Radon Risk in Indiana

EPA zone data and CDC radon averages for all 92 counties in Indiana.

5.27 pCi/L
Statewide avg
57
Zone 1 counties
35
Zone 2 counties
0
Zone 3 counties
T

Tipper on radon in Indiana

Indiana has a statewide average radon level of 5.27 pCi/L, above the EPA's action level of 4 pCi/L. That puts Indiana among the higher-risk states in the country for indoor radon. If you live here, testing your home is genuinely important.

Looking at the zone breakdown: 57 of Indiana's 92 counties are EPA Zone 1 (high risk), 35 are Zone 2 (moderate). That means 62% of the state falls into the highest risk category, counties where the EPA predicts average indoor levels above 4 pCi/L. Use the county list below to find your area and see the most specific data available.

Within Indiana, the spread is notable. Rush County has the highest measured average in the state at 14.6 pCi/L. Starke County sits at the other end with 1.9 pCi/L. 72 counties have a measured average above 4 pCi/L. Remember: these are averages. Individual homes can test significantly higher or lower than their county average depending on construction, foundation type, and ventilation.

Tipper's recommendation for Indiana residents: if you haven't tested your home, start there. A short-term test kit costs around $15 and gives you a result in 48 hours. If your home tests at or above 4 pCi/L, a professional mitigation system (typically $800–$2,000 depending on your foundation and home size) will reliably bring levels down.

Sources: EPA Radon Zone Map, CDC Environmental Public Health Tracking Network

Why Indiana's Geology Matters

Indiana's radon risk is driven by carbonate bedrock — limestone and dolomite — that underlies much of the state, combined with glacial till in the north. The karst terrain in south-central Indiana, with its caves and sinkholes, creates direct pathways for radon migration. Northern counties on thick glacial deposits also tend to run high.

Radon Disclosure Laws

Indiana's Residential Real Estate Disclosure law requires sellers to disclose known radon levels and the presence of any radon mitigation systems.

State Radon Program

Indiana State Department of Health — Radon Program

All Counties in Indiana

Click any county to see its full radon data and local contractors.

Adams County
6.8 pCi/LZ1
Allen County
5 pCi/LZ1
Bartholomew County
5.6 pCi/LZ1
Benton County
8.5 pCi/LZ1
Blackford County
3.6 pCi/LZ1
Boone County
4.4 pCi/LZ1
Brown County
3.6 pCi/LZ2
Carroll County
8.4 pCi/LZ1
Cass County
4.9 pCi/LZ1
Clark County
9.2 pCi/LZ1
Clay County
4.2 pCi/LZ2
Clinton County
5.1 pCi/LZ1
Crawford County
4.1 pCi/LZ2
Daviess County
4.2 pCi/LZ2
Dearborn County
3.7 pCi/LZ2
Decatur County
4.4 pCi/LZ1
Dekalb County
6 pCi/LZ1
Delaware County
6.4 pCi/LZ1
Dubois County
4.4 pCi/LZ2
Elkhart County
5.1 pCi/LZ1
Fayette County
8.9 pCi/LZ1
Floyd County
5.6 pCi/LZ2
Fountain County
7.7 pCi/LZ1
Franklin County
3.6 pCi/LZ2
Fulton County
6 pCi/LZ1
Gibson County
4.9 pCi/LZ2
Grant County
7.7 pCi/LZ1
Greene County
3.6 pCi/LZ2
Hamilton County
4.5 pCi/LZ1
Hancock County
3.9 pCi/LZ1
Harrison County
10.2 pCi/LZ1
Hendricks County
4.8 pCi/LZ1
Henry County
6.7 pCi/LZ1
Howard County
5.4 pCi/LZ1
Huntington County
4.6 pCi/LZ1
Jackson County
3.5 pCi/LZ2
Jasper County
2.2 pCi/LZ2
Jay County
3.5 pCi/LZ1
Jefferson County
5.5 pCi/LZ2
Jennings County
4.2 pCi/LZ1
Johnson County
4.5 pCi/LZ1
Knox County
4.1 pCi/LZ2
Kosciusko County
6 pCi/LZ1
Lagrange County
4.7 pCi/LZ1
Lake County
2.9 pCi/LZ2
Laporte County
8.8 pCi/LZ2
Lawrence County
5.6 pCi/LZ1
Madison County
6.3 pCi/LZ1
Marion County
4.6 pCi/LZ1
Marshall County
4.7 pCi/LZ1
Martin County
5.7 pCi/LZ2
Miami County
8 pCi/LZ1
Monroe County
4.4 pCi/LZ1
Montgomery County
5.5 pCi/LZ1
Morgan County
5.1 pCi/LZ2
Newton County
2.2 pCi/LZ2
Noble County
8.4 pCi/LZ1
Ohio County
4.8 pCi/LZ2
Orange County
6.2 pCi/LZ1
Owen County
4.4 pCi/LZ2
Parke County
5.8 pCi/LZ2
Perry County
3.4 pCi/LZ2
Pike County
4 pCi/LZ2
Porter County
7 pCi/LZ2
Posey County
4.1 pCi/LZ2
Pulaski County
4.1 pCi/LZ2
Putnam County
4.6 pCi/LZ1
Randolph County
6.5 pCi/LZ1
Ripley County
3.6 pCi/LZ2
Rush County
14.6 pCi/LZ1
Scott County
3.7 pCi/LZ1
Shelby County
5.6 pCi/LZ1
Spencer County
5.3 pCi/LZ2
St. Joseph County
3.8 pCi/LZ1
Starke County
1.9 pCi/LZ2
Steuben County
5.9 pCi/LZ1
Sullivan County
3.5 pCi/LZ2
Switzerland County
4.3 pCi/LZ2
Tippecanoe County
5 pCi/LZ1
Tipton County
4.7 pCi/LZ1
Union County
6 pCi/LZ1
Vanderburgh County
3.1 pCi/LZ2
Vermillion County
6.1 pCi/LZ1
Vigo County
5.1 pCi/LZ2
Wabash County
7.6 pCi/LZ1
Warren County
4 pCi/LZ1
Warrick County
2.7 pCi/LZ2
Washington County
5.4 pCi/LZ1
Wayne County
6.5 pCi/LZ1
Wells County
5.8 pCi/LZ1
White County
3.6 pCi/LZ1
Whitley County
6.2 pCi/LZ1

Showing 92 of 92 counties in Indiana. Zone classifications from the EPA. Average pCi/L from CDC tracking data.

Not sure where to start?

A short-term test kit tells you your home's actual radon level in 48 hours. Tipper has picked the best options at every price point. All EPA-approved, all lab-fee included.

See Tipper's Test Kit Picks

Contractors

Find certified radon pros in Indiana

Guides

Search

← Search a different county