Alpharetta, GA Accessory Structures: ADU Owner Occupancy (2026)

The City of Alpharetta's Unified Development Code treats an accessory 'For-Sale' dwelling as a conditioned accessory use, not a general backyard ADU program. Section 2.2.12 (O-P office-professional) and the matching accessory-use provisions in the O-I, C-1 and C-2 districts allow a residential unit attached to a commercial or office building only if it sits above or to the rear of that structure and shares a common wall with it. Occupancy is restricted: the dwelling must be occupied by a single family, one member of which owns or leases the commercial or office structure it serves, tying the unit to the business rather than allowing it to be rented out separately.

The floor area of the accessory dwelling is capped at 40 percent of the combined square footage of the commercial or office building and the dwelling together, keeping the residential component clearly secondary to the business use. Both the dwelling and its host structure must comply with the City's life safety code, building code and other standard codes before the accessory unit can be occupied. Community Development reviews these accessory dwellings during site plan and building permit review for the O-P district; there is no separate stand-alone 'ADU permit' listed in this section.

Because this rule sits inside the office-professional and commercial district use standards rather than the residential district chapters (AG, RE, R, R-4A, etc.), it does not authorize a detached backyard cottage or basement apartment on an ordinary single-family lot in Alpharetta; residential districts instead handle secondary living space through the separate general accessory-use size cap in UDC Section 2.3.3.C.