Michigan Radon Levels
9Zone 1 (High)
32Zone 2 (Moderate)
42Zone 3 (Low)
11% of counties in Michigan are classified as EPA Zone 1 (highest radon potential), meaning predicted average indoor radon levels exceed 4 pCi/L — the EPA action level. The EPA recommends that all homes be tested for radon, regardless of zone classification.
| County | EPA Zone | Risk Level |
|---|---|---|
| Alcona County | Zone 2 | Moderate Potential |
| Alger County | Zone 2 | Moderate Potential |
| Allegan County | Zone 3 | Lowest Potential |
| Alpena County | Zone 2 | Moderate Potential |
| Antrim County | Zone 2 | Moderate Potential |
| Arenac County | Zone 3 | Lowest Potential |
| Baraga County | Zone 2 | Moderate Potential |
| Barry County | Zone 2 | Moderate Potential |
| Bay County | Zone 3 | Lowest Potential |
| Benzie County | Zone 3 | Lowest Potential |
| Berrien County | Zone 3 | Lowest Potential |
| Branch County | Zone 1 | Highest Potential |
| Calhoun County | Zone 1 | Highest Potential |
| Cass County | Zone 1 | Highest Potential |
| Charlevoix County | Zone 2 | Moderate Potential |
| Cheboygan County | Zone 3 | Lowest Potential |
| Chippewa County | Zone 3 | Lowest Potential |
| Clare County | Zone 3 | Lowest Potential |
| Clinton County | Zone 2 | Moderate Potential |
| Crawford County | Zone 3 | Lowest Potential |
| Delta County | Zone 3 | Lowest Potential |
| Dickinson County | Zone 2 | Moderate Potential |
| Eaton County | Zone 2 | Moderate Potential |
| Emmet County | Zone 2 | Moderate Potential |
| Genesee County | Zone 2 | Moderate Potential |
| Gladwin County | Zone 3 | Lowest Potential |
| Gogebic County | Zone 2 | Moderate Potential |
| Grand Traverse County | Zone 3 | Lowest Potential |
| Gratiot County | Zone 3 | Lowest Potential |
| Hillsdale County | Zone 1 | Highest Potential |
| Houghton County | Zone 2 | Moderate Potential |
| Huron County | Zone 3 | Lowest Potential |
| Ingham County | Zone 2 | Moderate Potential |
| Ionia County | Zone 2 | Moderate Potential |
| Iosco County | Zone 3 | Lowest Potential |
| Iron County | Zone 2 | Moderate Potential |
| Isabella County | Zone 3 | Lowest Potential |
| Jackson County | Zone 1 | Highest Potential |
| Kalamazoo County | Zone 1 | Highest Potential |
| Kalkaska County | Zone 3 | Lowest Potential |
| Kent County | Zone 2 | Moderate Potential |
| Keweenaw County | Zone 2 | Moderate Potential |
| Lake County | Zone 3 | Lowest Potential |
| Lapeer County | Zone 2 | Moderate Potential |
| Leelanau County | Zone 2 | Moderate Potential |
| Lenawee County | Zone 1 | Highest Potential |
| Livingston County | Zone 2 | Moderate Potential |
| Luce County | Zone 3 | Lowest Potential |
| Mackinac County | Zone 3 | Lowest Potential |
| Macomb County | Zone 3 | Lowest Potential |
| Manistee County | Zone 3 | Lowest Potential |
| Marquette County | Zone 2 | Moderate Potential |
| Mason County | Zone 3 | Lowest Potential |
| Mecosta County | Zone 3 | Lowest Potential |
| Menominee County | Zone 2 | Moderate Potential |
| Midland County | Zone 3 | Lowest Potential |
| Missaukee County | Zone 3 | Lowest Potential |
| Monroe County | Zone 2 | Moderate Potential |
| Montcalm County | Zone 2 | Moderate Potential |
| Montmorency County | Zone 2 | Moderate Potential |
| Muskegon County | Zone 3 | Lowest Potential |
| Newaygo County | Zone 3 | Lowest Potential |
| Oakland County | Zone 2 | Moderate Potential |
| Oceana County | Zone 3 | Lowest Potential |
| Ogemaw County | Zone 3 | Lowest Potential |
| Ontonagon County | Zone 3 | Lowest Potential |
| Osceola County | Zone 3 | Lowest Potential |
| Oscoda County | Zone 3 | Lowest Potential |
| Otsego County | Zone 2 | Moderate Potential |
| Ottawa County | Zone 3 | Lowest Potential |
| Presque Isle County | Zone 2 | Moderate Potential |
| Roscommon County | Zone 3 | Lowest Potential |
| Saginaw County | Zone 3 | Lowest Potential |
| St. Clair County | Zone 3 | Lowest Potential |
| St. Joseph County | Zone 1 | Highest Potential |
| Sanilac County | Zone 2 | Moderate Potential |
| Schoolcraft County | Zone 3 | Lowest Potential |
| Shiawassee County | Zone 2 | Moderate Potential |
| Tuscola County | Zone 3 | Lowest Potential |
| Van Buren County | Zone 3 | Lowest Potential |
| Washtenaw County | Zone 1 | Highest Potential |
| Wayne County | Zone 3 | Lowest Potential |
| Wexford County | Zone 3 | Lowest Potential |