Is Highland County, OH a radon risk area?

EPA's own radon map rates Highland County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Nationally that's the 54th percentile for radon potential — Highland County outranks 54% of every county EPA has rated.

How Highland County compares

About 43,785 people live in Highland County, Ohio, spread over 553.084 square miles. That works out to roughly 79 people per square mile. Rank 377 by population within its EPA zone puts Highland County at the 64th percentile among zone peers. Highland County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.

What this actually means for a house in Highland County

Highland 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). A county-wide moderate average, like Highland 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 Highland County

Nothing about Highland County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find Ohio's state radon program

Highland County's test kit answers today; a Airthings radon monitor keeps answering for Highland County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

More on how this number was built

The methodology guide shows exactly which EPA and Census sources feed Highland County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.