What EPA's radon map says about Brazoria County

EPA places Brazoria County in Zone 3 - Low Potential — a predicted county-wide average indoor radon level below 2 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Rank it against the rest of the country and Brazoria County lands in the 31st percentile for radon potential.

Where Brazoria County sits nationally

About 413,224 people live in Brazoria County, Texas, spread over 1,363.318 square miles. Population density there runs about 303 people per square mile. Among counties sharing Brazoria County's EPA zone, it outranks 94% of them by population. Geologically, Brazoria County is grouped into EPA Region 6 alongside 502 other counties that share its rock and soil setting.

Zone vs. an actual test

A Zone 3 county like Brazoria County is predicted closer to the 0.4 pCi/L typical outdoors than to EPA's 4 pCi/L action level. A Zone 3 rating means Brazoria County's county-wide average is predicted low, but EPA is explicit that a meaningful share of homes in low-potential zones still test above the action level — a low zone is not a reason to skip testing.

Testing and mitigation in Brazoria County

Mitigation cost doesn't depend on Brazoria 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

Brazoria County's test kit answers today; a Airthings radon monitor keeps answering for Brazoria 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

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