Is Ottawa County, MI a radon risk area?

Ottawa County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. Nationally, Ottawa County ranks higher in radon potential than 30% of rated counties (the 30th percentile).

How Ottawa County compares

About 306,235 people live in Ottawa County, Michigan, spread over 563.52 square miles. Population density there runs about 543 people per square mile. Rank 85 by population within its EPA zone puts Ottawa County at the 92nd percentile among zone peers. Ottawa County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.

What this actually means for a house in Ottawa County

Well clear of both the 1.3 pCi/L national indoor average and EPA's 4 pCi/L action level, Ottawa County's Zone 3 prediction is the low end of the scale. A Zone 3 label describes Ottawa County's average, not any one basement or slab in it — testing is still the only way an individual homeowner actually finds out.

If Ottawa County tests above the action level

Nothing about Ottawa 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

Ottawa County's test kit answers today; a Airthings radon monitor keeps answering for Ottawa 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. Whatever zone Ottawa County carries, the zone explainer covers what it does and doesn't tell you about any one house.