What EPA's radon map says about Shoshone County

EPA's own radon map rates Shoshone County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally that's the 78th percentile for radon potential — Shoshone County outranks 78% of every county EPA has rated.

How Shoshone County compares

About 14,074 people live in Shoshone County, Idaho, spread over 2,637.425 square miles. Population density there runs about 5 people per square mile. Among counties sharing Shoshone County's EPA zone, it outranks 36% of them by population. Shoshone County falls in EPA Radon Region 10, one of 142 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Shoshone County's predicted average sits above EPA's own action level of 4 pCi/L — the concentration at which EPA recommends fixing a home — versus a national average around 1.3 pCi/L indoors and 0.4 pCi/L outdoors. EPA's guidance doesn't change because of a Zone 1 label: test the house. What changes is the reason to not put it off in Shoshone County specifically.

Testing and mitigation in Shoshone County

Mitigation cost doesn't depend on Shoshone 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 Idaho's state radon program

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

Shoshone County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Shoshone County carries, the zone explainer covers what it does and doesn't tell you about any one house.