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 |
|---|---|---|---|---|
|
McFarland, City of Mcfarland · Kern County |
14,161 | 3 | 1 | |
|
Kingsburg, City of Kingsburg · Fresno County |
13,540 | 1 | 0 | |
|
City of Newman-Water Department Newman · Stanislaus County |
12,389 | 1 | 0 | |
|
Anza Valley Business Riverside County |
10,014 | 1 | 0 | |
|
Pismo Beach Water Department San Luis Obispo County |
7,944 | 2 | 0 | |
|
Cutler Pud Tulare County |
6,200 | 2 | 1 | |
|
Hilmar County Water District Merced County |
5,504 | 1 | 0 | |
|
Pleasant Valley Mutual Water CO Ventura County |
5,306 | 1 | 0 | |
|
Needles, City of Needles · San Bernardino County |
4,872 | 1 | 0 | |
|
Farm Mutual W.c. (the) Riverside County |
4,026 | 1 | 0 | |
|
Sheep Creek Water Company San Bernardino County |
4,002 | 1 | 0 | |
|
Idyllwild Water District Riverside County |
3,762 | 2 | 0 | |
|
Big River Development Big River · County |
3,550 | 9 | 4 | |
|
Marygold Mwc San Bernardino County |
3,155 | 1 | 0 | |
|
Littlerock Creek Irrigation Dist. Los Angeles County |
3,066 | 1 | 0 | |
|
Santa Clara Valley Medical Center Santa Clara County |
3,000 | 3 | 2 | |
|
Bishop Paiute-Shoshone Tribe Bishop Paiute-shoshone Reservation · County |
2,735 | 3 | 1 | |
|
Tuolumne Black Oak Casino County |
2,600 | 2 | 0 | |
|
Selma High School Fresno County |
2,225 | 2 | 1 | |
|
Cal Trans C.v. Kane San Bernardino County |
2,200 | 1 | 0 | |
|
Chemehuevi Water County |
2,200 | 4 | 0 | |
|
Diamond Valley Market Water Riverside County |
2,195 | 1 | 0 | |
|
Buttonwillow Tiger Mart Kern County |
2,006 | 1 | 0 | |
|
Marysville Raceway Park Yuba County |
2,000 | 1 | 0 | |
|
Sierra Tahoe Main Lodge El Dorado County |
1,900 | 5 | 0 | |
|
Sierra Tahoe West Bowl El Dorado County |
1,900 | 2 | 0 | |
|
Woodville Public Utility Dist Tulare County |
1,740 | 1 | 0 | |
|
Lake Don Pedro Csd Tuolumne County |
1,700 | 3 | 1 | |
|
Richgrove Community Services District Tulare County |
1,617 | 8 | 3 | |
|
Durham Irrigation District Butte County |
1,581 | 1 | 0 | |
|
Bear River/singley Hill County |
1,530 | 4 | 0 | |
|
Nojoqui Falls County Park Santa Barbara County |
1,502 | 1 | 0 | |
|
Rusack Vineyards Santa Barbara County |
1,327 | 1 | 0 | |
|
Del Oro River Island Serv Terr #1 Tulare County |
1,277 | 2 | 0 | |
|
Rio Bravo Greeley School Water System Kern County |
1,219 | 1 | 0 | |
|
Grimmway Enterprises-Malaga Water System Kern County |
1,200 | 2 | 0 | |
|
Atascadero State Hospital San Luis Obispo County |
1,100 | 1 | 0 | |
|
San Joaquin County-Raymus Village San Joaquin County |
1,086 | 1 | 0 | |
|
Thunderbird Cwd San Bernardino County |
1,056 | 2 | 0 | |
|
LA Purisima Golf Course Santa Barbara County |
1,024 | 1 | 0 | |
|
San Antonio Lake Park North WS Monterey County |
1,002 | 1 | 0 | |
|
Baker Community Services District San Bernardino County |
1,000 | 3 | 1 | |
|
Henningsen Lotus Park Water System El Dorado County |
1,000 | 2 | 0 | |
|
Nugget Campground El Dorado County |
1,000 | 1 | 0 | |
|
Montana de Oro State Park San Luis Obispo County |
990 | 1 | 0 | |
|
Nyeland Acres Mutual Water CO Ventura County |
975 | 2 | 0 | |
|
Lakeside School Kern County |
897 | 2 | 1 | |
|
Oasis Date Gardens Riverside County |
832 | 2 | 1 | |
|
1000 Trails / Soledad Canyon Preserve Los Angeles County |
812 | 1 | 0 | |
|
Senior Canyon Mutual Water CO Ventura County |
800 | 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.