Arsenic violations in California
113 active public water systems in California had a Arsenic violation in the past three years, 24 of them in the latest quarter of EPA's data. What Arsenic is and why it matters.
Systems with a Arsenic violation
Latest quarter first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
DD Mobile Home Park County |
275 | 9 | 3 | |
|
DI Giorgio School Water System Kern County |
268 | 3 | 0 | |
|
East Acres Mutual Water Company Madera County |
250 | 4 | 1 | |
|
Warner Unified School District San Diego County |
250 | 1 | 0 | |
|
Washoe Tribe Woodfords Woodfords · County |
250 | 2 | 1 | |
|
Cacheville Service Dist Yolo County |
239 | 8 | 1 | |
|
Moro RD WS #09 Monterey County |
210 | 1 | 0 | |
|
EL Adobe Poa, Inc. Kern County |
200 | 2 | 1 | |
|
MD 07 Marina View Heights Madera County |
200 | 1 | 0 | |
|
Sky Acres Mutual Water Corp Madera County |
175 | 2 | 1 | |
|
Lands of Promise Mwc Kern County |
174 | 2 | 1 | |
|
Mountain View Elementary School Stanislaus County |
170 | 2 | 1 | |
|
Oakley Mutual Water Company Contra Costa County |
170 | 2 | 1 | |
|
Melody Woods Water Company Santa Clara County |
168 | 3 | 0 | |
|
Psmcsd Vierra Estates WS Monterey County |
164 | 1 | 0 | |
|
Laguna Seca WC Monterey County |
162 | 1 | 0 | |
|
Mettler Valley Mutual Los Angeles County |
160 | 1 | 0 | |
|
Foster Road Mutual Water Company Santa Barbara County |
150 | 4 | 0 | |
|
Kinecta Fcu Santa Barbara County |
104 | 4 | 0 | |
|
Cemex Calif Cement LLC AV San Bernardino County |
100 | 1 | 0 | |
|
North Trails Mutual Water Company Los Angeles County |
100 | 3 | 1 | |
|
Round Valley Admin. Complex County |
100 | 6 | 1 | |
|
Rancho San Joaquin Mwc San Benito County |
96 | 3 | 1 | |
|
Bella Vista Water Sys Contra Costa County |
93 | 3 | 2 | |
|
Magnolia Mutual Water Sacramento County |
90 | 1 | 0 | |
|
Pit River Montgomery Creek Rancheria Montgomery Creek Rancheria · County |
90 | 11 | 0 | |
|
John Hovannisian Water System Madera County |
80 | 8 | 1 | |
|
Kern Mobile Estates LLC Kern County |
73 | 1 | 0 | |
|
The Village Mobile Home Park Los Angeles County |
71 | 2 | 1 | |
|
Keeler Community Service District Inyo County |
66 | 2 | 1 | |
|
Agriland Farming Madera County |
60 | 1 | 0 | |
|
Aguirre MHP County |
60 | 10 | 0 | |
|
Country Villa Apts Stanislaus County |
60 | 1 | 0 | |
|
Rancho Marina Sacramento County |
60 | 2 | 1 | |
|
Winterhaven Mobile Estates Los Angeles County |
56 | 2 | 0 | |
|
Rim Rock Water Company San Luis Obispo County |
55 | 2 | 0 | |
|
Angelique Maelee Properties County |
50 | 8 | 1 | |
|
Cobles Corner Stanislaus County |
50 | 1 | 0 | |
|
Lancaster Park Mobile Home Park Los Angeles County |
50 | 1 | 0 | |
|
Marquez Rental Madera County |
50 | 2 | 0 | |
|
Netto AG Inc. Kings County |
50 | 2 | 1 | |
|
Baker Commodities Inc. Kings County |
47 | 1 | 0 | |
|
Gold Rock Ranch Imperial County |
45 | 5 | 0 | |
|
Ironwood Camp San Bernardino County |
45 | 1 | 0 | |
|
Almira Water Association San Luis Obispo County |
40 | 2 | 0 | |
|
60th Street Assoc. Water System Kern County |
39 | 1 | 0 | |
|
Sandoval MHP County |
38 | 5 | 1 | |
|
Hungry Gulch Mwc Kern County |
36 | 1 | 0 | |
|
Cold Springs Subdivision Cold Springs Rancheria · County |
35 | 8 | 3 | |
|
First Mutual Water System Kern County |
35 | 1 | 0 |
About this data
A system is counted once if any of its violations in the past three years involved Arsenic, including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not Arsenic alone.
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.