HB 5585
Legalizing Accessory Dwelling Units (ADUs) by Right
House Bill 5585 updates Michigan’s Zoning Enabling Act to require that accessory dwelling units (ADUs) be permitted in residential zones under clear statewide standards.
Today, many local zoning ordinances either prohibit ADUs outright or subject them to discretionary review, owner-occupancy mandates, parking requirements, or restrictive design standards. HB 5585 establishes uniform protections to ensure ADUs are allowed as a permitted use.
What the bill does
Defines “accessory dwelling unit” (ADU) as a secondary dwelling unit incidental to a primary dwelling on the same parcel.
Requires ADUs to be a permitted use in any residential district if the following conditions are met:
The ADU is no larger than:
800 square feet, or
75% of the gross floor area of the primary dwelling (whichever is less).
The ADU and primary dwelling are set back at least:
5 feet from rear property lines
5 feet from side property lines
The ADU is located in a residential district.
The ADU is constructed:
Within an existing or new single-family home,
Attached to a single-family home, or
As a detached structure on a lot with a single-family home.
Protects ADUs by-right:
ADUs may only be subject to nondiscretionary administrative review (no public hearing required).
ADUs must be excluded from dwelling unit density calculations.
ADUs cannot be subject to parking requirements.
ADUs cannot be subject to owner-occupancy requirements.
Local governments cannot impose design, aesthetic, height, or placement standards more restrictive than those applied to the primary dwelling.
Local governments cannot prohibit or require basements for ADUs.
Allows retroactive approval of previously built ADUs.
Separately, the bill also prohibits local governments from excluding mobile homes from residential zones through direct or indirect zoning restrictions.
Why this matters
ADUs are one of the most cost-effective and neighborhood-compatible ways to expand housing supply. They allow:
Homeowners to add rental income
Housing options for seniors or adult children
Small-scale infill without major neighborhood changes
More efficient use of existing infrastructure
However, local zoning rules often block ADUs through discretionary review, parking mandates, or owner-occupancy restrictions.
HB 5585 ensures that modestly sized ADUs are allowed by right under clear standards, reducing barriers while preserving setback, size, and safety requirements.
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2/24/2026: Introduced by Representative Luke Meerman
Referred to Committee on Government Operations
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Luke Meerman (District 89)
Stephen Wooden (District 81)
Carrie Rheingans (District 47)
Kristian Grant (District 82)
Brenda Carter (District 53)
Sharon MacDonell (District 56)
Jasper Martus (District 69)
Jason Hoskins (District 18)
Tom Kunse (District 100)
Carol Glanville (District 84)
Jason Morgan (District 23)
Noah Arbit (District 20)
Jimmie Wilson (District 32)
Cynthia Neeley (District 70)
Kimberly Edwards (District 12)
Amos O'Neal (District 94)
Matt Longjohn (District 40)
Joey Andrews (District 38)
Mai Xiong (District 13)
Tyrone Carter (District 1)
Penelope Tsernoglou (District 75)
Joseph Tate (District 9)
Kathy Schmaltz (District 46)
Joseph Aragona (District 60)
Donavan McKinney (District 11)
Helena Scott (District 8)
Jennifer Wortz (District 35)
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