What EPA's radon map says about Perry County

EPA's own radon map rates Perry County zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. Nationally that's the 8th percentile for radon potential — Perry County outranks 8% of every county EPA has rated.

Perry County by the numbers

About 11,406 people live in Perry County, Mississippi, spread over 647.274 square miles. Averaged across its land area, Perry County runs about 18 people per square mile. Among counties sharing Perry County's EPA zone, it outranks 24% of them by population. EPA's geology-based Region 4 groups Perry County with 735 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

Well clear of both the 1.3 pCi/L national indoor average and EPA's 4 pCi/L action level, Perry County's Zone 3 prediction is the low end of the scale. A Zone 3 rating means Perry County's county-wide average is predicted low, but EPA is explicit that a meaningful share of homes in low-potential zones still test above the action level — a low zone is not a reason to skip testing.

If Perry County tests above the action level

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 Mississippi'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. 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 Perry County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.