What EPA's radon map says about Mahnomen County

EPA's own radon map rates Mahnomen County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Rank it against the rest of the country and Mahnomen County lands in the 71st percentile for radon potential.

How Mahnomen County compares

About 5,296 people live in Mahnomen County, Minnesota, spread over 557.867 square miles. That works out to roughly 9 people per square mile. Among counties sharing Mahnomen County's EPA zone, it outranks 14% of them by population. EPA's geology-based Region 5 groups Mahnomen County with 523 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Mahnomen County carries a Zone 1 label because its predicted average clears 4 pCi/L outright — three-plus times the 0.4 pCi/L typical outdoors and above the 1.3 pCi/L most homes see. Some Mahnomen County homes will test comfortably under the action level despite the county's Zone 1 rating — the only way to know which kind of home you have is an actual test.

Testing and mitigation in Mahnomen County

Mitigation cost doesn't depend on Mahnomen 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 Minnesota's state radon program

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

Mahnomen County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.