Is Cass County, TX a radon risk area?

EPA's own radon map rates Cass County zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. That puts Cass County in the 17th percentile nationally for radon potential — higher than 17% of the counties EPA has rated.

Cass County by the numbers

About 28,622 people live in Cass County, Texas, spread over 936.947 square miles. Population density there runs about 31 people per square mile. Rank 498 by population within its EPA zone puts Cass County at the 52nd percentile among zone peers. EPA's geology-based Region 6 groups Cass County with 502 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Cass 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 Cass County testing above the action level often enough that skipping a test isn't the safe assumption.

Testing and mitigation in Cass County

Nothing about Cass 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

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

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