What EPA's radon map says about Dearborn County

EPA places Dearborn 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. Dearborn County sits at the 55th percentile nationally for radon potential — above 55 of every 100 rated counties.

How Dearborn County compares

About 51,435 people live in Dearborn County, Indiana, spread over 305.087 square miles. That works out to roughly 169 people per square mile. Among counties sharing Dearborn County's EPA zone, it outranks 67% of them by population. EPA's geology-based Region 5 groups Dearborn County with 523 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Dearborn County

Neither at the 4 pCi/L action level nor down at the roughly 1.3 pCi/L national indoor norm, Dearborn County's Zone 2 prediction lands in the gap between the two. Middle-of-the-pack doesn't mean risk-free for any one Dearborn County address — a moderate county average still leaves individual homes to test either side of it.

Next steps for a home in Dearborn County

Mitigation cost doesn't depend on Dearborn 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

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

More on how this number was built

The methodology guide shows exactly which EPA and Census sources feed Dearborn County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.