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

EPA places Clay 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. Clay County sits at the 46th percentile nationally for radon potential — above 46 of every 100 rated counties.

How Clay County compares

Clay County, Kentucky is home to about 19,592 people across 469.296 square miles. Population density there runs about 42 people per square mile. By population, Clay County is the 635th largest of every county sharing its EPA zone — the 39th percentile by population within that zone. Geologically, Clay 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 Clay County

EPA's Zone 2 rating for Clay County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. Clay County's Zone 2 rating sits in the middle nationally; EPA's guidance is unchanged by that — test every home regardless of its zone.

If Clay County tests above the action level

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

Where Clay County's figures come from

Clay 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.