Is DeKalb County, IN a radon risk area?

DeKalb County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Nationally, DeKalb County ranks higher in radon potential than 89% of rated counties (the 89th percentile).

DeKalb County by the numbers

About 44,330 people live in DeKalb County, Indiana, spread over 362.834 square miles. That works out to roughly 122 people per square mile. Rank 353 by population within its EPA zone puts DeKalb County at the 67th percentile among zone peers. Geologically, DeKalb 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 DeKalb County

Where the national indoor average runs about 1.3 pCi/L, DeKalb County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. 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 DeKalb County specifically.

Testing and mitigation in DeKalb County

Nothing about DeKalb 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 Indiana's state radon program

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

More on how this number was built

DeKalb 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.