Radon zones in Indiana
Last updated
EPA’s Map of Radon Zones places 92 Indiana counties in its three radon potential zones: 57 in Zone 1 (highest), 35 in Zone 2 (moderate), and 0 in Zone 3 (low).
What this means for Indiana homes
Most Indiana counties fall in Zone 1. EPA predicts average indoor screening levels above 4 pCi/L across much of Indiana, so elevated radon is common. Testing is especially worthwhile here, and radon-resistant construction features make sense for new homes.
EPA’s guidance is the same everywhere: test your home, fix it if the level is 4 pCi/L or higher, and consider fixing between 2 and 4 pCi/L. The zone map is from 1993 and should not be used to decide whether a single home needs testing.
Indiana radon program
EPA lists the following state contact for Indiana: IN Radon Program, phone 317-232-8603. Website: www.in.gov/idem/health/common-environmental-health-threats/radon. State programs can tell you about local testing data, free or discounted test kits, disclosure rules for home sales, and credentialed radon professionals.
Indiana counties and their EPA radon zones
| County | EPA radon zone |
|---|---|
| Adams County | Zone 1 |
| Allen County | Zone 1 |
| Bartholomew County | Zone 1 |
| Benton County | Zone 1 |
| Blackford County | Zone 1 |
| Boone County | Zone 1 |
| Brown County | Zone 2 |
| Carroll County | Zone 1 |
| Cass County | Zone 1 |
| Clark County | Zone 1 |
| Clay County | Zone 2 |
| Clinton County | Zone 1 |
| Crawford County | Zone 2 |
| Daviess County | Zone 2 |
| Dearborn County | Zone 2 |
| Decatur County | Zone 1 |
| DeKalb County | Zone 1 |
| Delaware County | Zone 1 |
| Dubois County | Zone 2 |
| Elkhart County | Zone 1 |
| Fayette County | Zone 1 |
| Floyd County | Zone 2 |
| Fountain County | Zone 1 |
| Franklin County | Zone 2 |
| Fulton County | Zone 1 |
| Gibson County | Zone 2 |
| Grant County | Zone 1 |
| Greene County | Zone 2 |
| Hamilton County | Zone 1 |
| Hancock County | Zone 1 |
| Harrison County | Zone 1 |
| Hendricks County | Zone 1 |
| Henry County | Zone 1 |
| Howard County | Zone 1 |
| Huntington County | Zone 1 |
| Jackson County | Zone 2 |
| Jasper County | Zone 2 |
| Jay County | Zone 1 |
| Jefferson County | Zone 2 |
| Jennings County | Zone 1 |
| Johnson County | Zone 1 |
| Knox County | Zone 2 |
| Kosciusko County | Zone 1 |
| LaGrange County | Zone 1 |
| Lake County | Zone 2 |
| LaPorte County | Zone 2 |
| Lawrence County | Zone 1 |
| Madison County | Zone 1 |
| Marion County | Zone 1 |
| Marshall County | Zone 1 |
| Martin County | Zone 2 |
| Miami County | Zone 1 |
| Monroe County | Zone 1 |
| Montgomery County | Zone 1 |
| Morgan County | Zone 2 |
| Newton County | Zone 2 |
| Noble County | Zone 1 |
| Ohio County | Zone 2 |
| Orange County | Zone 1 |
| Owen County | Zone 2 |
| Parke County | Zone 2 |
| Perry County | Zone 2 |
| Pike County | Zone 2 |
| Porter County | Zone 2 |
| Posey County | Zone 2 |
| Pulaski County | Zone 2 |
| Putnam County | Zone 1 |
| Randolph County | Zone 1 |
| Ripley County | Zone 2 |
| Rush County | Zone 1 |
| Scott County | Zone 1 |
| Shelby County | Zone 1 |
| Spencer County | Zone 2 |
| St. Joseph County | Zone 1 |
| Starke County | Zone 2 |
| Steuben County | Zone 1 |
| Sullivan County | Zone 2 |
| Switzerland County | Zone 2 |
| Tippecanoe County | Zone 1 |
| Tipton County | Zone 1 |
| Union County | Zone 1 |
| Vanderburgh County | Zone 2 |
| Vermillion County | Zone 1 |
| Vigo County | Zone 2 |
| Wabash County | Zone 1 |
| Warren County | Zone 1 |
| Warrick County | Zone 2 |
| Washington County | Zone 1 |
| Wayne County | Zone 1 |
| Wells County | Zone 1 |
| White County | Zone 1 |
| Whitley County | Zone 1 |
County names follow the 2020 Census. Zones from the EPA Map of Radon Zones (text version). Rows marked “zone of” use the zone EPA gave the predecessor or surrounding county.
Next steps: read how to test your home, check a result with the level calculator, or look up a single address by ZIP code.