,329 | 0 | 0 | |
|
Sunny Slope Water Co. Los Angeles County |
25,252 | 1 | 1 | |
|
Loma Linda, City of Loma Linda · San Bernardino County |
25,208 | 0 | 0 | |
|
Norco, City of Norco · Riverside County |
25,068 | 5 | 0 | |
|
Antelope Valley Poppy Reserve State Park Los Angeles County |
25,007 | 0 | 0 | |
|
Orchard Dale Water District Los Angeles County |
25,000 | 0 | 0 | |
|
Patterson, City of Patterson · Stanislaus County |
24,977 | 0 | 0 | |
|
City of Seal Beach Seal Beach · Orange County |
24,937 | 0 | 0 | |
|
Cal-Am Water Company Duarte Los Angeles County |
24,767 | 0 | 0 | |
|
Liberty Utilities Lynwood Los Angeles County |
24,649 | 0 | 0 | |
|
LA Cocina Riverside County |
24,524 | 0 | 0 | |
|
Phelan Pinon Hills Csd San Bernardino County |
24,509 | 0 | 0 | |
|
Stanford University Santa Clara County |
23,817 | 0 | 0 | |
|
Golden State Water Company Bay Point Contra Costa County |
23,765 | 0 | 0 | |
|
Rainbow Municipal WD San Diego County |
23,536 | 0 | 0 | |
|
San Fernando-City, Water Dept. San Fernando · Los Angeles County |
23,364 | 0 | 0 | |
|
Oakdale, City of Oakdale · Stanislaus County |
23,235 | 1 | 0 | |
|
Valley of the Moon Water District Sonoma County |
23,140 | 0 | 0 | |
|
EL Monte-City, Water Dept. El Monte · Los Angeles County |
23,000 | 0 | 0 | |
|
Corcoran, City of Corcoran · Kings County |
22,808 | 0 | 0 | |
|
City of Millbrae Millbrae · San Mateo County |
22,795 | 1 | 0 | |
|
Wasco, City of Wasco · Kern County |
22,757 | 0 | 0 | |
|
South Feather W&p Miners Ranch Butte County |
22,638 | 0 | 0 | |
|
Menlo Park Municipal Water Menlo Park · San Mateo County |
22,362 | 0 | 0 | |
|
Temescal Valley Water District Riverside County |
22,268 | 1 | 0 | |
|
Csp-Fremont Peak San Benito County |
22,217 | 0 | 0 | |
|
Imperial, City of Imperial · Imperial County |
22,102 | 2 | 1 | |
|
Pico WD Los Angeles County |
22,051 | 0 | 0 | |
|
Shafter, City of Shafter · Kern County |
21,915 | 0 | 0 | |
|
Linda County Water District Yuba County |
21,654 | 0 | 0 | |
|
Port Hueneme City Water Dept Ventura County |
21,582 | 1 | 0 | |
|
Santa FE I.d. San Diego County |
21,539 | 0 | 0 | |
|
San Lorenzo Valley Water Dist Santa Cruz County |
21,513 | 1 | 1 | |
|
San Jacinto, City of San Jacinto · Riverside County |
20,938 | 0 | 0 | |
|
Cal/am Water Company Baldwin Hills Los Angeles County |
20,724 | 0 | 0 | |
|
West Kern Water District Kern County |
20,585 | 0 | 0 | |
|
Norwalk City, Water Dept. Norwalk · Los Angeles County |
20,283 | 1 | 1 | |
|
Lomita-City, Water Dept. Lomita · Los Angeles County |
20,256 | 0 | 0 | |
|
Humboldt C.s.d. Humboldt County |
19,775 | 2 | 1 | |
|
Soledad, City of Soledad · Monterey County |
19,732 | 0 | 0 | |
|
Arvin Community Services Dist Kern County |
19,669 | 1 | 1 | |
|
California Water Service CO Westlake Ventura County |
19,544 | 0 | 0 | |
|
Quartz Hill Water Dist. Los Angeles County |
19,322 | 0 | 0 | |
|
Santa FE Springs City, Water Dept. Santa Fe Springs · Los Angeles County |
19,219 | 0 | 0 | |
|
Lamont Public Utility Dist Kern County |
19,057 | 0 | 0 | |
|
Riverside Highland Water Company San Bernardino County |
19,053 | 1 | 1 | |
|
Coastside County Water District San Mateo County |
19,033 | 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 currently 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.