Macon-Bibb County, GA Accessory Structures: ADU Rules (2026)

01 of the Comprehensive Land Development Resolution treats an accessory dwelling unit, described in the chapter heading as an 'Accessory Dwelling Unit/Garage Apartment,' as a conditional use that must sit on the same lot or tract as the principal residence; only one ADU of any type is allowed per lot, and no lot may carry more than two single-family dwellings total. ADUs do not count toward the lot's density calculation. The living area must measure at least 350 square feet and no more than 1,250 square feet, and in no case may it exceed 50 percent of the principal residence's size.

An ADU may be built as an addition attached to the existing structure, as a freestanding detached structure, or created inside the existing house by converting a basement, wing or attic into a separate unit; it may include its own kitchen. A detached ADU cannot exceed the height of the principal structure, must match its architectural style, roofline, materials and finish, must be sited in the rear yard, and its windows, doors, porches and decks must be placed to protect neighbors' privacy. Every ADU must still meet the zoning district's ordinary setback and height limits, needs one additional on-site parking space (tandem or grass surfacing allowed), and needs at least 20 feet of unobstructed street access.

Before a building permit issues, the applicant must show the executive director that septic capacity, where applicable, serves both units. An ADU cannot be sold separately or condominiumized unless the property is properly subdivided, and a mobile or manufactured home cannot serve as an ADU outside a district that allows manufactured homes as primary residences. The section was amended in its entirety by a resolution adopted December 9, 2024.