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

EPA places Brown County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. That puts Brown County in the 84th percentile nationally for radon potential — higher than 84% of the counties EPA has rated.

Brown County by the numbers

Brown County, Minnesota is home to about 25,710 people across 611.109 square miles. That works out to roughly 42 people per square mile. By population, Brown County is the 511th largest of every county sharing its EPA zone — the 52nd percentile by population within that zone. Geologically, Brown 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 Brown County

Fixing a home becomes an EPA recommendation past 4 pCi/L, and that is precisely the side of the line Brown County's Zone 1 prediction lands on, well above the roughly 1.3 pCi/L most US homes average. Being in Zone 1 raises the odds Brown County homes test above the action level, but it does not mean any specific house does — EPA recommends every home be tested, in every zone, because the only way to know is to test.

Next steps for a home in Brown County

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

Where Brown 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 Brown County carries, the zone explainer covers what it does and doesn't tell you about any one house.