Champaign County, OH: EPA's radon zone, explained

EPA's own radon map rates Champaign County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. That puts Champaign County in the 88th percentile nationally for radon potential — higher than 88% of the counties EPA has rated.

Champaign County by the numbers

Champaign County, Ohio is home to about 38,907 people across 428.977 square miles. Population density there runs about 91 people per square mile. By population, Champaign County is the 386th largest of every county sharing its EPA zone — the 64th percentile by population within that zone. Champaign County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Where the national indoor average runs about 1.3 pCi/L, Champaign County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. Some Champaign County homes will test comfortably under the action level despite the county's Zone 1 rating — the only way to know which kind of home you have is an actual test.

Testing and mitigation in Champaign County

For a Champaign 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 Ohio's state radon program

For Champaign County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Champaign 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 Champaign County's figures come from

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