State radon data hub
Michigan radon levels, county by county
83 Michigan counties have published radon test data. Ranked worst-first below — the median county sees 16.6% of home tests reach the EPA action level of 4 pCi/L. Deep-dive pages (data + geology + housing stock) exist for 7 counties so far; more ship as coverage expands.
Costs, licensing, and how to read a quote: the Michigan mitigation cost guide. Instant county lookup: radon by ZIP.
| # | County | % tests ≥ 4 pCi/L | Tests (10-yr) | EPA zone |
|---|---|---|---|---|
| 1 | Lenawee | 56.7% | 1,349 | 1 |
| 2 | Branch | 55.4% | 586 | 1 |
| 3 | Hillsdale | 54.8% | 1,177 | 1 |
| 4 | Jackson | 49.7% | 1,989 | 1 |
| 5 | Livingston | 43.1% | 3,306 | 2 |
| 6 | Washtenaw | 41.3% | 5,668 | 1 |
| 7 | Dickinson | 39.3% | 446 | 2 |
| 8 | Clinton | 38.5% | 1,466 | 2 |
| 9 | Otsego | 38.2% | 598 | 2 |
| 10 | Ionia | 36.8% | 899 | 2 |
| 11 | Calhoun | 36.4% | 1,235 | 1 |
| 12 | Iron | 36.2% | 172 | 2 |
| 13 | Tuscola | 35.5% | 267 | 3 |
| 14 | Eaton | 34.4% | 2,180 | 2 |
| 15 | St. Joseph | 34.1% | 652 | 1 |
| 16 | Lapeer | 33.4% | 479 | 2 |
| 17 | Kalamazoo | 33.3% | 3,261 | 1 |
| 18 | Shiawassee | 31.6% | 1,021 | 2 |
| 19 | Barry | 30.7% | 1,078 | 2 |
| 20 | Cass | 30.4% | 449 | 1 |
| 21 | Monroe | 30.4% | 1,065 | 2 |
| 22 | Oakland | 28.8% | 12,288 | 2 |
| 23 | Huron | 26.5% | 196 | 3 |
| 24 | Ingham | 24.9% | 2,399 | 2 |
| 25 | Berrien | 24.2% | 1,030 | 3 |
| 26 | Montcalm | 23.6% | 407 | 2 |
| 27 | Marquette | 23.4% | 686 | 2 |
| 28 | Presque Isle | 22.8% | 321 | 2 |
| 29 | Keweenaw | 22.7% | 24 | 2 |
| 30 | Genesee | 21.9% | 1,355 | 2 |
| 31 | Mecosta | 21.7% | 408 | 3 |
| 32 | Delta | 21.5% | 417 | 3 |
| 33 | Alcona | 20.5% | 128 | 2 |
| 34 | Mackinac | 19.8% | 66 | 3 |
| 35 | Oscoda | 18.5% | 40 | 3 |
| 36 | Allegan | 18.4% | 592 | 3 |
| 37 | Van Buren | 18% | 335 | 3 |
| 38 | Wayne | 17.5% | 4,582 | 3 |
| 39 | Saginaw | 17% | 2,213 | 3 |
| 40 | Gratiot | 16.8% | 327 | 3 |
| 41 | Ottawa | 16.8% | 1,957 | 3 |
| 42 | Sanilac | 16.6% | 264 | 2 |
| 43 | Kent | 16.5% | 6,257 | 2 |
| 44 | Manistee | 16.5% | 286 | 3 |
| 45 | Alger | 16.4% | 118 | 2 |
| 46 | Isabella | 16.4% | 568 | 3 |
| 47 | Gladwin | 15.4% | 187 | 3 |
| 48 | Emmet | 15.2% | 528 | 2 |
| 49 | Schoolcraft | 15.2% | 52 | 3 |
| 50 | Ogemaw | 15% | 81 | 3 |
| 51 | Lake | 14.9% | 76 | 3 |
| 52 | Missaukee | 14.9% | 237 | 3 |
| 53 | Montmorency | 14.7% | 156 | 2 |
| 54 | Clare | 14.1% | 154 | 3 |
| 55 | St. Clair | 13.7% | 515 | 3 |
| 56 | Macomb | 13.4% | 4,659 | 3 |
| 57 | Alpena | 13.3% | 727 | 2 |
| 58 | Gogebic | 12.9% | 127 | 2 |
| 59 | Kalkaska | 12.7% | 157 | 3 |
| 60 | Roscommon | 12.7% | 132 | 3 |
| 61 | Antrim | 12% | 232 | 2 |
| 62 | Menominee | 11.7% | 77 | 2 |
| 63 | Chippewa | 11.6% | 222 | 3 |
| 64 | Grand Traverse | 11.5% | 932 | 3 |
| 65 | Ontonagon | 11.4% | 87 | 3 |
| 66 | Baraga | 11% | 116 | 2 |
| 67 | Houghton | 10.8% | 680 | 2 |
| 68 | Osceola | 10.6% | 189 | 3 |
| 69 | Charlevoix | 9.8% | 368 | 2 |
| 70 | Wexford | 9.7% | 446 | 3 |
| 71 | Arenac | 8.9% | 62 | 3 |
| 72 | Benzie | 8.7% | 222 | 3 |
| 73 | Bay | 8.5% | 501 | 3 |
| 74 | Cheboygan | 8% | 349 | 3 |
| 75 | Newaygo | 7.9% | 331 | 3 |
| 76 | Iosco | 7.7% | 107 | 3 |
| 77 | Leelanau | 7.7% | 387 | 2 |
| 78 | Mason | 6.3% | 348 | 3 |
| 79 | Crawford | 6.2% | 143 | 3 |
| 80 | Oceana | 5.9% | 270 | 3 |
| 81 | Midland | 5.3% | 1,430 | 3 |
| 82 | Luce | 4.2% | 19 | 3 |
| 83 | Muskegon | 3.2% | 536 | 3 |
Source: CDC EPHT (labs), 2008–2017; county rank by share of tests at or above 4 pCi/L (counties with too few reported tests are excluded — absence of data is not absence of radon). Zones: EPA Map of Radon Zones. Full sourcing on the methodology page.