Clark County, KY radon potential
EPA's own radon map rates Clark County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally that's the 87th percentile for radon potential — Clark County outranks 87% of every county EPA has rated.
Where Clark County sits nationally
Clark County, Kentucky is home to about 37,673 people across 252.482 square miles. Averaged across its land area, Clark County runs about 149 people per square mile. Within its own EPA zone, Clark County is bigger by population than 63% of the counties that share it. Clark County falls in EPA Radon Region 4, one of 736 counties nationally EPA assigns to that same geologic province.
Zone vs. an actual test
Fixing a home becomes an EPA recommendation past 4 pCi/L, and that is precisely the side of the line Clark County's Zone 1 prediction lands on, well above the roughly 1.3 pCi/L most US homes average. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Clark County will test well under the action level, and EPA's guidance is to test regardless of zone.
Testing and mitigation in Clark County
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 Clark County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Clark 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 Clark County's figures come from
The methodology guide shows exactly which EPA and Census sources feed Clark County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.