Is Nobles County, MN a radon risk area?

Nobles County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Nationally, Nobles County ranks higher in radon potential than 83% of rated counties (the 83rd percentile).

How Nobles County compares

About 21,969 people live in Nobles County, Minnesota, spread over 715.117 square miles. That works out to roughly 31 people per square mile. Rank 542 by population within its EPA zone puts Nobles County at the 49th percentile among zone peers. Geologically, Nobles 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 Nobles County

Nobles 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. That doesn't mean every Nobles County house tests high — a zone is a county-wide prediction, never a single-home reading — but it's a reason to test sooner rather than let it wait.

Testing and mitigation in Nobles County

Nothing about Nobles 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 Minnesota's state radon program

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

The methodology guide shows exactly which EPA and Census sources feed Nobles County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.