E. coli (Escherichia coli) violations in California
20 active public water systems in California had a E. coli (Escherichia coli) violation in the past three years, 21 of them in the latest quarter of EPA's data. What E. coli (Escherichia coli) is and why it matters.
Systems with a E. coli (Escherichia coli) violation
Latest quarter first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Santa Clara Valley Medical Center Santa Clara County |
3,000 | 3 | 2 | |
|
Pinnacles National Park-East District San Benito County |
1,811 | 1 | 1 | |
|
Cal Trans Division Creek Inyo County |
300 | 1 | 1 | |
|
Mitomkai Tribal Water System Lockhart · County |
300 | 3 | 1 | |
|
Utu Utu Gwaitu Paiute Tribe Benton Paiute Reservation · County |
222 | 4 | 3 | |
|
Three Rivers Hideaway Tulare County |
135 | 2 | 1 | |
|
Fort Independence Fort Independence Reservation · County |
120 | 5 | 3 | |
|
Round Valley Health Clinic County |
119 | 7 | 3 | |
|
Villa Robles Water System San Benito County |
98 | 3 | 2 | |
|
Vineyard Estates Mwc San Benito County |
90 | 2 | 1 | |
|
Arviso Mobile Home Park County |
70 | 4 | 2 | |
|
Polymerpak Tulare County |
50 | 1 | 1 | |
|
Hoot Owl Creek/alex. Valley Vineyards JV Sonoma County |
46 | 1 | 0 | |
|
Sandoval MHP County |
38 | 5 | 1 | |
|
La Cienega MHP County |
30 | 2 | 1 | |
|
Coyote Valley Sporting Clays Santa Clara County |
27 | 1 | 1 | |
|
Karah Estate Winery Sonoma County |
27 | 1 | 1 | |
|
Alma Latter-Day Saints Church Santa Clara County |
25 | 2 | 1 | |
|
Mora MHP County |
25 | 2 | 1 | |
|
Oroville Mobile Home Park Butte County |
76 | 2 | 0 |
About this data
A system is counted once if any of its violations in the past three years involved E. coli (Escherichia coli), including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not E. coli (Escherichia coli) 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.