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National Drinking Water Database


Radon in Wisconsin


Radon is a radioactive breakdown product of radium and uranium in soil, rock and water; it is often present in groundwater. [read more]

The Most Polluted Communities in Wisconsin

81 water utilities reported detecting Radon in tap water since 2004, according to EWG's analysis of water quality data supplied by state water agencies

Ranked by highest average Radon level

RankSystem Population Served Positive test results of total reported tests Average Level
(Range)
1Colby Waterworks
Colby, WI
1,6001 of 113900 pCi/L
(13900 pCi/L)
2Bethel Nursing & Rehab Center
Arpin, WI
2252 of 29450 pCi/L
(6800 to 12100 pCi/L)
3Mattoon Waterworks
Mattoon, WI
4501 of 12390 pCi/L
(2390 pCi/L)
4Thorp Waterworks
Thorp, WI
1,5651 of 11650.85 pCi/L
(1650.85 pCi/L)
5Village of Lake Hallie Waterworks
Chippewa Falls, WI
3,5002 of 21625 pCi/L
(1560 to 1690 pCi/L)
6Gresham Waterworks
Gresham, WI
5346 of 6884.1 pCi/L
(44.9 to 4930 pCi/L)
7City of Hayward Water Utility
Hayward, WI
2,3132 of 2769 pCi/L
(538 to 1000 pCi/L)
8St Croix Falls Waterworks
St Croix Falls, WI
2,0791 of 1738 pCi/L
(738 pCi/L)
9Hixton Waterworks
Hixton, WI
4431 of 1583 pCi/L
(583 pCi/L)
10Lake Delton Waterworks
Lake Delton, WI
2,5991 of 1568.7 pCi/L
(568.7 pCi/L)

Health Based Limits for Radon

StandardDescriptionLevel
One in one million (10-6) Cancer RiskThe concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 1,000,000. Source: U.S. Environmental Protection Agency.1.5 pCi/L
One in ten thousand (10-4) Cancer RiskThe concentration of a chemical in drinking water corresponding to an excess estimated lifetime cancer risk of 1 in 10,000. Source: U.S. Environmental Protection Agency.150 pCi/L

Violation Summary for Radon in Wisconsin

There are no violations reported for this contaminant in Wisconsin