Dallam County, TX: EPA's radon zone, explained

Dallam County is mapped as Zone 2 - Moderate Potential by EPA — meaning the county-wide average indoor level is predicted between 2 and 4 pCi/L. Nationally that's the 38th percentile for radon potential — Dallam County outranks 38% of every county EPA has rated.

Dallam County by the numbers

Dallam County, Texas is home to about 7,526 people across 1,503.353 square miles. Averaged across its land area, Dallam County runs about 5 people per square mile. By population, Dallam County is the 884th largest of every county sharing its EPA zone — the 14th percentile by population within that zone. EPA's geology-based Region 6 groups Dallam County with 502 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

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

If Dallam County tests above the action level

For a Dallam County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find Texas's state radon program

For Dallam County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Dallam County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

Where Dallam County's figures come from

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