What EPA's radon map says about Jasper County

Jasper County is mapped as Zone 2 - Moderate Potential by EPA — meaning the county-wide average indoor level is predicted between 2 and 4 pCi/L. Rank it against the rest of the country and Jasper County lands in the 39th percentile for radon potential.

Where Jasper County sits nationally

About 9,092 people live in Jasper County, Illinois, spread over 494.614 square miles. That works out to roughly 18 people per square mile. Among counties sharing Jasper County's EPA zone, it outranks 19% of them by population. Geologically, Jasper 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 Jasper County

Jasper County's predicted average falls between EPA's 4 pCi/L action level and the national indoor average of about 1.3 pCi/L (outdoor air runs roughly 0.4 pCi/L). A Zone 2 rating is a moderate county-wide average, not a guarantee about any one house in Jasper County — testing is the only way to know an individual home's actual level.

If Jasper County tests above the action level

Mitigation cost doesn't depend on Jasper 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

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

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.