What EPA's radon map says about Treasure County

Treasure County is mapped as Zone 2 - Moderate Potential by EPA — meaning the county-wide average indoor level is predicted between 2 and 4 pCi/L. That puts Treasure County in the 33rd percentile nationally for radon potential — higher than 33% of the counties EPA has rated.

Treasure County by the numbers

About 739 people live in Treasure County, Montana, spread over 977.801 square miles. Averaged across its land area, Treasure County runs about 1 people per square mile. Among counties sharing Treasure County's EPA zone, it outranks 0% of them by population. Geologically, Treasure County is grouped into EPA Region 8 alongside 290 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

EPA's Zone 2 rating for Treasure County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. Nothing about a Zone 2 label lowers the case for testing in Treasure County — EPA recommends it in every zone, moderate included.

Next steps for a home in Treasure County

Mitigation cost doesn't depend on Treasure 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 Montana's state radon program

Treasure County's test kit answers today; a Airthings radon monitor keeps answering for Treasure 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

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.