State Hub
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
126–150 of 493Rib Mountain Water Utility
WI7370660 · 6,398 served
Lake Mills Waterworks
WI1280108 · 6,211 served
Waupaca Waterworks
WI4690402 · 6,062 served
Prairie Du Chien Waterworks
WI6120250 · 6,005 served
Evansville Waterworks
WI1540047 · 5,703 served
Slinger Water Utility
WI2670116 · 5,659 served
Milton Waterworks
WI1540130 · 5,588 served
Berlin Waterworks
WI4240216 · 5,524 served
Edgerton Waterworks
WI1540119 · 5,512 served
Harrison Utilities - Fka Waverly Sd
WI4080076 · 5,500 served
North Fond Du Lac Waterworks
WI4200405 · 5,414 served
Lawrence Waterworks
WI4051625 · 5,398 served
Waterford Waterworks
WI2520202 · 5,368 served
Columbus Utilities
WI1110038 · 5,173 served
Mayville Waterworks
WI1140057 · 5,112 served
Richland Center Waterworks
WI1530068 · 5,100 served
East Troy Waterworks
WI2650123 · 5,054 served
West Salem Waterworks
WI6320334 · 5,045 served
Shawano Lk San Dist 1
WI4590457 · 4,950 served
Union Grove Waterworks
WI2520200 · 4,900 served
Suamico Waterworks
WI4051031 · 4,697 served
Clintonville Utilities
WI4690391 · 4,635 served
Oconto Waterworks
WI4430495 · 4,610 served
Windsor Water Utility South
WI1130267 · 4,607 served
Sheboygan Tn Waterworks
WI4600403 · 4,596 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