Hays County, TX radon potential

EPA places Hays 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. Hays County sits at the 30th percentile nationally for radon potential — above 30 of every 100 rated counties.

Where Hays County sits nationally

Hays County, Texas is home to about 292,029 people across 676.863 square miles. Population density there runs about 431 people per square mile. Within its own EPA zone, Hays County is bigger by population than 91% of the counties that share it. Geologically, Hays County is grouped into EPA Region 6 alongside 502 other counties that share its rock and soil setting.

Zone vs. an actual test

A Zone 3 county like Hays County is predicted closer to the 0.4 pCi/L typical outdoors than to EPA's 4 pCi/L action level. Don't read Zone 3 as a pass for Hays County — EPA's guidance to test every home makes no exception for counties predicted low.

Next steps for a home in Hays County

A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.

Find Texas's state radon program

For Hays County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Hays 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 Hays 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 Hays County carries, the zone explainer covers what it does and doesn't tell you about any one house.