MI HB5585

Accessory dwelling units (ADUs) up to 800 square feet or 75% of the main dwelling size (whichever is less) become permitted uses in all residential zones without public hearings or discretionary approval.

ADUs are exempt from parking requirements, owner occupancy mandates, and dwelling unit density calculations under local zoning ordinances.

Mobile homes cannot be excluded from any residential zone, including through aesthetic or construction material restrictions not necessary for public safety.

Zoning ordinances cannot impose design, aesthetic, height, or placement requirements on ADUs that are stricter than those applied to the primary dwelling.

The act takes effect 180 days after enactment and allows local governments to retroactively approve ADUs built without prior approval.