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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
101–125 of 493Rice Lake Waterworks
WI6030138 · 9,012 served
Plymouth Utilities
WI4600446 · 8,964 served
Sheboygan Falls Utilities
WI4600455 · 8,687 served
Pewaukee City Water and Sewer Utility
WI2680214 · 8,671 served
Monona Waterworks
WI1130245 · 8,624 served
Delavan Waterworks
WI2650113 · 8,451 served
Rhinelander Water & Wastewater
WI7440126 · 8,234 served
Mukwonago Waterworks
WI2680209 · 8,190 served
Pewaukee Village Waterworks
WI2680229 · 8,166 served
Muskego Water Utility
WI2681741 · 8,150 served
Waupun Utilities
WI1140131 · 8,056 served
Ashland Water Utility
WI8020373 · 8,000 served
Jefferson Waterworks
WI1280104 · 7,926 served
Jackson Waterworks
WI2670111 · 7,844 served
Antigo Waterworks
WI7340086 · 7,780 served
Mt Horeb Waterworks
WI1130247 · 7,756 served
Ripon Water Utility
WI4200476 · 7,716 served
Kimberly Waterworks
WI4450342 · 7,608 served
Ledgeview Tn Sanitary Dist 2
WI4051418 · 7,602 served
New London Waterworks
WI4690398 · 7,187 served
Lake Geneva Utility Commission
WI2650066 · 7,107 served
Kronenwetter Water & Sewer Utility
WI7371700 · 6,931 served
Fox Point Waterworks
WI2410584 · 6,808 served
Village of Lake Hallie Waterworks
WI6090849 · 6,701 served
Town of Brookfield San Dist 4
WI2680239 · 6,419 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