Powder River County, MT radon potential

EPA places Powder River County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Nationally, Powder River County ranks higher in radon potential than 67% of rated counties (the 67th percentile).

How Powder River County compares

Powder River County, Montana is home to about 1,734 people across 3,298.196 square miles. Population density there runs about 1 people per square mile. Within its own EPA zone, Powder River County is bigger by population than 2% of the counties that share it. Powder River County falls in EPA Radon Region 8, one of 291 counties nationally EPA assigns to that same geologic province.

Why the zone isn't the answer by itself

Fixing a home becomes an EPA recommendation past 4 pCi/L, and that is precisely the side of the line Powder River County's Zone 1 prediction lands on, well above the roughly 1.3 pCi/L most US homes average. Being in Zone 1 raises the odds Powder River County homes test above the action level, but it does not mean any specific house does — EPA recommends every home be tested, in every zone, because the only way to know is to test.

Next steps for a home in Powder River 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 Powder River County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Powder River County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. Code RADONZONE-10OFF takes 10% off at checkout.

Where Powder River County's figures come from

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