Radon Risk in Indiana
EPA zone data and CDC radon averages for all 92 counties in Indiana.
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.
Highest Radon Averages
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All Counties in Indiana
Click any county to see its full radon data and local contractors.
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.
Contractors
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