What EPA's radon map says about Brewster County

EPA places Brewster County in Zone 2 - Moderate Potential — a predicted county-wide average indoor radon level between 2 and 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Brewster County sits at the 39th percentile nationally for radon potential — above 39 of every 100 rated counties.

Where Brewster County sits nationally

About 9,508 people live in Brewster County, Texas, spread over 6,183.763 square miles. Averaged across its land area, Brewster County runs about 2 people per square mile. Among counties sharing Brewster County's EPA zone, it outranks 20% of them by population. EPA's geology-based Region 6 groups Brewster County with 502 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Brewster 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 Brewster County address — a moderate county average still leaves individual homes to test either side of it.

Next steps for a home in Brewster County

Mitigation cost doesn't depend on Brewster 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 Texas's state radon program

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

More on how this number was built

The methodology guide shows exactly which EPA and Census sources feed Brewster County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.