Is Stark County, IL a radon risk area?

EPA's own radon map rates Stark County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. That puts Stark County in the 71st percentile nationally for radon potential — higher than 71% of the counties EPA has rated.

How Stark County compares

About 5,272 people live in Stark County, Illinois, spread over 288.106 square miles. Averaged across its land area, Stark County runs about 18 people per square mile. Rank 912 by population within its EPA zone puts Stark County at the 14th percentile among zone peers. EPA's geology-based Region 5 groups Stark County with 523 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

Stark County carries a Zone 1 label because its predicted average clears 4 pCi/L outright — three-plus times the 0.4 pCi/L typical outdoors and above the 1.3 pCi/L most homes see. Some Stark 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.

Next steps for a home in Stark County

Nothing about Stark 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 Illinois's state radon program

Stark County's test kit answers today; a Airthings radon monitor keeps answering for Stark 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

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