Adair County, MO: EPA's radon zone, explained

EPA's own radon map rates Adair County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. That puts Adair County in the 48th percentile nationally for radon potential — higher than 48% of the counties EPA has rated.

Where Adair County sits nationally

Adair County, Missouri is home to about 25,660 people across 567.324 square miles. Averaged across its land area, Adair County runs about 45 people per square mile. By population, Adair County is the 547th largest of every county sharing its EPA zone — the 47th percentile by population within that zone. Adair County falls in EPA Radon Region 7, one of 412 counties nationally EPA assigns to that same geologic province.

What this actually means for a house in Adair County

Adair 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. Nothing about a Zone 2 label lowers the case for testing in Adair County — EPA recommends it in every zone, moderate included.

If Adair County tests above the action level

For a Adair County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find Missouri's state radon program

For Adair County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Adair County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

Where Adair County's figures come from

The methodology guide shows exactly which EPA and Census sources feed Adair County's numbers. Whatever zone Adair County carries, the zone explainer covers what it does and doesn't tell you about any one house.