What EPA's radon map says about Perry County

EPA places Perry 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 Perry County in the 46th percentile nationally for radon potential — higher than 46% of the counties EPA has rated.

Perry County by the numbers

About 19,100 people live in Perry County, Missouri, spread over 474.355 square miles. That works out to roughly 40 people per square mile. Among counties sharing Perry County's EPA zone, it outranks 38% of them by population. Perry County falls in EPA Radon Region 7, one of 412 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Perry 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. Perry County's Zone 2 rating sits in the middle nationally; EPA's guidance is unchanged by that — test every home regardless of its zone.

Next steps for a home in Perry County

Mitigation cost doesn't depend on Perry 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 Missouri's state radon program

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

More on how this number was built

The methodology guide shows exactly which EPA and Census sources feed Perry County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.