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

EPA's own radon map rates Union County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Nationally that's the 42nd percentile for radon potential — Union County outranks 42% of every county EPA has rated.

Union County by the numbers

Union County, Kentucky is home to about 13,178 people across 342.878 square miles. Averaged across its land area, Union County runs about 38 people per square mile. By population, Union County is the 754th largest of every county sharing its EPA zone — the 27th percentile by population within that zone. EPA's geology-based Region 4 groups Union County with 735 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

EPA's Zone 2 rating for Union County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. A county-wide moderate average, like Union County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Next steps for a home in Union County

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

Where Union County's figures come from

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