Wibaux County, MT: EPA's radon zone, explained

Wibaux County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Nationally, Wibaux County ranks higher in radon potential than 66% of rated counties (the 66th percentile).

How Wibaux County compares

Wibaux County, Montana is home to about 911 people across 889.571 square miles. Averaged across its land area, Wibaux County runs about 1 people per square mile. By population, Wibaux County is the 1062nd largest of every county sharing its EPA zone — the 0th percentile by population within that zone. Geologically, Wibaux 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

Fixing a home becomes an EPA recommendation past 4 pCi/L, and that is precisely the side of the line Wibaux 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 Wibaux 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.

If Wibaux County tests above the action level

For a Wibaux County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find Montana's state radon program

For Wibaux County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Wibaux 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 Wibaux County's figures come from

The methodology guide shows exactly which EPA and Census sources feed Wibaux County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.