Is San Juan County, UT a radon risk area?

EPA places San Juan County in Zone 2 - Moderate Potential — a predicted county-wide average indoor radon level between 2 and 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Nationally, San Juan County ranks higher in radon potential than 43% of rated counties (the 43rd percentile).

San Juan County by the numbers

About 14,601 people live in San Juan County, Utah, spread over 7,823.687 square miles. That works out to roughly 2 people per square mile. Rank 723 by population within its EPA zone puts San Juan County at the 30th percentile among zone peers. Geologically, San Juan County is grouped into EPA Region 8 alongside 290 other counties that share its rock and soil setting.

Zone vs. an actual test

San Juan County's Zone 2 prediction clears the 1.3 pCi/L national indoor average without reaching EPA's own 4 pCi/L point for recommending a fix. A Zone 2 rating is a moderate county-wide average, not a guarantee about any one house in San Juan County — testing is the only way to know an individual home's actual level.

Next steps for a home in San Juan County

Nothing about San Juan 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 Utah's state radon program

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

More on how this number was built

The methodology guide shows exactly which EPA and Census sources feed San Juan County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.