Farmington Hills, MI Accessory Structures: ADU Rules (2026)

Farmington Hills' Chapter 34 Zoning Ordinance does not include provisions permitting accessory dwelling units (ADUs) — defined as a separate, self-contained second dwelling unit on a single-family lot. The City's residential districts (RA-1, RA-2A, RA-2B, RA-3, RA-4) are designed for one principal dwelling per lot. Anyone wishing to add a second kitchen, second living unit, or detached cottage on a single-family lot would face a Zoning Ordinance violation absent a use variance from the Zoning Board of Appeals or a planned development approval. Internal in-law arrangements (a relative living in part of the principal dwelling without a separate kitchen or second utility connection) are not regulated as ADUs but are still constrained by the single-family use definition. Michigan has no statewide ADU mandate as of 2026. The 2025-2026 'Michigan Housing Forward Act' package — HB 5529, HB 5530, HB 5531, HB 5532, HB 5581-5585 — introduced in late 2025 would, if enacted, preempt local zoning and require ADUs to be permitted by-right in residential districts (HB 5585 in particular establishes a statewide ADU definition, prohibits public hearings, removes owner-occupancy requirements, and bars additional parking). As of February 2026 these bills were still in the House Committee on Regulatory Reform with the Michigan Municipal League and Michigan Townships Association actively opposing. The earlier HB 5184 of 2023 (ADU bill) was not enacted; HB 5184 of 2025 deals with worker's compensation, unrelated to ADUs.