What EPA's radon map says about Columbia County

Columbia County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. Columbia County sits at the 28th percentile nationally for radon potential — above 28 of every 100 rated counties.

Columbia County by the numbers

About 167,472 people live in Columbia County, Georgia, spread over 290.194 square miles. That works out to roughly 577 people per square mile. Among counties sharing Columbia County's EPA zone, it outranks 85% of them by population. EPA's geology-based Region 4 groups Columbia 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, Columbia County's Zone 3 prediction is the low end of the scale. Don't read Zone 3 as a pass for Columbia County — EPA's guidance to test every home makes no exception for counties predicted low.

If Columbia County tests above the action level

Mitigation cost doesn't depend on Columbia 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 Georgia's state radon program

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

More on how this number was built

Columbia County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.