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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
226–250 of 493Abbotsford Waterworks
WI7370148 · 2,502 served
Belgium Waterworks
WI2460107 · 2,493 served
Mineral Point Waterworks
WI1250084 · 2,487 served
Westby Waterworks
WI6630267 · 2,400 served
Nekoosa Waterworks
WI7720169 · 2,394 served
Neillsville Waterworks
WI6100330 · 2,384 served
Lakeland Sanitary Dist 1
WI7440116 · 2,381 served
Dousman Water Utility
WI2680197 · 2,350 served
New Glarus Waterworks
WI1230084 · 2,348 served
Cumberland Waterworks
WI6030132 · 2,311 served
Walworth Waterworks
WI2650149 · 2,304 served
Wautoma Water Dept
WI4700718 · 2,280 served
Washburn Waterworks
WI8040132 · 2,280 served
Fredonia Waterworks
WI2460109 · 2,279 served
Kohler Waterworks
WI4600444 · 2,271 served
Geneva National Community Services
WI2650907 · 2,250 served
Darlington Waterworks
WI1330073 · 2,235 served
Cedar Grove Waterworks
WI4600437 · 2,213 served
Schofield Waterworks
WI7370162 · 2,205 served
Butler Waterworks
WI2680191 · 2,181 served
Pardeeville Waterworks
WI1110049 · 2,151 served
Cuba City Waterworks
WI1220092 · 2,141 served
Clinton Waterworks
WI1540114 · 2,119 served
Prairie Village Water Trust
WI2680277 · 2,100 served
St Croix Falls Waterworks
WI6490343 · 2,079 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