What EPA's radon map says about Mesa County

EPA places Mesa County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. That puts Mesa County in the 96th percentile nationally for radon potential — higher than 96% of the counties EPA has rated.

How Mesa County compares

About 161,260 people live in Mesa County, Colorado, spread over 3,328.721 square miles. Population density there runs about 48 people per square mile. Among counties sharing Mesa County's EPA zone, it outranks 88% of them by population. Geologically, Mesa 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 Mesa County

Fixing a home becomes an EPA recommendation past 4 pCi/L, and that is precisely the side of the line Mesa County's Zone 1 prediction lands on, well above the roughly 1.3 pCi/L most US homes average. That doesn't mean every Mesa County house tests high — a zone is a county-wide prediction, never a single-home reading — but it's a reason to test sooner rather than let it wait.

If Mesa County tests above the action level

Mitigation cost doesn't depend on Mesa 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

Mesa County's test kit answers today; a Airthings radon monitor keeps answering for Mesa 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 Mesa County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.