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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
151–175 of 493Dodgeville Waterworks
WI1250079 · 4,583 served
Mauston Waterworks
WI7290129 · 4,456 served
Baldwin Waterworks
WI6560119 · 4,440 served
Viroqua Waterworks
WI6630263 · 4,362 served
Medford Waterworks
WI8610125 · 4,318 served
Kewaskum Waterworks
WI2670112 · 4,309 served
Saukville Waterworks
WI2460134 · 4,268 served
Prescott Waterworks
WI6480243 · 4,258 served
Chilton Waterworks
WI4080222 · 4,191 served
Cross Plains Waterworks
WI1130219 · 4,100 served
Village of Bloomfield
WI2651469 · 4,071 served
Pulaski Waterworks
WI4050355 · 4,040 served
Prairie Du Sac Waterworks
WI1570100 · 4,006 served
Algoma Tn Sanitary Dist 1
WI4711611 · 3,935 served
Kiel Waterworks
WI4360427 · 3,932 served
Lancaster Waterworks
WI1220107 · 3,907 served
Marshall Waterworks
WI1130237 · 3,862 served
Wrightstown Waterworks
WI4050464 · 3,815 served
Arcadia Waterworks
WI6620319 · 3,737 served
Waupun Correctional Inst
WI1140142 · 3,706 served
Horicon Waterworks
WI1140146 · 3,682 served
Bloomer Waterworks
WI6090448 · 3,680 served
Hobart Waterworks S a 1
WI4051698 · 3,670 served
Omro Waterworks
WI4710357 · 3,629 served
Combined Locks Waterworks
WI4450409 · 3,609 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