Wisconsin Radon Zone Map
Counties colored by EPA radon zone. Red = Zone 1, Orange = Zone 2, Green = Zone 3.
Highest-Risk Counties
BuffaloZone 1 — High
CrawfordZone 1 — High
Dane32% above action level
Dodge50% above action level
DoorZone 1 — High
Fond du Lac43.5% above action level
Grant55.6% above action level
GreenZone 1 — High
Green LakeZone 1 — High
IowaZone 1 — High
Jefferson28.6% above action level
LafayetteZone 1 — High
+16 more
All 72 Counties — By Radon Risk
| County | EPA Zone | Tests | % Above 4 pCi/L |
|---|
| Buffalo |
High |
— |
— |
| Crawford |
High |
4 |
— |
| Dane |
High |
75 |
32% |
| Dodge |
High |
16 |
50% |
| Door |
High |
8 |
— |
| Fond du Lac |
High |
23 |
43.5% |
| Grant |
High |
9 |
55.6% |
| Green |
High |
7 |
— |
| Green Lake |
High |
5 |
— |
| Iowa |
High |
5 |
— |
| Jefferson |
High |
14 |
28.6% |
| Lafayette |
High |
— |
— |
| Langlade |
High |
4 |
— |
| Marathon |
High |
25 |
36% |
| Menominee |
High |
— |
— |
| Pepin |
High |
— |
— |
| Pierce |
High |
6 |
— |
| Portage |
High |
12 |
33.3% |
| Richland |
High |
— |
— |
| Rock |
High |
29 |
37.9% |
| Shawano |
High |
10 |
50% |
| St. Croix |
High |
13 |
30.8% |
| Vernon |
High |
6 |
— |
| Walworth |
High |
21 |
47.6% |
| Washington |
High |
20 |
45% |
| Waukesha |
High |
80 |
30% |
| Waupaca |
High |
12 |
50% |
| Wood |
High |
15 |
40% |
| Adams |
Moderate |
7 |
— |
| Ashland |
Moderate |
— |
— |
| Barron |
Moderate |
10 |
50% |
| Bayfield |
Moderate |
— |
— |
| Brown |
Moderate |
37 |
45.9% |
| Burnett |
Moderate |
4 |
— |
| Calumet |
Moderate |
7 |
— |
| Chippewa |
Moderate |
14 |
35.7% |
| Clark |
Moderate |
7 |
— |
| Columbia |
Moderate |
10 |
40% |
| Douglas |
Moderate |
8 |
50% |
| Dunn |
Moderate |
6 |
— |
| Eau Claire |
Moderate |
17 |
41.2% |
| Florence |
Moderate |
— |
— |
| Forest |
Moderate |
— |
— |
| Iron |
Moderate |
— |
— |
| Jackson |
Moderate |
4 |
— |
| Juneau |
Moderate |
5 |
— |
| Kenosha |
Moderate |
26 |
42.3% |
| Kewaunee |
Moderate |
5 |
— |
| La Crosse |
Moderate |
17 |
41.2% |
| Lincoln |
Moderate |
6 |
— |
| Manitowoc |
Moderate |
16 |
50% |
| Marinette |
Moderate |
12 |
33.3% |
| Marquette |
Moderate |
5 |
— |
| Milwaukee |
Moderate |
161 |
36% |
| Monroe |
Moderate |
7 |
— |
| Oconto |
Moderate |
9 |
55.6% |
| Oneida |
Moderate |
9 |
44.4% |
| Outagamie |
Moderate |
27 |
40.7% |
| Ozaukee |
Moderate |
18 |
38.9% |
| Polk |
Moderate |
11 |
36.4% |
| Price |
Moderate |
— |
— |
| Racine |
Moderate |
32 |
37.5% |
| Rusk |
Moderate |
4 |
— |
| Sauk |
Moderate |
14 |
28.6% |
| Sawyer |
Moderate |
4 |
— |
| Sheboygan |
Moderate |
22 |
40.9% |
| Taylor |
Moderate |
— |
— |
| Trempealeau |
Moderate |
4 |
100% |
| Vilas |
Moderate |
7 |
— |
| Washburn |
Moderate |
4 |
— |
| Waushara |
Moderate |
6 |
— |
| Winnebago |
Moderate |
28 |
46.4% |
Sources: EPA Map of Radon Zones, CDC Environmental Health Tracking Network
Frequently Asked Questions
How many counties in Wisconsin have high radon risk?
Wisconsin has 28 counties classified as EPA Zone 1 (high radon risk), 44 as Zone 2 (moderate), and 0 as Zone 3 (low risk).
Is radon a problem in Wisconsin?
Wisconsin has 28 high-risk counties where elevated radon is likely. The EPA recommends all homes in Wisconsin be tested for radon, regardless of which zone they're in.
How do I check radon levels for my Wisconsin address?
Enter your ZIP code in the search box above to see your county's EPA radon zone and available testing data. For your specific home's radon level, you'll need a radon test kit.