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

Oldham County is mapped as Zone 2 - Moderate Potential by EPA — meaning the county-wide average indoor level is predicted between 2 and 4 pCi/L. Nationally, Oldham County ranks higher in radon potential than 58% of rated counties (the 58th percentile).

Where Oldham County sits nationally

Oldham County, Kentucky is home to about 70,525 people across 187.294 square miles. Population density there runs about 377 people per square mile. By population, Oldham County is the 261st largest of every county sharing its EPA zone — the 75th percentile by population within that zone. EPA's geology-based Region 4 groups Oldham County with 735 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Oldham County

Oldham County's predicted average falls between EPA's 4 pCi/L action level and the national indoor average of about 1.3 pCi/L (outdoor air runs roughly 0.4 pCi/L). Oldham 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 Oldham County tests above the action level

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

Where Oldham County's figures come from

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. Whatever zone Oldham County carries, the zone explainer covers what it does and doesn't tell you about any one house.