Surface Water Treatment Rule (SWTR) violations in California
56 active public water systems in California had a Surface Water Treatment Rule (SWTR) violation in the past three years, 28 of them in the latest quarter of EPA's data. What Surface Water Treatment Rule (SWTR) is and why it matters.
Systems with a Surface Water Treatment Rule (SWTR) violation
Latest quarter first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Tule River Reservation Main Tule River Reservation · County |
2,560 | 9 | 2 | |
|
Orleans C.s.d. Humboldt County |
636 | 4 | 3 | |
|
Cazadero Water Company, Inc. (puc) Sonoma County |
525 | 3 | 2 | |
|
Plaskett Creek Campgrounds WS Monterey County |
501 | 2 | 1 | |
|
Potter Valley School District Mendocino County |
309 | 1 | 1 | |
|
Grindstone Rancheria County |
150 | 9 | 4 | |
|
Rio Bend RV Golf Resort & Storm Crossing Imperial County |
130 | 3 | 2 | |
|
Salyer Heights W.s., INC Trinity County |
130 | 1 | 1 | |
|
Luna Trattoria Mendocino County |
120 | 1 | 1 | |
|
Yurok Weitchpec County |
120 | 5 | 0 | |
|
Burnt Ranch Estates Trinity County |
115 | 2 | 2 | |
|
Floriston Water System Nevada County |
110 | 3 | 1 | |
|
Yurok Wautec County |
96 | 5 | 0 | |
|
Dhs Border Patrol Hwy 94 Checkpoint San Diego County |
83 | 2 | 1 | |
|
Mescal Creek Water, INC Los Angeles County |
80 | 2 | 2 | |
|
Yurok Kepel County |
76 | 7 | 1 | |
|
Sonoma County Parks-Stillwater Cove Sonoma County |
70 | 1 | 1 | |
|
Pigeon Point Hostel San Mateo County |
67 | 1 | 1 | |
|
Six Acres Water Company Sonoma County |
66 | 2 | 1 | |
|
Laurel Community League Santa Cruz County |
64 | 2 | 1 | |
|
Palomino Estates Water Company Humboldt County |
64 | 4 | 3 | |
|
Rock Creek Mutual Water Co. Del Norte County |
60 | 1 | 1 | |
|
Dhs Border Patrol I-8 Checkpoint San Diego County |
50 | 2 | 1 | |
|
Branscomb Mobile Home Park Mendocino County |
42 | 3 | 2 | |
|
Redwood Heights Mutual Water Company Sonoma County |
30 | 1 | 1 | |
|
Yurok McCoy Kenek County |
30 | 6 | 0 | |
|
Lockheed Martin Space Systems Santa Cruz County |
28 | 4 | 1 | |
|
Puente Housing Solutions San Mateo County |
28 | 1 | 1 | |
|
Montecito Water Dist Santa Barbara County |
12,010 | 1 | 0 | |
|
Signal Hill City, Water Dept. Signal Hill · Los Angeles County |
11,848 | 3 | 0 | |
|
Casitas Municipal Water Dist Ventura County |
11,005 | 2 | 0 | |
|
Huron, City of Huron · Fresno County |
7,306 | 1 | 0 | |
|
Weaverville C.s.d. Trinity County |
3,975 | 1 | 0 | |
|
San Antonio Lake Park South WS Monterey County |
653 | 1 | 0 | |
|
San Simeon Csd San Luis Obispo County |
462 | 1 | 0 | |
|
Del Oro Water Company Strawberry Div. Tuolumne County |
386 | 1 | 0 | |
|
Berkeley Tuolumne Camp Tuolumne County |
380 | 1 | 0 | |
|
Havasu Water Company County |
361 | 11 | 4 | |
|
Woodside RV Park Mendocino County |
280 | 2 | 0 | |
|
Paskenta Comm. Services Dist. Tehama County |
237 | 1 | 0 | |
|
Howonquet Community(smith River) Howonquet Community · County |
220 | 5 | 0 | |
|
Usn San Clemente Island San Diego County |
200 | 3 | 0 | |
|
Kashia County |
153 | 7 | 0 | |
|
Elkins Ranch Ventura County |
150 | 2 | 1 | |
|
Cody Water Association El Dorado County |
148 | 1 | 0 | |
|
Magnolia Union School Imperial County |
142 | 2 | 0 | |
|
Madera CO SA16 Sumner Hill Madera County |
135 | 2 | 0 | |
|
Empire Landing Campground-Sundance RV San Bernardino County |
126 | 2 | 0 | |
|
Cold Spring Tavern Santa Barbara County |
120 | 2 | 0 | |
|
Mulberry Union School Imperial County |
85 | 2 | 0 |
About this data
A system is counted once if any of its violations in the past three years involved Surface Water Treatment Rule (SWTR), including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not Surface Water Treatment Rule (SWTR) 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.