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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
326–350 of 493Fall Creek Waterworks
WI6180296 · 1,269 served
Gillett Waterworks
WI4430490 · 1,264 served
Theresa Waterworks
WI1140154 · 1,262 served
Barneveld Waterworks
WI1250075 · 1,258 served
Florence Utility Commission
WI4190155 · 1,250 served
Iola Waterworks
WI4690394 · 1,249 served
Frederic Waterworks
WI6490337 · 1,241 served
Wisconsin Veterans Home
WI4690395 · 1,240 served
Shullsburg Waterworks
WI1330076 · 1,222 served
Monticello Waterworks
WI1230083 · 1,217 served
Rockvale Mhp
WI1540126 · 1,200 served
Lakeland University
WI4600487 · 1,200 served
Reedsville Waterworks
WI4360431 · 1,200 served
Wittenberg Waterworks
WI4590465 · 1,200 served
Hazel Green Waterworks
WI1220102 · 1,193 served
Hilbert Waterworks
WI4080269 · 1,176 served
Princeton Waterworks
WI4240219 · 1,166 served
Luck Waterworks
WI6490338 · 1,150 served
Cashton Waterworks
WI6420294 · 1,120 served
Amherst Waterworks
WI7500094 · 1,119 served
Dane Waterworks
WI1130220 · 1,117 served
Colfax Waterworks
WI6170261 · 1,102 served
Glenwood City Waterworks
WI6560120 · 1,102 served
Strum Waterworks
WI6620331 · 1,100 served
Oakhill Correctional Inst
WI1130250 · 1,096 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