What EPA's radon map says about Bay County

EPA's own radon map rates Bay County zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. Bay County sits at the 26th percentile nationally for radon potential — above 26 of every 100 rated counties.

How Bay County compares

About 102,651 people live in Bay County, Michigan, spread over 442.41 square miles. Population density there runs about 232 people per square mile. Among counties sharing Bay County's EPA zone, it outranks 79% of them by population. Bay County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Bay County's predicted average sits below the national indoor average of about 1.3 pCi/L, well under EPA's 4 pCi/L action level. Even at Zone 3, Bay County homes are not guaranteed a low reading — zone is a county-wide average, and EPA recommends testing every home regardless of zone.

Testing and mitigation in Bay County

Mitigation cost doesn't depend on Bay 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

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

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 Bay County carries, the zone explainer covers what it does and doesn't tell you about any one house.