Is Brown County, TX a radon risk area?

Brown County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. Nationally that's the 20th percentile for radon potential — Brown County outranks 20% of every county EPA has rated.

Where Brown County sits nationally

About 38,631 people live in Brown County, Texas, spread over 944.452 square miles. That works out to roughly 41 people per square mile. Rank 414 by population within its EPA zone puts Brown County at the 60th percentile among zone peers. EPA's geology-based Region 6 groups Brown County with 502 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

A Zone 3 county like Brown County is predicted closer to the 0.4 pCi/L typical outdoors than to EPA's 4 pCi/L action level. Low doesn't mean zero: EPA's own data shows homes in Zone 3 counties like Brown County testing above the action level often enough that skipping a test isn't the safe assumption.

Next steps for a home in Brown County

Nothing about Brown 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 Texas's state radon program

Brown County's test kit answers today; a Airthings radon monitor keeps answering for Brown County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.

More on how this number was built

Brown County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Brown County carries, the zone explainer covers what it does and doesn't tell you about any one house.