Is Shelby County, IL a radon risk area?

EPA places Shelby County in Zone 2 - Moderate Potential — a predicted county-wide average indoor radon level between 2 and 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Shelby County sits at the 46th percentile nationally for radon potential — above 46 of every 100 rated counties.

How Shelby County compares

About 20,542 people live in Shelby County, Illinois, spread over 758.508 square miles. That works out to roughly 27 people per square mile. Rank 618 by population within its EPA zone puts Shelby County at the 40th percentile among zone peers. EPA's geology-based Region 5 groups Shelby County with 523 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

Call it a middle case: above the 1.3 pCi/L most US homes average, below the 4 pCi/L line EPA uses to recommend mitigation — that's Shelby County's Zone 2 prediction. Nothing about a Zone 2 label lowers the case for testing in Shelby County — EPA recommends it in every zone, moderate included.

Testing and mitigation in Shelby County

Nothing about Shelby 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

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

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