Keweenaw County, MI: EPA's radon zone, explained

EPA places Keweenaw County in Zone 2 - Moderate Potential — a predicted county-wide average indoor radon level between 2 and 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Keweenaw County sits at the 34th percentile nationally for radon potential — above 34 of every 100 rated counties.

How Keweenaw County compares

Keweenaw County, Michigan is home to about 2,161 people across 540.112 square miles. That works out to roughly 4 people per square mile. By population, Keweenaw County is the 999th largest of every county sharing its EPA zone — the 3rd percentile by population within that zone. Keweenaw County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Call it a middle case: above the 1.3 pCi/L most US homes average, below the 4 pCi/L line EPA uses to recommend mitigation — that's Keweenaw County's Zone 2 prediction. A Zone 2 rating is a moderate county-wide average, not a guarantee about any one house in Keweenaw County — testing is the only way to know an individual home's actual level.

Testing and mitigation in Keweenaw County

For a Keweenaw 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 Michigan's state radon program

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

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