All water systems in California
7,380 systems
| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Cerritos City, Water Dept. Cerritos · Los Angeles County |
46,851 | 1 | 1 | |
|
Colton, City of Colton · San Bernardino County |
46,525 | 0 | 0 | |
|
Bellflower Somerset Mwc Los Angeles County |
46,300 | 0 | 0 | |
|
Hawthorne-City Water Dept. Hawthorne · Los Angeles County |
46,039 | 0 | 0 | |
|
Oildale Mwc Kern County |
45,315 | 2 | 1 | |
|
Golden State Water Company Simi Valley Ventura County |
45,086 | 0 | 0 | |
|
Camp Pendleton (south) San Diego County |
44,555 | 0 | 0 | |
|
Glendora-City, Water Dept. Glendora · Los Angeles County |
44,411 | 0 | 0 | |
|
EL Centro, City of El Centro · Imperial County |
44,124 | 0 | 0 | |
|
Elk Grove Water District Sacramento County |
44,065 | 0 | 0 | |
|
Rohnert Park, City of Rohnert Park · Sonoma County |
43,821 | 0 | 0 | |
|
Coachella Water Authority Coachella · Riverside County |
43,590 | 2 | 0 | |
|
Mission Springs WD Riverside County |
43,484 | 0 | 0 | |
|
Gswc Norwalk Los Angeles County |
43,167 | 0 | 0 | |
|
City of San Bruno San Bruno · San Mateo County |
42,631 | 0 | 0 | |
|
San Francisco International Airport San Francisco County |
42,400 | 0 | 0 | |
|
Indian Wells Valley W.d. Kern County |
41,474 | 0 | 0 | |
|
South Coast Water District Orange County |
41,194 | 0 | 0 | |
|
Carmichael Water District Sacramento County |
41,193 | 2 | 0 | |
|
Soquel Creek Water District Santa Cruz County |
40,962 | 0 | 0 | |
|
Lompoc-City Water Utility Div Lompoc · Santa Barbara County |
40,538 | 0 | 0 | |
|
San Dieguito WD San Diego County |
40,405 | 1 | 0 | |
|
Calexico, City of Calexico · Imperial County |
40,357 | 1 | 1 | |
|
San Gabriel County WD Los Angeles County |
40,154 | 0 | 0 | |
|
Lake Cachuma County Park Santa Barbara County |
40,019 | 0 | 0 | |
|
Adelanto, City of Adelanto · San Bernardino County |
39,930 | 1 | 0 | |
|
Beverly Hills-City, Water Dept. Beverly Hills · Los Angeles County |
39,922 | 0 | 0 | |
|
Gswc Claremont Los Angeles County |
39,776 | 0 | 0 | |
|
Pico Rivera City, Water Dept. Pico Rivera · Los Angeles County |
39,451 | 0 | 0 | |
|
Marina Coast Water District Monterey County |
38,918 | 0 | 0 | |
|
City of Livermore Livermore · Alameda County |
38,892 | 0 | 0 | |
|
City of Lathrop Lathrop · San Joaquin County |
38,596 | 0 | 0 | |
|
North Coast County Water Dist San Mateo County |
38,546 | 0 | 0 | |
|
Rubidoux Community SD Riverside County |
38,522 | 1 | 0 | |
|
Gswc Culver City Santa Fe Springs · Los Angeles County |
38,233 | 0 | 0 | |
|
Tejon Castac WD I5 & Laval RD Kern County |
38,125 | 0 | 0 | |
|
Monrovia-City, Water Dept. Monrovia · Los Angeles County |
37,931 | 0 | 0 | |
|
Antelope Valley E Kern Wtr Agy-Rosamond Kern County |
37,634 | 0 | 0 | |
|
Vaughn WC INC Kern County |
37,189 | 0 | 0 | |
|
Truckee-Donner Pud, Main Nevada County |
36,730 | 0 | 0 | |
|
Estero Municipal Improvement District San Mateo County |
36,556 | 0 | 0 | |
|
Ramona Municipal WD San Diego County |
36,455 | 0 | 0 | |
|
Fair Oaks Water District Sacramento County |
36,226 | 0 | 0 | |
|
Aguanga Market Water System Riverside County |
36,012 | 0 | 0 | |
|
Cal AM Antelope Sacramento County |
35,617 | 0 | 0 | |
|
Ventura Cwwd No. 1 Moorpark Ventura County |
35,514 | 0 | 0 | |
|
Lakeside WD San Diego County |
35,500 | 1 | 0 | |
|
Santa Margarita Water District-Id9 San Juan Capistrano · Orange County |
35,309 | 0 | 0 | |
|
Fallbrook Pud San Diego County |
35,237 | 0 | 0 | |
|
Pokonobe Lodge Restaurant/store Mono County |
35,000 | 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.