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

EPA places Travis County in Zone 3 - Low Potential — a predicted county-wide average indoor radon level below 2 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Nationally, Travis County ranks higher in radon potential than 32% of rated counties (the 32nd percentile).

Where Travis County sits nationally

Travis County, Texas is home to about 1,363,767 people across 994.329 square miles. Population density there runs about 1,372 people per square mile. By population, Travis County is the 21st largest of every county sharing its EPA zone — the 98th percentile by population within that zone. EPA's geology-based Region 6 groups Travis County with 502 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

Travis 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. Don't read Zone 3 as a pass for Travis County — EPA's guidance to test every home makes no exception for counties predicted low.

Testing and mitigation in Travis County

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

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