Cass County, MN: EPA's radon zone, explained

EPA's own radon map rates Cass County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Cass County sits at the 51st percentile nationally for radon potential — above 51 of every 100 rated counties.

Where Cass County sits nationally

Cass County, Minnesota is home to about 31,442 people across 2,021.484 square miles. Population density there runs about 16 people per square mile. By population, Cass County is the 472nd largest of every county sharing its EPA zone — the 54th percentile by population within that zone. EPA's geology-based Region 5 groups Cass County with 523 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Cass County

Cass 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 county-wide moderate average, like Cass County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Next steps for a home in Cass County

For a Cass County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find Minnesota's state radon program

For Cass County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Cass County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.

Where Cass County's figures come from

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. Whatever zone Cass County carries, the zone explainer covers what it does and doesn't tell you about any one house.