Is Matagorda County, TX a radon risk area?

EPA places Matagorda 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. That puts Matagorda County in the 19th percentile nationally for radon potential — higher than 19% of the counties EPA has rated.

Where Matagorda County sits nationally

About 36,391 people live in Matagorda County, Texas, spread over 1,093.131 square miles. That works out to roughly 33 people per square mile. Rank 433 by population within its EPA zone puts Matagorda County at the 58th percentile among zone peers. EPA's geology-based Region 6 groups Matagorda County with 502 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Matagorda County's predicted average sits below the national indoor average of about 1.3 pCi/L, well under EPA's 4 pCi/L action level. Low doesn't mean zero: EPA's own data shows homes in Zone 3 counties like Matagorda County testing above the action level often enough that skipping a test isn't the safe assumption.

If Matagorda County tests above the action level

Nothing about Matagorda 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

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

Matagorda County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.