Franklin County, KY radon potential

EPA places Franklin County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Rank it against the rest of the country and Franklin County lands in the 90th percentile for radon potential.

How Franklin County compares

Franklin County, Kentucky is home to about 52,442 people across 207.912 square miles. That works out to roughly 252 people per square mile. Within its own EPA zone, Franklin County is bigger by population than 72% of the counties that share it. EPA's geology-based Region 4 groups Franklin County with 735 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Franklin County carries a Zone 1 label because its predicted average clears 4 pCi/L outright — three-plus times the 0.4 pCi/L typical outdoors and above the 1.3 pCi/L most homes see. Some Franklin 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 Franklin County tests above the action level

A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.

Find Kentucky's state radon program

For Franklin County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Franklin 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 Franklin 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 Franklin County carries, the zone explainer covers what it does and doesn't tell you about any one house.