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

EPA's own radon map rates Zapata 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 Zapata County lands in the 9th percentile for radon potential.

Where Zapata County sits nationally

Zapata County, Texas is home to about 13,819 people across 998.415 square miles. Population density there runs about 14 people per square mile. By population, Zapata County is the 736th largest of every county sharing its EPA zone — the 29th percentile by population within that zone. EPA's geology-based Region 6 groups Zapata County with 502 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Zapata County's Zone 3 prediction undercuts the roughly 1.3 pCi/L most US homes average, nowhere near EPA's 4 pCi/L threshold for recommending mitigation. A Zone 3 rating means Zapata 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 Zapata County

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

The methodology guide shows exactly which EPA and Census sources feed Zapata County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.