Iowa Radon Zone Map
Counties colored by EPA radon zone. Red = Zone 1, Orange = Zone 2, Green = Zone 3.
Highest-Risk Counties
AdairZone 1 — High
AdamsZone 1 — High
AllamakeeZone 1 — High
AppanooseZone 1 — High
AudubonZone 1 — High
BentonZone 1 — High
Black Hawk45.5% above action level
BooneZone 1 — High
BremerZone 1 — High
BuchananZone 1 — High
Buena VistaZone 1 — High
ButlerZone 1 — High
+87 more
All 99 Counties — By Radon Risk
| County | EPA Zone | Tests | % Above 4 pCi/L |
|---|
| Adair |
High |
— |
— |
| Adams |
High |
— |
— |
| Allamakee |
High |
— |
— |
| Appanoose |
High |
— |
— |
| Audubon |
High |
— |
— |
| Benton |
High |
5 |
— |
| Black Hawk |
High |
22 |
45.5% |
| Boone |
High |
5 |
— |
| Bremer |
High |
5 |
— |
| Buchanan |
High |
4 |
— |
| Buena Vista |
High |
— |
— |
| Butler |
High |
— |
— |
| Calhoun |
High |
— |
— |
| Carroll |
High |
5 |
— |
| Cass |
High |
4 |
— |
| Cedar |
High |
4 |
— |
| Cerro Gordo |
High |
10 |
50% |
| Cherokee |
High |
— |
— |
| Chickasaw |
High |
— |
— |
| Clarke |
High |
— |
— |
| Clay |
High |
5 |
— |
| Clayton |
High |
— |
— |
| Clinton |
High |
10 |
50% |
| Crawford |
High |
— |
— |
| Dallas |
High |
11 |
36.4% |
| Davis |
High |
— |
— |
| Decatur |
High |
— |
— |
| Delaware |
High |
4 |
— |
| Des Moines |
High |
9 |
44.4% |
| Dickinson |
High |
4 |
— |
| Dubuque |
High |
16 |
50% |
| Emmet |
High |
— |
— |
| Fayette |
High |
— |
— |
| Floyd |
High |
5 |
— |
| Franklin |
High |
— |
— |
| Fremont |
High |
— |
— |
| Greene |
High |
— |
— |
| Grundy |
High |
— |
— |
| Guthrie |
High |
— |
— |
| Hamilton |
High |
— |
— |
| Hancock |
High |
— |
— |
| Hardin |
High |
— |
— |
| Harrison |
High |
— |
— |
| Henry |
High |
4 |
— |
| Howard |
High |
— |
— |
| Humboldt |
High |
— |
— |
| Ida |
High |
— |
— |
| Iowa |
High |
— |
— |
| Jackson |
High |
4 |
— |
| Jasper |
High |
6 |
66.7% |
| Jefferson |
High |
— |
— |
| Johnson |
High |
17 |
35.3% |
| Jones |
High |
— |
— |
| Keokuk |
High |
— |
— |
| Kossuth |
High |
— |
— |
| Lee |
High |
10 |
— |
| Linn |
High |
35 |
40% |
| Louisa |
High |
— |
— |
| Lucas |
High |
— |
— |
| Lyon |
High |
— |
— |
| Madison |
High |
— |
— |
| Mahaska |
High |
4 |
— |
| Marion |
High |
6 |
— |
| Marshall |
High |
8 |
— |
| Mills |
High |
— |
— |
| Mitchell |
High |
— |
— |
| Monona |
High |
— |
— |
| Monroe |
High |
— |
— |
| Montgomery |
High |
— |
— |
| Muscatine |
High |
9 |
— |
| O'Brien |
High |
— |
— |
| Osceola |
High |
— |
— |
| Page |
High |
4 |
— |
| Palo Alto |
High |
— |
— |
| Plymouth |
High |
5 |
— |
| Pocahontas |
High |
— |
— |
| Polk |
High |
69 |
44.9% |
| Pottawattamie |
High |
19 |
36.8% |
| Poweshiek |
High |
— |
— |
| Ringgold |
High |
— |
— |
| Sac |
High |
4 |
— |
| Scott |
High |
33 |
36.4% |
| Shelby |
High |
— |
— |
| Sioux |
High |
5 |
— |
| Story |
High |
11 |
45.5% |
| Tama |
High |
— |
— |
| Taylor |
High |
— |
— |
| Union |
High |
— |
— |
| Van Buren |
High |
— |
— |
| Wapello |
High |
7 |
71.4% |
| Warren |
High |
5 |
80% |
| Washington |
High |
4 |
— |
| Wayne |
High |
— |
— |
| Webster |
High |
8 |
— |
| Winnebago |
High |
— |
— |
| Winneshiek |
High |
— |
— |
| Woodbury |
High |
16 |
43.8% |
| Worth |
High |
— |
— |
| Wright |
High |
— |
— |
Sources: EPA Map of Radon Zones, CDC Environmental Health Tracking Network
Frequently Asked Questions
How many counties in Iowa have high radon risk?
Iowa has 99 counties classified as EPA Zone 1 (high radon risk), 0 as Zone 2 (moderate), and 0 as Zone 3 (low risk).
Is radon a problem in Iowa?
Iowa has 99 high-risk counties where elevated radon is likely. The EPA recommends all homes in Iowa be tested for radon, regardless of which zone they're in.
How do I check radon levels for my Iowa 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.