Is Monroe County, MI a radon risk area?

Monroe 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. Monroe County sits at the 61st percentile nationally for radon potential — above 61 of every 100 rated counties.

How Monroe County compares

About 156,045 people live in Monroe County, Michigan, spread over 549.358 square miles. Averaged across its land area, Monroe County runs about 284 people per square mile. Rank 148 by population within its EPA zone puts Monroe County at the 86th percentile among zone peers. EPA's geology-based Region 5 groups Monroe County with 523 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

EPA's Zone 2 rating for Monroe County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. Nothing about a Zone 2 label lowers the case for testing in Monroe County — EPA recommends it in every zone, moderate included.

If Monroe County tests above the action level

Nothing about Monroe 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

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

Monroe County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Monroe County carries, the zone explainer covers what it does and doesn't tell you about any one house.