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

Brown County is mapped as Zone 2 - Moderate Potential by EPA — meaning the county-wide average indoor level is predicted between 2 and 4 pCi/L. That puts Brown County in the 43rd percentile nationally for radon potential — higher than 43% of the counties EPA has rated.

Brown County by the numbers

Brown County, Indiana is home to about 15,650 people across 312 square miles. That works out to roughly 50 people per square mile. By population, Brown County is the 703rd largest of every county sharing its EPA zone — the 32nd 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.

Zone vs. an actual test

Brown 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). Middle-of-the-pack doesn't mean risk-free for any one Brown County address — a moderate county average still leaves individual homes to test either side of it.

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 Indiana'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. RADONZONE-10OFF at checkout knocks 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. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.