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

EPA's own radon map rates Green County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. That puts Green County in the 77th percentile nationally for radon potential — higher than 77% of the counties EPA has rated.

Green County by the numbers

Green County, Kentucky is home to about 11,552 people across 285.963 square miles. That works out to roughly 40 people per square mile. By population, Green County is the 731st largest of every county sharing its EPA zone — the 31st percentile by population within that zone. EPA's geology-based Region 4 groups Green County with 735 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Where the national indoor average runs about 1.3 pCi/L, Green County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. Some Green County homes will test comfortably under the action level despite the county's Zone 1 rating — the only way to know which kind of home you have is an actual test.

Next steps for a home in Green County

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

Where Green County's figures come from

The methodology guide shows exactly which EPA and Census sources feed Green County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.