What EPA's radon map says about Campbell County

Campbell County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Campbell County sits at the 90th percentile nationally for radon potential — above 90 of every 100 rated counties.

Campbell County by the numbers

About 47,946 people live in Campbell County, Wyoming, spread over 4,802.065 square miles. Averaged across its land area, Campbell County runs about 10 people per square mile. Among counties sharing Campbell County's EPA zone, it outranks 69% of them by population. EPA's geology-based Region 8 groups Campbell County with 290 other counties nationally sharing its underlying rock and soil profile.

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 Campbell 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 Campbell 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 Campbell County

Mitigation cost doesn't depend on Campbell 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 Wyoming's state radon program

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

Campbell County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.