ADU Rules in Detroit, MI (2026)
ADU rules, permit requirements, size limits, and fees for Detroit, MI. Source-cited from official municipal code.
Yes, ADUs are allowed in Detroit, MI.
Detroit, MI permits accessory dwelling units (ADUs) on residential properties. ADUs — also called granny flats, in-law units, backyard cottages, or secondary suites — are secondary housing units on a single-family or multifamily lot. State and local law governs the approval process. In Detroit, the Detroit Buildings, Safety Engineering and Environmental Department (BSEED) handles ADU permit applications. Below you will find the current size limits, setbacks, fees, and timeline for building an ADU in Detroit.
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: $150-$800. Building permit fee: Based on construction value — typically $800-$3,500. 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: 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. Apply through the Detroit Buildings, Safety Engineering and Environmental Department (BSEED) online permit portal. Phone: (313) 224-3158.
Setback Requirements
ADU Setback Requirements in Detroit: Front setback: follows zone standard. Side setback: no minimum. Rear setback: no minimum.
Parking Requirements
Parking Requirements: 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.
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: 1 ADU per lot. Multifamily properties: Accessory units on multifamily parcels subject to site plan review. Detroit's shrinking city context creates unique opportunities: some homeowners purchase adjacent vacant DLBA lots to build a standalone ADU on a newly consolidated parcel. This requires lot consolidation through the City of Detroit.
- 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 detailsHistoric District Considerations
Historic District Requirements: Detroit has 12 historic districts where additional design review may be required for ADU construction. Design review approval is required before obtaining a building permit for properties in historic overlay zones. Detroit Historic District Commission (HDC) designates local historic districts. Notable districts include Boston-Edison Historic District (192 homes), Indian Village, Woodbridge Historic District, West Canfield Historic District, and the Lafayette Park Historic District. Certificate of Appropriateness required for exterior changes to structures in designated districts. Detroit also has National Register Historic Districts including Midtown and Corktown which have federal tax credit implications but less restrictive local review. Look up historic district boundaries at: https://detroitmi.gov/departments/planning-development-department
Frequently 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