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 |
|---|---|---|---|---|
|
Indian Village County |
35 | 7 | 2 | |
|
R.s. Mutual Water Company Kern County |
35 | 3 | 0 | |
|
Sws Land Development INC Madera County |
35 | 4 | 0 | |
|
TN Truss Los Angeles County |
35 | 1 | 0 | |
|
Crew Wine Company Yolo County |
30 | 3 | 1 | |
|
Kyburz Mutual Water Company El Dorado County |
30 | 5 | 0 | |
|
Olivares Farms Water System Merced County |
28 | 1 | 0 | |
|
Mitchell's Avenue E Mobile Home Park Los Angeles County |
27 | 2 | 1 | |
|
Harmony Village Sutter County |
25 | 1 | 0 | |
|
Moreton Bay Professional Plaza Santa Barbara County |
25 | 6 | 1 | |
|
Santa Ynez Roblar Mobile Home Park Santa Barbara County |
25 | 4 | 0 | |
|
Silverfork School El Dorado County |
25 | 8 | 0 | |
|
Robinson's Corner MHP Butte County |
20 | 8 | 2 |
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.