Is Knox County, TX a radon risk area?

EPA's own radon map rates Knox 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 Knox County lands in the 2nd percentile for radon potential.

How Knox County compares

About 3,255 people live in Knox County, Texas, spread over 850.621 square miles. Averaged across its land area, Knox County runs about 4 people per square mile. Rank 973 by population within its EPA zone puts Knox County at the 6th percentile among zone peers. Geologically, Knox County is grouped into EPA Region 6 alongside 502 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

Knox 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. Even at Zone 3, Knox County homes are not guaranteed a low reading — zone is a county-wide average, and EPA recommends testing every home regardless of zone.

If Knox County tests above the action level

Nothing about Knox 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

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

Knox County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Knox County carries, the zone explainer covers what it does and doesn't tell you about any one house.