Clarke County, AL: EPA's radon zone, explained

Clarke County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. Nationally, Clarke County ranks higher in radon potential than 15% of rated counties (the 15th percentile).

Clarke County by the numbers

Clarke County, Alabama is home to about 22,142 people across 1,238.42 square miles. That works out to roughly 18 people per square mile. By population, Clarke County is the 575th largest of every county sharing its EPA zone — the 44th percentile by population within that zone. Clarke County falls in EPA Radon Region 4, one of 736 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

A Zone 3 county like Clarke County is predicted closer to the 0.4 pCi/L typical outdoors than to EPA's 4 pCi/L action level. Low doesn't mean zero: EPA's own data shows homes in Zone 3 counties like Clarke County testing above the action level often enough that skipping a test isn't the safe assumption.

If Clarke County tests above the action level

For a Clarke 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 Alabama's state radon program

For Clarke County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Clarke 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 Clarke County's figures come from

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