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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
426–450 of 493Crystal Lake Rv Resort Llc
WI1110066 · 725 served
Hale Park Meadows
WI2680216 · 720 served
Cascade Waterworks
WI4600436 · 719 served
Reeseville Waterworks
WI1140153 · 718 served
Montfort Waterworks
WI1220110 · 718 served
Potosi Waterworks
WI1220117 · 718 served
La Farge Waterworks
WI6630258 · 712 served
Wauzeka Waterworks
WI6120253 · 711 served
Almena Waterworks
WI6030124 · 705 served
St Nazianz Waterworks
WI4360433 · 705 served
Birch Terrace Mobile Home Community
WI6170270 · 700 served
Durham Meadows Water Trust
WI2680213 · 700 served
Saddle Ridge Estates
WI1110123 · 700 served
Ridgeway Waterworks
WI1250087 · 690 served
Bloomington Waterworks
WI1220085 · 682 served
Viola Waterworks
WI6630269 · 667 served
Livingston Waterworks
WI1220109 · 664 served
Prentice Waterworks
WI8510132 · 660 served
Hobart Waterworks S a 3
WI4052077 · 658 served
Norwalk Waterworks
WI6420296 · 653 served
Webster Waterworks
WI8070312 · 652 served
Greenleaf Waterworks
WI4050466 · 650 served
Stockbridge Waterworks
WI4080407 · 650 served
Rock River Leisure Estates Coop
WI1540167 · 650 served
Rockland Waterworks
WI6320333 · 642 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.
Wisconsin Water FAQs
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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