All water systems in California
7,380 systems
| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Nevada ID Loma Rica Nevada County |
14,072 | 0 | 0 | |
|
Cwsc King City San Jose · Monterey County |
14,046 | 0 | 0 | |
|
Tract 180 Mutual Water Co. Los Angeles County |
14,000 | 1 | 0 | |
|
Chowchilla City Water Dept Chowchilla · Madera County |
13,916 | 0 | 0 | |
|
Triunfo Water & Sanitation District Ventura County |
13,898 | 0 | 0 | |
|
Nipomo Comm Services Dist San Luis Obispo County |
13,771 | 0 | 0 | |
|
Avenal, City of Avenal · Kings County |
13,696 | 1 | 1 | |
|
Trabuco Canyon Water District Orange County |
13,659 | 0 | 0 | |
|
Kingsburg, City of Kingsburg · Fresno County |
13,540 | 1 | 0 | |
|
Westborough Water District San Mateo County |
13,486 | 0 | 0 | |
|
Tud Upper Basin Water System Tuolumne County |
13,331 | 1 | 0 | |
|
UC Davis Yolo County |
13,177 | 1 | 0 | |
|
Muscoy Mwc No. 1 San Bernardino County |
13,000 | 1 | 0 | |
|
Sbdno County Service Area 70j San Bernardino County |
12,895 | 0 | 0 | |
|
Cal-Water Service Co.-Marysville Yuba County |
12,888 | 0 | 0 | |
|
Yocha Dehe Potable Water System County |
12,800 | 2 | 0 | |
|
Big Bear City Csd Big Bear City · San Bernardino County |
12,738 | 0 | 0 | |
|
City of Grover Beach Public Works Dept San Luis Obispo County |
12,701 | 0 | 0 | |
|
Lindsay, City of Lindsay · Tulare County |
12,659 | 1 | 0 | |
|
Mendota, City of Mendota · Fresno County |
12,595 | 0 | 0 | |
|
Los Angeles Cwwd 40, Reg. 38-Lake la Los Angeles County |
12,582 | 0 | 0 | |
|
City of Dixon Solano County |
12,540 | 0 | 0 | |
|
City of Newman-Water Department Newman · Stanislaus County |
12,389 | 1 | 0 | |
|
Sycuan County |
12,350 | 0 | 0 | |
|
Thermalito Water & Sewer Dist Butte County |
12,209 | 0 | 0 | |
|
Fortuna, City of Fortuna · Humboldt County |
12,133 | 0 | 0 | |
|
Montecito Water Dist Santa Barbara County |
12,010 | 1 | 0 | |
|
Cabrillo College Santa Cruz County |
12,000 | 0 | 0 | |
|
Lupine Bass Lake Madera County |
11,930 | 0 | 0 | |
|
Tuttle Creek Campground Inyo County |
11,908 | 0 | 0 | |
|
Signal Hill City, Water Dept. Signal Hill · Los Angeles County |
11,848 | 3 | 0 | |
|
Town of Hillsborough San Mateo County |
11,766 | 0 | 0 | |
|
Crestline Village Cwd Division 10 San Bernardino County |
11,650 | 0 | 0 | |
|
Los Angeles Cwwd 40, R 24,27,33-Pearblsm Los Angeles County |
11,609 | 0 | 0 | |
|
Greenfield County WD Kern County |
11,590 | 0 | 0 | |
|
Camp Pendleton (north) San Diego County |
11,576 | 0 | 0 | |
|
Ccwd Ebbetts Pass Calaveras County |
11,545 | 0 | 0 | |
|
City of Bell Gardens Bell Gardens · Los Angeles County |
11,413 | 0 | 0 | |
|
Plumas Lake Yuba County |
11,374 | 0 | 0 | |
|
City of Anderson Anderson · Shasta County |
11,323 | 1 | 1 | |
|
Red Hawk Casino Shingle Springs Shingle Springs · County |
11,268 | 2 | 1 | |
|
City of Rio Vista Rio Vista · Solano County |
11,206 | 1 | 1 | |
|
Scotts Valley Water District Santa Cruz County |
11,197 | 0 | 0 | |
|
Exeter, City of Exeter · Tulare County |
11,169 | 1 | 0 | |
|
Tud Sonora/jamestown Water System Tuolumne County |
11,113 | 1 | 0 | |
|
Cal-Water Service Co.-Oroville Butte County |
11,047 | 0 | 0 | |
|
Casitas Municipal Water Dist Ventura County |
11,005 | 2 | 0 | |
|
Sierra Madre-City, Water Dept. Sierra Madre · Los Angeles County |
11,000 | 0 | 0 | |
|
Healdsburg, City of Healdsburg · Sonoma County |
10,972 | 0 | 0 | |
|
Gswc Willowbrook Los Angeles County |
10,793 | 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.