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

EPA's own radon map rates Hart County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally that's the 82nd percentile for radon potential — Hart County outranks 82% of every county EPA has rated.

Hart County by the numbers

Hart County, Kentucky is home to about 19,923 people across 412.67 square miles. Population density there runs about 48 people per square mile. By population, Hart County is the 574th largest of every county sharing its EPA zone — the 46th percentile by population within that zone. Geologically, Hart County is grouped into EPA Region 4 alongside 735 other counties that share its rock and soil setting.

Zone vs. an actual test

Where the national indoor average runs about 1.3 pCi/L, Hart County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. Some Hart 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.

If Hart County tests above the action level

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

Where Hart County's figures come from

Hart 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.