Is Yuma County, CO a radon risk area?

Yuma County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. That puts Yuma County in the 76th percentile nationally for radon potential — higher than 76% of the counties EPA has rated.

Where Yuma County sits nationally

About 10,048 people live in Yuma County, Colorado, spread over 2,364.399 square miles. Averaged across its land area, Yuma County runs about 4 people per square mile. Rank 761 by population within its EPA zone puts Yuma County at the 29th percentile among zone peers. Geologically, Yuma County is grouped into EPA Region 8 alongside 290 other counties that share its rock and soil setting.

What this actually means for a house in Yuma County

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Yuma County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Yuma County will test well under the action level, and EPA's guidance is to test regardless of zone.

Testing and mitigation in Yuma County

Nothing about Yuma County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find Colorado's state radon program

Yuma County's test kit answers today; a Airthings radon monitor keeps answering for Yuma 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 Yuma County's numbers. Whatever zone Yuma County carries, the zone explainer covers what it does and doesn't tell you about any one house.