Wisconsin has 70 counties, with 26 classified as EPA Zone 1 (highest risk). With an average radon level of 7.93 pCi/L, Wisconsin state testing data reveals significantly elevated risks across multiple counties. Testing is highly recommended.
Wisconsin is the 23rd most expansive state in terms of size and the 20th most populous.
Wisconsin does have an active radon program, dedicated to educating citizens about the risks associated with the deadly gas. You can find more information on Radon, testing and mitigation at the official page.
Explore radon data organized by metro region, including average levels, hotspot cities, and local mitigation professionals.
Cities with the most user-submitted radon test data, ranked by number of submissions.
| City | Avg User Radon Level | Submissions |
|---|---|---|
| Milwaukee | 10.00 pCi/L | 3 |
| Prairie Du Chien | 10.00 pCi/L | 2 |
| Stevens Point | 5.50 pCi/L | 2 |
| Menomonie | 10.00 pCi/L | 1 |
| Delavan | 6.00 pCi/L | 1 |
| Shawano | No submissions | 0 |
| Sturgeon Bay | No submissions | 0 |
All 70 Wisconsin counties with their EPA radon zone classification and user-submitted average radon levels.
Browse radon data for individual cities across Wisconsin. Each city page includes user-submitted radon levels, local contractors, and mitigation resources.