Is Harrison County, TX a radon risk area?

EPA's own radon map rates Harrison County zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. Nationally, Harrison County ranks higher in radon potential than 24% of rated counties (the 24th percentile).

How Harrison County compares

About 71,370 people live in Harrison County, Texas, spread over 900.064 square miles. That works out to roughly 79 people per square mile. Rank 267 by population within its EPA zone puts Harrison County at the 74th percentile among zone peers. Geologically, Harrison 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 Harrison County

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

Nothing about Harrison 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

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

Harrison 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.