Nitrate violations in California
524 active public water systems in California had a Nitrate violation in the past three years, 41 of them in the latest quarter of EPA's data. What Nitrate is and why it matters.
Systems with a Nitrate violation
Latest quarter first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Mayflower Park Riverside County |
94 | 1 | 0 | |
|
Acton Conservation Camp #11 Los Angeles County |
90 | 4 | 0 | |
|
Historic Priest Station, LLC Tuolumne County |
90 | 2 | 0 | |
|
Mettler County Water District Kern County |
90 | 2 | 1 | |
|
Pit River Montgomery Creek Rancheria Montgomery Creek Rancheria · County |
90 | 11 | 0 | |
|
Spring Canyon WA Monterey County |
90 | 2 | 1 | |
|
Stan's Yolo Marina Yolo County |
90 | 1 | 0 | |
|
Aerial Acres Water Company, Inc. Kern County |
87 | 2 | 1 | |
|
Tri Counties Club San Luis Obispo County |
87 | 2 | 0 | |
|
Bassi Ranch Mutual Water Co. San Luis Obispo County |
85 | 2 | 1 | |
|
Chamisal Mwc San Bernardino County |
84 | 3 | 1 | |
|
Ken Mar Gardens San Luis Obispo County |
84 | 2 | 0 | |
|
Round Valley Agency County |
84 | 7 | 1 | |
|
Valley Ford Water Association Sonoma County |
84 | 3 | 1 | |
|
Camp Maranatha Riverside County |
83 | 1 | 0 | |
|
Captain Cooper School WS Monterey County |
82 | 1 | 0 | |
|
Hidden Valley WA Monterey County |
81 | 3 | 2 | |
|
Questhaven Municipal Water District San Diego County |
81 | 2 | 0 | |
|
Crossover Community Church Fresno County |
80 | 2 | 0 | |
|
Green Mountain Water Company Santa Clara County |
80 | 1 | 0 | |
|
John Hovannisian Water System Madera County |
80 | 8 | 1 | |
|
Laguna Negra Mutual Water Co. San Luis Obispo County |
80 | 1 | 0 | |
|
Sans End RV Park County |
77 | 5 | 0 | |
|
Apple Ave WS #02 Monterey County |
75 | 2 | 1 | |
|
Cathedral Hills Mwc, INC Santa Cruz County |
75 | 2 | 0 | |
|
Duarte Nursery INC Water System Stanislaus County |
75 | 2 | 1 | |
|
Gas N Grab Tulare County |
75 | 1 | 0 | |
|
Olancha Mobil Mart Bishop · Inyo County |
75 | 2 | 0 | |
|
Pike Ranch Mutual Water CO Madera County |
74 | 4 | 1 | |
|
Wheel-Er in Family Wheel-er In Family Resort · County |
74 | 3 | 0 | |
|
Echo Peak Water Association El Dorado County |
73 | 1 | 0 | |
|
La Posta Upper County |
73 | 4 | 0 | |
|
All Saints Retreat and Formation Center San Diego County |
72 | 2 | 1 | |
|
Tahoe Sands Inn El Dorado County |
71 | 2 | 0 | |
|
Arviso Mobile Home Park County |
70 | 4 | 2 | |
|
Napa River Ranch Napa County |
70 | 5 | 3 | |
|
VFW Post 5551 San Bernardino County |
70 | 2 | 0 | |
|
Bakersfield National Cemetery WS Kern County |
69 | 1 | 0 | |
|
Rod McLellan Botanicals WS Monterey County |
69 | 1 | 0 | |
|
Pine Springs Ranch Riverside County |
68 | 1 | 0 | |
|
Holland Hulling Company Fresno County |
66 | 2 | 0 | |
|
Brookside MHP San Bernardino County |
65 | 7 | 3 | |
|
Camp Cedar Glen San Diego County |
65 | 1 | 0 | |
|
Cdf Pilot Rock Conservation Camp San Bernardino County |
65 | 1 | 0 | |
|
River RD WS #25 Monterey County |
65 | 2 | 1 | |
|
Elm Court Fresno County |
64 | 4 | 3 | |
|
Frazier Nut Farms, Inc. Stanislaus County |
64 | 1 | 0 | |
|
Silver Creek Madera County |
64 | 1 | 0 | |
|
Silver Creek Summer Home Tract Placer County |
64 | 1 | 0 | |
|
Twentynine Palms Inn San Bernardino County |
62 | 1 | 0 |
About this data
A system is counted once if any of its violations in the past three years involved Nitrate, including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not Nitrate 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.