Is Comal County, TX a radon risk area?

EPA's own radon map rates Comal County zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. Rank it against the rest of the country and Comal County lands in the 29th percentile for radon potential.

Where Comal County sits nationally

About 201,628 people live in Comal County, Texas, spread over 559.537 square miles. Averaged across its land area, Comal County runs about 360 people per square mile. Rank 131 by population within its EPA zone puts Comal County at the 87th percentile among zone peers. Geologically, Comal County is grouped into EPA Region 6 alongside 502 other counties that share its rock and soil setting.

What this actually means for a house in Comal County

Well clear of both the 1.3 pCi/L national indoor average and EPA's 4 pCi/L action level, Comal County's Zone 3 prediction is the low end of the scale. A Zone 3 rating means Comal 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 Comal County

Nothing about Comal 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

Comal County's test kit answers today; a Airthings radon monitor keeps answering for Comal 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 Comal County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.