Carter County, KY: EPA's radon zone, explained

EPA places Carter 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. Nationally, Carter County ranks higher in radon potential than 49% of rated counties (the 49th percentile).

Carter County by the numbers

Carter County, Kentucky is home to about 26,098 people across 409.497 square miles. That works out to roughly 64 people per square mile. By population, Carter County is the 535th largest of every county sharing its EPA zone — the 48th percentile by population within that zone. Geologically, Carter County is grouped into EPA Region 4 alongside 735 other counties that share its rock and soil setting.

What this actually means for a house in Carter County

EPA's Zone 2 rating for Carter County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. A county-wide moderate average, like Carter County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Next steps for a home in Carter County

For a Carter 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 Kentucky's state radon program

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

Where Carter County's figures come from

Carter County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Carter County carries, the zone explainer covers what it does and doesn't tell you about any one house.