Sanpete County, UT: EPA's radon zone, explained

EPA places Sanpete 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. Sanpete County sits at the 85th percentile nationally for radon potential — above 85 of every 100 rated counties.

How Sanpete County compares

Sanpete County, Utah is home to about 30,732 people across 1,589.816 square miles. That works out to roughly 19 people per square mile. By population, Sanpete County is the 461st largest of every county sharing its EPA zone — the 57th percentile by population within that zone. Sanpete County falls in EPA Radon Region 8, one of 291 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Sanpete County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. That doesn't mean every Sanpete 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.

Next steps for a home in Sanpete County

For a Sanpete County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find Utah's state radon program

For Sanpete County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Sanpete County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. Code RADONZONE-10OFF takes 10% off at checkout.

Where Sanpete County's figures come from

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