What EPA's radon map says about Scott County

Scott County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Rank it against the rest of the country and Scott County lands in the 70th percentile for radon potential.

How Scott County compares

About 4,880 people live in Scott County, Illinois, spread over 250.79 square miles. Population density there runs about 19 people per square mile. Among counties sharing Scott County's EPA zone, it outranks 13% of them by population. Scott County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Scott County's predicted average sits above EPA's own action level of 4 pCi/L — the concentration at which EPA recommends fixing a home — versus a national average around 1.3 pCi/L indoors and 0.4 pCi/L outdoors. 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 Scott County specifically.

Testing and mitigation in Scott County

Mitigation cost doesn't depend on Scott County's zone — it depends on the house's foundation. A typical system runs $800–$2,500 (about $1,200 typical), and testing first is what tells you whether that's needed at all.

Find Illinois's state radon program

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

More on how this number was built

Scott County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.