What EPA's radon map says about Ripley County

EPA places Ripley County in Zone 2 - Moderate Potential — a predicted county-wide average indoor radon level between 2 and 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. That puts Ripley County in the 50th percentile nationally for radon potential — higher than 50% of the counties EPA has rated.

How Ripley County compares

About 29,214 people live in Ripley County, Indiana, spread over 446.432 square miles. Averaged across its land area, Ripley County runs about 65 people per square mile. Among counties sharing Ripley County's EPA zone, it outranks 52% of them by population. Geologically, Ripley County is grouped into EPA Region 5 alongside 523 other counties that share its rock and soil setting.

What this actually means for a house in Ripley County

Ripley County's Zone 2 prediction clears the 1.3 pCi/L national indoor average without reaching EPA's own 4 pCi/L point for recommending a fix. A county-wide moderate average, like Ripley County's, can still hide a specific house well above or below it — testing is what actually answers the question.

If Ripley County tests above the action level

Mitigation cost doesn't depend on Ripley County's zone — it depends on the house's foundation. A typical system runs $800–$2,500 (about $1,200 typical), and testing first is what tells you whether that's needed at all.

Find Indiana's state radon program

Ripley County's test kit answers today; a Airthings radon monitor keeps answering for Ripley County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.

More on how this number was built

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. Whatever zone Ripley County carries, the zone explainer covers what it does and doesn't tell you about any one house.