Is Columbiana County, OH a radon risk area?

EPA's own radon map rates Columbiana County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Columbiana County sits at the 94th percentile nationally for radon potential — above 94 of every 100 rated counties.

Where Columbiana County sits nationally

About 99,823 people live in Columbiana County, Ohio, spread over 531.93 square miles. Population density there runs about 188 people per square mile. Rank 195 by population within its EPA zone puts Columbiana County at the 82nd percentile among zone peers. Geologically, Columbiana County is grouped into EPA Region 5 alongside 523 other counties that share its rock and soil setting.

What this actually means for a house in Columbiana County

Fixing a home becomes an EPA recommendation past 4 pCi/L, and that is precisely the side of the line Columbiana 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 Columbiana County will test well under the action level, and EPA's guidance is to test regardless of zone.

Testing and mitigation in Columbiana County

Nothing about Columbiana 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

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

More on how this number was built

Columbiana County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Columbiana County carries, the zone explainer covers what it does and doesn't tell you about any one house.