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Wisconsin Water Quality
493
Utilities in database
4.1M
Residents served
38%
On private wells
3
Key contaminants tracked
Drinking Water in Wisconsin
Wisconsin has 493 community water systems serving approximately 4.1 million residents. Primary water sources include groundwater. The most commonly reported contaminants include arsenic, lead, disinfection byproducts. 38% of Wisconsin residents rely on private wells. DNR holds primary enforcement authority under the Safe Drinking Water Act.
Utilities in Wisconsin
251–275 of 493Redgranite Waterworks
WI4700269 · 2,019 served
Crandon Waterworks
WI7210107 · 1,958 served
Harmony Grove San Dist
WI1110101 · 1,950 served
Eagle Waterworks
WI2680198 · 1,950 served
Chetek Waterworks
WI6030129 · 1,931 served
Somers Water Utility
WI2301421 · 1,930 served
Trempealeau Waterworks
WI6620332 · 1,888 served
Hammond Waterworks
WI6560121 · 1,884 served
Scott Water Utility Dist
WI4050071 · 1,875 served
Roberts Waterworks
WI6560134 · 1,872 served
Durand Waterworks
WI6470107 · 1,868 served
Port Edwards Water Utility
WI7720113 · 1,866 served
Weyauwega Waterworks
WI4690403 · 1,856 served
Fox Lake Correctional Institution
WI1140144 · 1,850 served
Spencer Waterworks
WI7370108 · 1,848 served
Adams Waterworks
WI7010107 · 1,847 served
Fontana Water Utility
WI2650128 · 1,839 served
Colby Waterworks
WI7370169 · 1,829 served
Campbellsport Waterworks
WI4200461 · 1,825 served
Whitehall Waterworks
WI6620275 · 1,820 served
Wind Point Water Dept
WI2520191 · 1,804 served
Randolph Water Dept
WI1110125 · 1,800 served
Menomonee Falls Ww - Groundwater
WI2685747 · 1,796 served
Fall River Waterworks
WI1110098 · 1,793 served
Cameron Waterworks
WI6030127 · 1,787 served
Key Contaminant Concerns in Wisconsin
Lead
Lead is a naturally occurring heavy metal that was widely used in plumbing infrastructure until it was banned for new installations in 1986. An estimated 9.2 million lead service lines still connect homes to public water mains across the United States, along with millions of homes with lead solder in their internal plumbing.
DBPs
When utilities add chlorine to water to kill pathogens, it reacts with dissolved organic matter — leaves, algae, soil — to produce disinfection byproducts (DBPs). Over 600 DBPs have been identified. The EPA regulates two groups: total trihalomethanes (TTHMs, including chloroform) and haloacetic acids (HAA5). DBP levels tend to be highest in surface water systems and in warm months when organic matter is elevated.
Arsenic
Arsenic (As) occurs naturally in rock and soil, dissolving into groundwater through natural weathering processes. Inorganic arsenic — the form found in drinking water — is a known human carcinogen. The western United States has particularly arsenic-rich geological formations, but elevated levels have been found in 48 states. Arsenic is tasteless and odorless.
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Data source: Utility data from EPA SDWIS. 493 active community water systems ingested. CCR contaminant data ingestion in progress.
Last updated: 2026-04-19