Wisconsin drinking water quality
Wisconsin has 11,026 active public water systems serving 5.2 million people. 1,985 of them, 18%, had at least one EPA violation in the past three years, 768 have an unresolved violation today, and 23 are designated serious violators by the EPA.
Active systems
11,026
in 71 counties
People served
5.2M
1,051 community systems serve 4.3M
Violations, past 3 years
1,985
18% of active systems
Serious violators
23
49 systems carry a health flag
Largest counties
All 71 countiesLargest community water systems
All 11,026 systems| System | Serves | Status |
|---|---|---|
| Milwaukee Waterworks Milwaukee County |
626,000 | |
| Madison Water Utility Dane County |
272,000 | |
| Green Bay Waterworks Brown County |
107,369 | |
| Racine Waterworks Racine County |
105,100 | |
| Kenosha Water Utility Kenosha County |
99,218 | |
| Appleton Waterworks Outagamie County |
74,511 | |
| Waukesha Water Utility Waukesha County |
70,718 | |
| Eau Claire Waterworks Eau Claire County |
70,587 | |
| Janesville Water Utility Rock County |
64,415 | |
| West Allis Waterworks Milwaukee County |
63,240 |
About the Wisconsin data
Retrieved from EPA ECHO on Oct 11, 2026.