Radon in Indiana

Of Indiana's 92 counties and county equivalents, EPA places 57 in Zone 1, 35 in Zone 2. Zones are county-wide predictions; testing is the only way to know your home's level.

Radon in the news

Indiana stories

Test Your Home for Radon: High Levels of Cancer-Causing Gas Found in 40% of Indiana Homes
American Lung Association · 2026-01-23

Headlines link to the original publishers via Google News. Updated 2026-10-27.

All 92 counties

County	EPA 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
DeKalb County	Zone 1
Dearborn County	Zone 2
Decatur 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
LaPorte County	Zone 2
Lake 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

Source: EPA radon zones spreadsheet (EPA 402/A-16/001).