What EPA's radon map says about Terrell County

EPA's own radon map rates Terrell County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Rank it against the rest of the country and Terrell County lands in the 33rd percentile for radon potential.

Terrell County by the numbers

About 718 people live in Terrell County, Texas, spread over 2,357.958 square miles. That works out to roughly 0 people per square mile. Among counties sharing Terrell County's EPA zone, it outranks 0% of them by population. Geologically, Terrell 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

EPA's Zone 2 rating for Terrell County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. Terrell County's Zone 2 rating sits in the middle nationally; EPA's guidance is unchanged by that — test every home regardless of its zone.

Testing and mitigation in Terrell County

Mitigation cost doesn't depend on Terrell County's zone — it depends on the house's foundation. A typical system runs $800–$2,500 (about $1,200 typical), and testing first is what tells you whether that's needed at all.

Find Texas's state radon program

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

Terrell County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.