Radon Pros in Michigan

About Radon in Michigan

Last updated: March 2026

Michigan's radon risk is concentrated in the Lower Peninsula, where most of the southeastern and central regions are classified as EPA Zone 1. The glacial soils that cover the Lower Peninsula create ideal conditions for radon gas generation and soil-gas transport into home foundations. The Ann Arbor–Detroit corridor and Grand Rapids metro both report significant radon issues, with Washtenaw, Oakland, Kent, and Ottawa counties consistently showing elevated indoor levels. The Upper Peninsula is mostly Zone 2 with moderate risk. Michigan does not require state-specific radon licensing beyond national NRPP and NRSB certification, which means homeowners must verify contractor credentials independently. In real estate transactions, radon testing is not mandated by state law but is common practice in southeastern Michigan and the Grand Rapids area. Michigan's radon profile is notable for the strong correlation between population density and risk — the Detroit metro and Grand Rapids metro, which contain the majority of the state's population, are both in Zone 1 areas. The Michigan Department of Health and Human Services recommends testing all homes, particularly those with basements, which are the predominant foundation type in the state. Post-mitigation testing is also recommended to verify system effectiveness.