Boundary County, ID radon potential

EPA's own radon map rates Boundary County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Rank it against the rest of the country and Boundary County lands in the 78th percentile for radon potential.

Where Boundary County sits nationally

Boundary County, Idaho is home to about 14,040 people across 1,268.679 square miles. Population density there runs about 11 people per square mile. Within its own EPA zone, Boundary County is bigger by population than 36% of the counties that share it. Geologically, Boundary County is grouped into EPA Region 10 alongside 141 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

Where the national indoor average runs about 1.3 pCi/L, Boundary County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. Some Boundary County homes will test comfortably under the action level despite the county's Zone 1 rating — the only way to know which kind of home you have is an actual test.

If Boundary County tests above the action level

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 Idaho's state radon program

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

Where Boundary County's figures come from

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