ADU Rules in Detroit, MI (2026)
ADU rules, permit requirements, size limits, and fees for Detroit, MI. Source-cited from official municipal code.
Whether ADUs are allowed in Detroit, MI has not been confirmed — see the official source before proceeding.
Whether Detroit, MI permits accessory dwelling units (ADUs) has not been confirmed from an official source. ADUs — also called granny flats, in-law units, or secondary suites — are secondary housing units on a single-family or multifamily lot. Contact the local building department at (313) 224-2733 to verify current ADU rules before proceeding, as regulations may have changed since this data was last reviewed.
ADU Size Limits
ADU Size Limits in Detroit: Detached ADU: size varies by zoning — see official source (max height: varies — see official source). Attached ADU: size varies by zoning — see official source.
| Type | Max Size | Max Height |
|---|---|---|
| Detached ADU | See official source | See official source |
| Attached ADU | See official source | See official source |
Permit Fees
ADU Permit Fees in Detroit: Plan check fee: Varies. Building permit fee: Varies. Impact fees: None. School fees: None or N/A. Total estimated permit cost: Varies.
| Fee Type | Amount |
|---|---|
| Plan Check | $150-$800 |
| Building Permit | Based on construction value — typically $800-$3,500 |
| Impact Fees | None |
| School Fees | None |
| Total Estimate | See official source |
Permit Timeline
Detroit ADU Permit Timeline: Permit timeline has not been confirmed — contact the department for current processing times. Apply through the local building department online permit portal. Phone: (313) 224-2733.
Setback Requirements
ADU Setback Requirements in Detroit: Front setback: follows zone standard. Side setback: no minimum. Rear setback: no minimum.
Parking Requirements
Parking Requirements: Parking requirements have not been confirmed — see official source.
Restrictions & Requirements
- ADU must comply with Detroit Building Code habitability standards
- Detached ADU limited to rear yard — not permitted in front or side yards
- Structure must meet minimum 7 ft ceiling height for habitable space
- All utilities must be properly connected — no unpermitted electrical or plumbing
- Historic district overlay (Woodbridge, Indian Village, Boston-Edison) may require additional review
- Detroit Land Bank Authority properties sold for ADU development subject to DLBA deed restrictions
How Many ADUs Are Allowed?
Number of ADUs Allowed in Detroit: Single-family lots: not confirmed — see official source. Multifamily properties: not confirmed — see official source.
- Single-Family Lots
- 1 ADU per lot
- Multifamily Properties
- Accessory units on multifamily parcels subject to site plan review
Statewide Preemption
ADU Preemption
We could not confirm a statewide ADU preemption statute for Michigan.
View Michigan preemption detailsFrequently Asked Questions
Can I build an ADU in Detroit?
Yes. Detroit, MI allows accessory dwelling units. On a single-family lot you can build 1 ADU per lot.
How big can an ADU be in Detroit?
The maximum size for a detached ADU in Detroit is 800 square feet.
How long does it take to get an ADU permit in Detroit?
The typical ADU permit timeline in Detroit is Detroit Buildings, Safety Engineering and Environmental Department (BSEED): ADU permits typically 6-10 weeks for plan review. Construction 3-8 months depending on contractor availability. Detroit's construction labor market has grown with the city's comeback.. Total estimated permit fees are $1,000-$4,500 total permit fees.
Do I need extra parking for an ADU in Detroit?
Detroit parking rules for ADUs: One parking space required per ADU. Detroit's auto-centric legacy means most parcels have a detached garage or paved pad. New ADU construction in converted garages may require a replacement parking space be created elsewhere on the parcel.
Do I have to live on-site to have an ADU in Detroit?
Owner-occupancy requirement in Detroit: No owner-occupancy requirement under current Detroit ADU ordinance. Detroit's land vacancy context encourages flexible occupancy to maximize use of distressed properties.
Source: Detroit City Code Chapter 61 (Zoning); Detroit BSEED Permit Requirements. Last verified April 6, 2026. View source