What EPA's radon map says about Carbon County

Carbon County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Carbon County sits at the 82nd percentile nationally for radon potential — above 82 of every 100 rated counties.

Where Carbon County sits nationally

About 20,613 people live in Carbon County, Utah, spread over 1,479.343 square miles. Averaged across its land area, Carbon County runs about 14 people per square mile. Among counties sharing Carbon County's EPA zone, it outranks 47% of them by population. Carbon County falls in EPA Radon Region 8, one of 291 counties nationally EPA assigns to that same geologic province.

Why the zone isn't the answer by itself

Where the national indoor average runs about 1.3 pCi/L, Carbon County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. That doesn't mean every Carbon 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.

Testing and mitigation in Carbon County

Mitigation cost doesn't depend on Carbon 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 Utah's state radon program

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

More on how this number was built

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