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

EPA's own radon map rates Mills County zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. That puts Mills County in the 2nd percentile nationally for radon potential — higher than 2% of the counties EPA has rated.

Where Mills County sits nationally

Mills County, Texas is home to about 4,563 people across 748.225 square miles. Population density there runs about 6 people per square mile. By population, Mills County is the 955th largest of every county sharing its EPA zone — the 7th percentile by population within that zone. EPA's geology-based Region 6 groups Mills County with 502 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Mills County

Mills 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. A Zone 3 label describes Mills County's average, not any one basement or slab in it — testing is still the only way an individual homeowner actually finds out.

Testing and mitigation in Mills County

For a Mills 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 Mills County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Mills 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 Mills County's figures come from

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. Whatever zone Mills County carries, the zone explainer covers what it does and doesn't tell you about any one house.