St. Clair County tap water
0 of 12 water systems serving St. Clair County with full PFAS testing averaged above a 2024 federal PFAS level at one or more sampling points.
- 21 community water systems list this county as served; 11 serve 3,300+ people with full PFAS testing.
- 2 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 |
|---|---|---|---|---|
| Port Huron, City of | Surface water | 28,983 | No | 0 |
| Port Huron Township | Purchased surface water | 10,654 | No | 0 |
| Fort Gratiot Township | Purchased surface water | 10,640 | No | 0 |
| Marysville, City of | Surface water | 9,959 | No | 0 |
| Clay Township | Purchased surface water | 9,866 | No | 0 |
| Ira Township | Surface water | 6,510 | No | 0 |
| St. Clair Water and Sewer Authority | Surface water | 5,847 | No | 0 |
| St. Clair, City of | Surface water | 5,464 | No | 1 |
| Kimball Township | Purchased surface water | 5,170 | No | 1 |
| Marine City | Surface water | 4,652 | No | 0 |
| Algonac, City of | Surface water | 4,110 | 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.