Is Mason County, MI a radon risk area?

EPA places Mason County in Zone 3 - Low Potential — a predicted county-wide average indoor radon level below 2 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Nationally, Mason County ranks higher in radon potential than 17% of rated counties (the 17th percentile).

Mason County by the numbers

About 29,093 people live in Mason County, Michigan, spread over 494.969 square miles. Population density there runs about 59 people per square mile. Rank 492 by population within its EPA zone puts Mason County at the 52nd percentile among zone peers. Geologically, Mason County is grouped into EPA Region 5 alongside 523 other counties that share its rock and soil setting.

Zone vs. an actual test

Well clear of both the 1.3 pCi/L national indoor average and EPA's 4 pCi/L action level, Mason County's Zone 3 prediction is the low end of the scale. Even at Zone 3, Mason County homes are not guaranteed a low reading — zone is a county-wide average, and EPA recommends testing every home regardless of zone.

Next steps for a home in Mason County

Nothing about Mason County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find Michigan's state radon program

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

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.