What EPA's radon map says about Marquette County

Marquette County is mapped as Zone 2 - Moderate Potential by EPA — meaning the county-wide average indoor level is predicted between 2 and 4 pCi/L. That puts Marquette County in the 57th percentile nationally for radon potential — higher than 57% of the counties EPA has rated.

Where Marquette County sits nationally

About 67,979 people live in Marquette County, Michigan, spread over 1,809.071 square miles. That works out to roughly 38 people per square mile. Among counties sharing Marquette County's EPA zone, it outranks 74% of them by population. EPA's geology-based Region 5 groups Marquette County with 523 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Marquette County

Marquette County's predicted average falls between EPA's 4 pCi/L action level and the national indoor average of about 1.3 pCi/L (outdoor air runs roughly 0.4 pCi/L). A county-wide moderate average, like Marquette County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Testing and mitigation in Marquette County

Mitigation cost doesn't depend on Marquette 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 Michigan's state radon program

Marquette County's test kit answers today; a Airthings radon monitor keeps answering for Marquette County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Code RADONZONE-10OFF takes 10% off at checkout.

More on how this number was built

The methodology guide shows exactly which EPA and Census sources feed Marquette County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.