Teton County, MT radon potential
EPA's own radon map rates Teton County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally, Teton County ranks higher in radon potential than 72% of rated counties (the 72nd percentile).
Where Teton County sits nationally
Teton County, Montana is home to about 6,444 people across 2,271.616 square miles. Population density there runs about 3 people per square mile. Within its own EPA zone, Teton County is bigger by population than 19% of the counties that share it. Geologically, Teton 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
Teton County carries a Zone 1 label because its predicted average clears 4 pCi/L outright — three-plus times the 0.4 pCi/L typical outdoors and above the 1.3 pCi/L most homes see. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Teton County will test well under the action level, and EPA's guidance is to test regardless of zone.
Next steps for a home in Teton County
A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.
Find Montana's state radon program
For Teton County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Teton County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.
Where Teton County's figures come from
Teton County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.