What EPA's radon map says about Caldwell County

EPA places Caldwell 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 that's the 22nd percentile for radon potential — Caldwell County outranks 22% of every county EPA has rated.

How Caldwell County compares

About 52,430 people live in Caldwell County, Texas, spread over 544.543 square miles. That works out to roughly 96 people per square mile. Among counties sharing Caldwell County's EPA zone, it outranks 68% of them by population. Geologically, Caldwell County is grouped into EPA Region 6 alongside 502 other counties that share its rock and soil setting.

Zone vs. an actual test

At Zone 3, Caldwell County's predicted county average is under the national indoor average (~1.3 pCi/L) and well below EPA's 4 pCi/L action level — outdoor air nationally runs about 0.4 pCi/L for comparison. A Zone 3 rating means Caldwell 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.

If Caldwell County tests above the action level

Mitigation cost doesn't depend on Caldwell County's zone — it depends on the house's foundation. A typical system runs $800–$2,500 (about $1,200 typical), and testing first is what tells you whether that's needed at all.

Find Texas's state radon program

Caldwell County's test kit answers today; a Airthings radon monitor keeps answering for Caldwell County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Code RADONZONE-10OFF takes 10% off at checkout.

More on how this number was built

Caldwell County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Caldwell County carries, the zone explainer covers what it does and doesn't tell you about any one house.