Is Bexar County, TX a radon risk area?

EPA's own radon map rates Bexar County zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. That puts Bexar County in the 33rd percentile nationally for radon potential — higher than 33% of the counties EPA has rated.

How Bexar County compares

About 2,127,737 people live in Bexar County, Texas, spread over 1,240.419 square miles. Population density there runs about 1,715 people per square mile. Rank 10 by population within its EPA zone puts Bexar County at the 99th percentile among zone peers. Bexar County falls in EPA Radon Region 6, one of 503 counties nationally EPA assigns to that same geologic province.

Why the zone isn't the answer by itself

Well clear of both the 1.3 pCi/L national indoor average and EPA's 4 pCi/L action level, Bexar County's Zone 3 prediction is the low end of the scale. Even at Zone 3, Bexar County homes are not guaranteed a low reading — zone is a county-wide average, and EPA recommends testing every home regardless of zone.

If Bexar County tests above the action level

Nothing about Bexar 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

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

More on how this number was built

The methodology guide shows exactly which EPA and Census sources feed Bexar County's numbers. Whatever zone Bexar County carries, the zone explainer covers what it does and doesn't tell you about any one house.