Wisconsin tap water
18 of 192 Wisconsin water systems with full PFAS testing (9%) averaged above a 2024 federal PFAS level at one or more sampling points.
- 1,022 active community water systems in the EPA file; 178 serve 3,300+ people and have a full PFAS set.
- 304 systems had at least one health-based violation since 2021-10-26.
- 5 systems report a lead 90th percentile above 15 ppb (some results are old; check each system page).
Largest systems
| System | People served | PFAS above a 2024 level? | Health-based violations since 2021-10-26 |
|---|---|---|---|
| Milwaukee Waterworks | 626,000 | No | 0 |
| Madison Water Utility | 272,000 | No | 1 |
| Green Bay Waterworks | 107,369 | No | 0 |
| Racine Waterworks | 105,100 | No | 0 |
| Kenosha Water Utility | 99,218 | No | 0 |
| Appleton Waterworks | 74,511 | No | 0 |
| Waukesha Water Utility | 70,718 | No | 36 |
| Eau Claire Waterworks | 70,587 | No | 0 |
Counties
Dane County15 systems with full PFAS testingMilwaukee County14 systems with full PFAS testingWaukesha County12 systems with full PFAS testing
All 15 utilities with a page in Wisconsin
- Appleton Waterworks 74,511
- Eau Claire Waterworks 70,587
- Fond Du Lac Waterworks 44,678
- Green Bay Waterworks 107,369
- Janesville Water Utility 64,415
- Kenosha Water Utility 99,218
- LA Crosse Waterworks 53,000
- Madison Water Utility 272,000
- Milwaukee Waterworks 626,000
- Oshkosh Waterworks 63,000
- Racine Waterworks 105,100
- Sheboygan Water Utilities 49,931
- Waukesha Water Utility 70,718
- Wauwatosa Waterworks 49,064
- West Allis Waterworks 63,240
Why not "the state's water quality"? You drink from one utility, not a state. Rollups count systems, not people, so one large utility counts the same as a small one. Use the system pages for your actual water.
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.