Merced County tap water
4 of 11 water systems serving Merced County with full PFAS testing averaged above a 2024 federal PFAS level at one or more sampling points.
- 22 community water systems list this county as served; 11 serve 3,300+ people with full PFAS testing.
- 13 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 |
|---|---|---|---|---|
| City of Merced | Groundwater | 96,073 | Yes | 0 |
| City of Los Banos | Groundwater | 48,896 | No | 1 |
| City of Atwater | Groundwater | 29,479 | Yes | 0 |
| City of Livingston | Groundwater | 14,894 | No | 1 |
| Winton Water & Sanitary Dist | Groundwater | 9,745 | No | 1 |
| Delhi Cwd | Groundwater | 7,784 | No | 0 |
| City of Dos Palos | Surface water | 7,452 | No | 11 |
| City of Gustine | Groundwater | 6,138 | No | 1 |
| Cal Am - Meadowbrook | Groundwater | 5,723 | Yes | 0 |
| Hilmar County Water District | Groundwater | 5,504 | No | 14 |
| Planada Csd | Groundwater | 4,164 | Yes | 1 |
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.