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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
276–300 of 493Palmyra Waterworks
WI1280112 · 1,756 served
Mazomanie Waterworks
WI1130239 · 1,744 served
Whiting Waterworks
WI7500136 · 1,743 served
Osseo Waterworks
WI6620328 · 1,701 served
Marathon City Waterworks
WI7370151 · 1,695 served
Galesville Waterworks
WI6620271 · 1,679 served
Shorewood Hills Waterworks
WI1130236 · 1,670 served
Stratford Waterworks
WI7370168 · 1,643 served
Cambridge Water & Sewer Utility
WI1130074 · 1,638 served
Thorp Waterworks
WI6100337 · 1,636 served
Spring Green Waterworks
WI1570109 · 1,626 served
Fox Lake Waterworks
WI1140145 · 1,610 served
Random Lake Waterworks
WI4600355 · 1,594 served
Darien Waterworks
WI2650057 · 1,573 served
Elkhart Lake Waterworks
WI4600439 · 1,567 served
Niagara Waterworks
WI4380439 · 1,561 served
Federal Correctional Institution
WI7010105 · 1,550 served
Sharon Waterworks
WI2650145 · 1,549 served
Kettle Moraine Correctional Institution
WI4600449 · 1,544 served
Eagle River Waterworks
WI7640113 · 1,530 served
Brooklyn Waterworks
WI1230075 · 1,524 served
Cleveland Waterworks
WI4360426 · 1,524 served
Bangor Waterworks
WI6320233 · 1,520 served
Hurley Waterworks
WI8260116 · 1,515 served
Concordia University
WI2460118 · 1,500 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