Ventura County · tap water by city
FilteredWTR tracks 22 public water systems in Ventura County, and their own population counts add up to 836,685 people. None of them has a health-based violation on its EPA record from the last three years. In the latest round of lead testing, 19 systems reported a 90th-percentile result of zero. None came in at or above 0.0075 mg/L, which is half the federal action level of 0.015 mg/L.
The largest systems come first. Lead is each system's most recent 90th-percentile result from the federal Lead and Copper Rule, and the last column counts health-based violations from the last three years. Systems sample on their own schedules, so their monitoring periods end anywhere from 2023 to 2027.
| Water system | Cities served | People served | Latest lead (90th percentile) | Recent health violations |
|---|---|---|---|---|
| Oxnard Water Dept | Oxnard | 200,232 | Not detected, period ending 2027 | 0 |
| Ventura Water Department | Ventura | 112,285 | Not detected, period ending 2026 | 0 |
| Ventura WWD No. 8 - Simi Valley | Simi Valley | 94,736 | Not detected, period ending 2025 | 0 |
| Cal American Water Co | Not listed | 66,809 | 0.003 mg/L, period ending 2024 | 0 |
| City of Thousand Oaks Water Department | Thousand Oaks | 54,770 | Not detected, period ending 2025 | 0 |
| Camarillo Water Dept | Camarillo | 47,701 | Not detected, period ending 2025 | 0 |
| Golden State Water Company - Simi Valley | Not listed | 45,086 | 0.006 mg/L, period ending 2026 | 0 |
| Ventura CWWD No. 1 - Moorpark | Moorpark | 35,514 | Not detected, period ending 2024 | 0 |
| Camrosa Water District | Not listed | 32,700 | Not detected, period ending 2027 | 0 |
| City of Santa Paula | Santa Paula | 31,786 | Not detected, period ending 2025 | 0 |
| Port Hueneme City Water Dept | Port Hueneme | 21,582 | Not detected, period ending 2023 | 0 |
| California Water Service Co - Westlake | Not listed | 19,544 | 0.003 mg/L, period ending 2024 | 0 |
| Fillmore Water Dept | Fillmore | 16,419 | Not detected, period ending 2024 | 0 |
| Triunfo Water & Sanitation District | Not listed | 13,898 | Not detected, period ending 2025 | 0 |
| Casitas Municipal Water Dist | Not listed | 11,005 | Not detected, period ending 2023 | 0 |
| Ojai Water System | Ojai | 6,801 | Not detected, period ending 2023 | 0 |
| Ventura River Water District | Not listed | 6,100 | Not detected, period ending 2025 | 0 |
| Pleasant Valley Mutual Water Co | Not listed | 5,306 | Not detected, period ending 2024 | 0 |
| Channel Islands Beach CSD | Channel Islands Beach | 5,011 | Not detected, period ending 2025 | 0 |
| Meiners Oaks CWD | Meiners Oaks | 4,200 | Not detected, period ending 2026 | 0 |
| Naval Base Ventura County, Port Hueneme | Not listed | 3,500 | Not detected, period ending 2025 | 0 |
| Naval Base Ventura County, Point Mugu | Not listed | 1,700 | Not detected, period ending 2026 | 0 |
Each report covers the water system that serves that city, with its measured results and its full EPA compliance history.
Every system has to collect tap samples from a set list of homes and report the lead level at the 90th percentile. Nine out of ten sampled homes came in at or below that figure. The federal action level is 0.015 mg/L, and a system that goes over it has to take corrective steps and tell its customers. A zero means the samples came back below what the lab can detect.
A health-based violation means the system broke a rule tied to health, such as going over a contaminant limit or missing a required treatment step. Late paperwork and skipped reports go on the EPA record too, and this page leaves those out.
These figures describe the water each system sends out, and the water at your own faucet can test differently. Lead most often enters from a home's own pipes and fixtures, so houses built before 1986 are worth a closer look. Chlorine levels also drift with how far a street sits from the treatment plant.
A local FilteredWTR tech screens the water at your faucet for hardness, chlorine and sediment and explains each reading while you watch. The visit is free, and afterward the decision stays yours.
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