California Water Quality
According to EPA Safe Drinking Water Information System (SDWIS), California has 3,068 active community water systems in this extract. PlainEnviro's health-based slice lists 17,705 violation records across 50 systems with at least one such row. These are historical EPA registry counts, not a statewide drinkability score.
Health-based violation records for 3,068 community water systems in California. Source: EPA Safe Drinking Water Information System (SDWIS).
Water Systems with Most Health-Based Records
| # | Water System | Health-Based Records | Health |
|---|---|---|---|
| 1 | CAL AM - OAKHURST Sacramento | 368 | Yes |
| 2 | CAL AM - RAYMOND Sacramento | 364 | Yes |
| 3 | CSA 70 W-4 PIONEERTOWN San Bernardino | 284 | Yes |
| 4 | Grindstone Rancheria Elk Creek | 234 | Yes |
| 5 | NORTH EDWARDS WD North Edwards | 203 | Yes |
| 6 | US ARMY FORT IRWIN Fort Irwin | 180 | Yes |
| 7 | PAPPAS & CO (MENDOTA) Fresno | 176 | Yes |
| 8 | DEL ORO RIVER ISLAND SERV TERR #1 Chico | 176 | Yes |
| 9 | LINDSAY, CITY OF Lindsay | 175 | Yes |
| 10 | HARRIS FARMS HEADQUARTERS Coalinga | 174 | Yes |
| 11 | COLUSA CO. WWD #1 - GRIMES Grimes | 136 | Yes |
| 12 | IRONWOOD CAMP Newberry Springs | 136 | Yes |
| 13 | ARVIN COMMUNITY SERVICES DIST Arvin | 133 | Yes |
| 14 | KNOLL ENTERPRISES Ludlow | 125 | Yes |
| 15 | LANARE COMMUNITY SERVICES DIST Riverdale | 120 | Yes |
| 16 | CARUTHERS COMM SERV DIST Caruthers | 120 | Yes |
| 17 | KETTLEMAN CITY CSD Kettleman City | 120 | Yes |
| 18 | LEMOORE, CITY OF Lemoore | 119 | Yes |
| 19 | NPS-WOLVERTON Three Rivers | 119 | Yes |
| 20 | LAND PROJECTS MUTUAL WATER CO. Lancaster | 118 | Yes |
| 21 | BAR-LEN MWC Barstow | 117 | Yes |
| 22 | PAUMA VALLEY WATER COMPANY Pauma Valley | 113 | Yes |
| 23 | KEYES COMMUNITY SERVICES DIST. Keyes | 110 | Yes |
| 24 | FOREST SPRINGS Boulder Creek | 109 | Yes |
| 25 | VALLEY FORD WATER ASSOCIATION Valley Ford | 109 | Yes |
| 26 | HARRIS FEEDING COMPANY Coalinga | 108 | Yes |
| 27 | LAS CUMBRES MUTUAL WATER CO Los Gatos | 107 | Yes |
| 28 | SIERRA LINDA MUTUAL WATER CO North Fork | 106 | Yes |
| 29 | RIVERDALE PUBLIC UTILITY DISTRICT Riverdale | 104 | Yes |
| 30 | MADERA CO MD1-HIDDEN LAKE ESTATES Madera | 102 | Yes |
| 31 | QUIET OAKS MOBILE HOME PARK Stockton | 102 | Yes |
| 32 | MAHER MUTUAL WATER COMPANY Bakersfield | 98 | Yes |
| 33 | RAINBIRD VALLEY MWC Weldon | 96 | Yes |
| 34 | ALPAUGH COMMUNITY SERVICES DISTRICT Alpaugh | 96 | Yes |
| 35 | BRIDGEPORT PUD Bridgeport | 93 | Yes |
| 36 | R.S. MUTUAL WATER COMPANY Wofford Heights | 91 | Yes |
| 37 | LSID - TONYVILLE Lindsay | 91 | Yes |
| 38 | MCKEE BRIDGE MOBILE HOME PARK Encinitas | 91 | Yes |
| 39 | MD 42 STILL MEADOW Madera | 88 | Yes |
| 40 | CSA 70 W-3 HACIENDA San Bernardino | 88 | Yes |
| 41 | SURFWOOD MUTUAL WATER CORPORATION Mendocino | 87 | Yes |
| 42 | CSA 70-F MORONGO San Bernardino | 87 | Yes |
| 43 | INDIAN OAKS TRAILER PARK Murrieta | 86 | Yes |
| 44 | ENCINAL RD WS #01 Salinas | 84 | Yes |
| 45 | SIERRA VISTA ASSOCIATION Clovis | 84 | Yes |
| 46 | UC DESERT RESEARCH AND EXTENSION CENTER Holtville | 83 | Yes |
| 47 | SONOMA COUNTY MUTUAL WATER COMPANY San Francisco | 83 | Yes |
| 48 | HARRIS FARMS SOUTH 101-144 Coalinga | 82 | Yes |
| 49 | BORON CSD Boron | 80 | Yes |
| 50 | KERN MOBILE ESTATES LLC Los Angeles | 79 | Yes |
Most Common Contaminants in California
| Contaminant | Violations | Systems Affected |
|---|---|---|
| Arsenic | 5,537 | 146 |
| Nitrate | 2,428 | 137 |
| TTHM | 2,031 | 121 |
| Combined Uranium | 1,646 | 53 |
| Surface Water Treatment Rule | 1,265 | 164 |
| Total Haloacetic Acids (HAA5) | 1,208 | 92 |
| Coliform (TCR) | 882 | 235 |
| LEAD AND COPPER RULE REVISIONS | 509 | 505 |
| Fluoride | 414 | 16 |
| Groundwater Rule | 386 | 57 |
| Revised Total Coliform Rule | 303 | 117 |
| Gross Alpha Particle Activity | 151 | 16 |
| Interim Enhanced Surface Water Treatment Rule | 132 | 30 |
| Selenium | 107 | 9 |
| CARBON, TOTAL | 77 | 10 |
Cities with Water Quality Issues
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About This Data
Water quality data is from the EPA Safe Drinking Water Information System (SDWIS). Health-based violations include Maximum Contaminant Level (MCL) and Treatment Technique (TT) violations. Only community water systems (CWS) in California are included.
Source: U.S. Environmental Protection Agency, SDWIS Federal Reporting Services U.S. Environmental Protection Agency, SDWIS Federal Reporting Services
Read our methodology - how this data is sourced, computed, and verified.