Carlisle County, KY: EPA's radon zone, explained
Carlisle County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. That puts Carlisle County in the 3rd percentile nationally for radon potential — higher than 3% of the counties EPA has rated.
Where Carlisle County sits nationally
Carlisle County, Kentucky is home to about 4,777 people across 189.463 square miles. Population density there runs about 25 people per square mile. By population, Carlisle County is the 947th largest of every county sharing its EPA zone — the 8th percentile by population within that zone. Carlisle County falls in EPA Radon Region 4, one of 736 counties nationally EPA assigns to that same geologic province.
Why the zone isn't the answer by itself
Carlisle County's Zone 3 prediction undercuts the roughly 1.3 pCi/L most US homes average, nowhere near EPA's 4 pCi/L threshold for recommending mitigation. A Zone 3 rating means Carlisle County's county-wide average is predicted low, but EPA is explicit that a meaningful share of homes in low-potential zones still test above the action level — a low zone is not a reason to skip testing.
Next steps for a home in Carlisle County
For a Carlisle 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 Carlisle County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Carlisle County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.
Where Carlisle County's figures come from
Carlisle County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.