ADU Regulations in Michigan (MI)
Michigan is rated Moderate for ADU construction with an ADU-friendliness score of 30/100 (Restrictive). Michigan does not have a statewide ADU law — regulations are set entirely by local jurisdictions. Owner must reside on the property. Additional parking may be required. Michigan has no statewide ADU law. ADU policies are set by local municipalities. Ann Arbor and Grand Rapids have led the state with permissive ADU ordinances. Detroit allows ADUs in some zones. The state legislature has considered but not passed ADU reform.
Full ADU Regulations Summary for Michigan
| ADUs Allowed | Yes |
| Statewide ADU Law | No |
| Maximum ADU Size | Set locally |
| Owner Occupancy Required | Yes |
| Parking Required | Yes |
| Minimum Setback | Set locally |
| Permitting Timeline | Varies by jurisdiction |
| Impact Fees | Varies by jurisdiction |
| Long-Term Rental Allowed | Yes |
| Short-Term Rental (Airbnb) Allowed | Yes |
| Ease of Building | Moderate |
ADU Regulations by City in Michigan
ADU rules can vary by city even within the same state. Without a statewide ADU law, Michigan cities set their own rules, and policies can differ significantly. Below are ADU details for 3 cities in Michigan.
Detroit
ADUs allowed in some residential zones. Detroit is expanding ADU permissions to address housing needs.
Ann Arbor
ADUs allowed by right on single-family lots since 2020. Up to 800 sq ft. No owner-occupancy requirement.
Grand Rapids
ADUs permitted in residential zones. Grand Rapids adopted a comprehensive ADU ordinance in 2021.
How Michigan Compares to Other States
Below is a comparison of Michigan with five states that have similar ADU-friendliness scores. This comparison helps illustrate where Michigan stands nationally.
| State | Score | Statewide Law | Parking Req? | Owner Occ? | Ease |
|---|---|---|---|---|---|
| Michigan (MI) | 30 | No | Yes | Yes | Moderate |
| Alabama (AL) | 30 | No | Yes | Yes | Difficult |
| Arkansas (AR) | 30 | No | Yes | Yes | Difficult |
| Delaware (DE) | 30 | No | Yes | Yes | Moderate |
| Georgia (GA) | 30 | No | Yes | Yes | Moderate |
| Idaho (ID) | 30 | No | Yes | Yes | Moderate |
Frequently Asked Questions About ADUs in Michigan
Can I build an ADU in Michigan?
Yes, ADUs are allowed in Michigan. However, Michigan does not have a statewide ADU law, so the specific rules depend on your city or county's zoning code. Some cities are more permissive than others. The ease of building is rated "Moderate" with a friendliness score of 30/100.
Do I need to live on the property to have an ADU in Michigan?
Yes, Michigan generally requires owner occupancy — the property owner must live either in the main house or the ADU. This means you cannot rent out both units simultaneously. Note: individual cities may have their own owner-occupancy rules, so check your local zoning.
How big can an ADU be in Michigan?
Michigan does not set a statewide maximum ADU size — this is determined by your local jurisdiction. Common local limits range from 600 to 1,200 square feet. Check your city's zoning code for the specific maximum.
Do I need extra parking for an ADU in Michigan?
Michigan may require additional off-street parking for ADUs. The specific number of spaces depends on your local jurisdiction. This can be a significant barrier if your lot has limited space for parking.
Can I rent out my ADU in Michigan?
Yes, long-term rentals of ADUs are allowed in Michigan. Short-term rentals (like Airbnb) are also generally permitted, though your city may have separate short-term rental regulations.
How long does it take to get an ADU permit in Michigan?
The permitting timeline in Michigan is: Varies by jurisdiction. Without a statewide mandate, permitting timelines depend entirely on your local jurisdiction's review process. Actual timelines can be affected by plan review backlogs, inspection scheduling, and the complexity of your project. Pre-approved ADU plans, where available, can significantly speed up the process.
Check ADU Rules for Your City
Use our ADU regulations lookup tool to find the specific rules for your city in Michigan, or browse all 50 states to compare ADU regulations across the country. Remember that local rules may be more specific than state-level regulations.