Is Ross County, OH a radon risk area?

EPA's own radon map rates Ross County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. That puts Ross County in the 93rd percentile nationally for radon potential — higher than 93% of the counties EPA has rated.

How Ross County compares

About 76,046 people live in Ross County, Ohio, spread over 689.166 square miles. Averaged across its land area, Ross County runs about 110 people per square mile. Rank 233 by population within its EPA zone puts Ross County at the 78th percentile among zone peers. EPA's geology-based Region 5 groups Ross County with 523 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Where the national indoor average runs about 1.3 pCi/L, Ross County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. EPA's guidance doesn't change because of a Zone 1 label: test the house. What changes is the reason to not put it off in Ross County specifically.

Next steps for a home in Ross County

Nothing about Ross 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

Ross County's test kit answers today; a Airthings radon monitor keeps answering for Ross 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 Ross County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.