Sonoma County tap water
2 of 16 water systems serving Sonoma County with full PFAS testing averaged above a 2024 federal PFAS level at one or more sampling points.
- 128 community water systems list this county as served; 13 serve 3,300+ people with full PFAS testing.
- 20 had a health-based violation since 2021-10-26.
Largest systems serving this county
| System | Source | People served (whole system) | PFAS above a 2024 level? | Violations since 2021-10-26 |
|---|---|---|---|---|
| Santa Rosa, City of | Groundwater | 178,452 | No | 0 |
| Petaluma, City of | Groundwater | 61,427 | No | 0 |
| Rohnert Park, City of | Groundwater | 43,821 | No | 0 |
| Windsor, Town of | Groundwater | 25,561 | No | 0 |
| Valley of the Moon Water District | Groundwater | 23,140 | Yes | 0 |
| Healdsburg, City of | Groundwater under surface influence | 10,972 | No | 0 |
| Sonoma, City of | Groundwater | 10,619 | Yes | 0 |
| Cloverdale, City of | Groundwater under surface influence | 8,710 | No | 0 |
| California-American Larkfield (Puc) | Groundwater | 7,911 | No | 0 |
| Sebastopol, City of | Groundwater | 7,522 | No | 0 |
| Cotati, City of | Groundwater | 7,290 | No | 0 |
| Sweetwater Springs Cwd - Guerneville | Groundwater | 5,156 | No | 0 |
Which one is yours? A county usually has several utilities. Your bill or your utility's annual water-quality report names yours. Population is for the whole system, which can cross county lines.
Not medical or legal advice. UCMR 5 results are screening data, not compliance determinations.
Sources and freshness
Public-water-system facts, violations and lead/copper results: EPA ECHO SDWA download (SDWIS snapshot 2026-10-13). PFAS and lithium results: EPA UCMR 5 final data (sampling 2023–2025). Both are U.S. government works, downloaded 2026-10-26. Numbers are computed by the published method; the same fields are in the open data files.