Radon levels in Michigan, county by county
Michigan has a radon problem well above the national average, and it is distributed very unevenly — including across a single metro area.
Roughly 25% of Michigan homes are estimated to have radon above the federal action level of 4.0 pCi/L. Nationally that figure is about 7%. Elevated results have been recorded in all 83 Michigan counties.
Southeast Michigan
| County | Elevated results |
|---|---|
| Livingston | 40% |
| Washtenaw | 38% |
| Oakland | 29% |
| Monroe | 28% |
| Wayne | 17% |
| Macomb | 11% |
The highest counties in the state
| County | Elevated results |
|---|---|
| Branch | 53% |
| Hillsdale | 52% |
| Lenawee | 50% |
| Jackson | 44% |
| Livingston | 40% |
| Washtenaw | 38% |
Why your county percentage is not your answer
These figures describe tests, not houses. A county at 11% still contains homes well above the action level, and a county at 40% contains plenty of homes that test clean. Radon depends on the geology directly under your foundation and on how your particular house moves air — its foundation type, how tight the envelope is, how the heating system runs.
Two houses on the same street routinely test very differently. That is the single most common surprise in this trade, and it is why a neighbour's result is not a substitute for your own.
Free and low-cost test kits
County health departments across Southeast Michigan distribute radon test kits, often free or heavily discounted during January, which is National Radon Action Month. Oakland, Macomb, and Wayne county health divisions have all run kit programmes. A kit is a reasonable way to find out whether you have a problem at all; a professional test with a continuous monitor is what a real estate transaction will want.
Figures above are drawn from the Michigan Department of Environment, Great Lakes, and Energy's published county radon data, which is based on homeowner test results and does not predict any individual home.
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Serving Oakland, Livingston, and Washtenaw counties.