State Hub
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
76–100 of 493Greenville Utilities Vil of
WI4450278 · 11,340 served
Two Rivers Waterworks
WI4360436 · 11,270 served
Oregon Waterworks
WI1130251 · 11,200 served
Mequon Water Utility
WI2460112 · 11,152 served
Marinette Waterworks
WI4380395 · 10,968 served
Fox Crossing Utilities East
WI4710453 · 10,927 served
New Richmond Waterworks
WI6560126 · 10,824 served
Monroe Waterworks
WI1230078 · 10,780 served
Pleasant Prairie Water Utility
WI2300167 · 10,754 served
Deforest Waterworks
WI1130221 · 10,500 served
Portage Waterworks
WI1110039 · 10,437 served
Elkhorn Waterworks
WI2650062 · 10,317 served
Holmen Waterworks
WI6320306 · 10,147 served
Sparta Waterworks
WI6420297 · 10,025 served
Fort Mccoy North Post
WI6420302 · 10,000 served
Reedsburg Waterworks
WI1570102 · 9,984 served
Burlington Waterworks
WI2520177 · 9,958 served
Sturgeon Bay Waterworks
WI4150526 · 9,700 served
Mcfarland Waterworks
WI1130241 · 9,676 served
Merrill Waterworks
WI7350123 · 9,661 served
Altoona Waterworks
WI6180280 · 9,627 served
Shawano Waterworks
WI4590456 · 9,610 served
Cottage Grove Waterworks
WI1130218 · 9,345 served
Hartland Waterworks
WI2680205 · 9,212 served
Tomah Waterworks
WI6420254 · 9,192 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
Quick Links
Data source: Utility data from EPA SDWIS. 493 active community water systems ingested. CCR contaminant data ingestion in progress.
Last updated: 2026-04-19