What EPA's radon map says about Chaffee County

EPA's own radon map rates Chaffee County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Rank it against the rest of the country and Chaffee County lands in the 82nd percentile for radon potential.

How Chaffee County compares

About 20,780 people live in Chaffee County, Colorado, spread over 1,013.408 square miles. Population density there runs about 21 people per square mile. Among counties sharing Chaffee County's EPA zone, it outranks 47% of them by population. Chaffee County falls in EPA Radon Region 8, one of 291 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Chaffee County carries a Zone 1 label because its predicted average clears 4 pCi/L outright — three-plus times the 0.4 pCi/L typical outdoors and above the 1.3 pCi/L most homes see. EPA's guidance doesn't change because of a Zone 1 label: test the house. What changes is the reason to not put it off in Chaffee County specifically.

Testing and mitigation in Chaffee County

Mitigation cost doesn't depend on Chaffee 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 Colorado's state radon program

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

More on how this number was built

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