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

EPA's own radon map rates Nelson County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally, Nelson County ranks higher in radon potential than 90% of rated counties (the 90th percentile).

Where Nelson County sits nationally

Nelson County, Kentucky is home to about 48,706 people across 418.686 square miles. That works out to roughly 116 people per square mile. By population, Nelson County is the 321st largest of every county sharing its EPA zone — the 70th percentile by population within that zone. Geologically, Nelson County is grouped into EPA Region 4 alongside 735 other counties that share its rock and soil setting.

Zone vs. an actual test

Nelson County's predicted average sits above EPA's own action level of 4 pCi/L — the concentration at which EPA recommends fixing a home — versus a national average around 1.3 pCi/L indoors and 0.4 pCi/L outdoors. EPA's guidance doesn't change because of a Zone 1 label: test the house. What changes is the reason to not put it off in Nelson County specifically.

Next steps for a home in Nelson County

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

Where Nelson County's figures come from

The methodology guide shows exactly which EPA and Census sources feed Nelson County's numbers. Whatever zone Nelson County carries, the zone explainer covers what it does and doesn't tell you about any one house.