Clayton County, GA Accessory Structures: ADU Rules (2026)

Clayton County regulates accessory dwellings in its zoning ordinance, Appendix A of the county Code of Ordinances, under Sec. 6.9, standard AS-05. Subsection A defines the category broadly: basement quarters, garage quarters, caretaker or other employee quarters, guest houses, mother-in-law suites, and any other accessory dwelling as determined by the Zoning Administrator. The label on the building plans does not control; the Zoning Administrator decides whether a space counts.

Permission comes only as a conditional use, which means a discretionary approval rather than a by-right building permit, and only in three districts: AG (Agriculture), ER (Estate Residential) and RS-180. The standard lists no other district. The dwelling can sit inside the principal house or stand alone on the lot, and each form carries its own conditions.

An accessory dwelling contained within a principal dwelling is limited to one per principal dwelling unit. Its only single access point cannot be a separate exterior entrance, so the unit cannot be reachable solely from its own outside door. It needs one additional parking space and must meet all building and health code standards.

A freestanding accessory dwelling is limited to one per residential lot. It can occupy the second floor over a detached garage or be a separate structure, but it belongs only in the rear yard. It must meet the minimum setbacks for accessory structures in Article 3 of the ordinance and the minimum lot area for its district, with a hard floor: no accessory dwelling can go on a lot under 12,000 square feet. One additional parking space serves the unit.

Two general rules in the same section apply alongside AS-05. In the agricultural district (AS-01) and in the single family and two family districts (AS-02), accessory uses and structures are allowed only with, and on the same lot as, the primary use or structure, and cannot be placed on a lot before the primary use or structure is established unless the ordinance says otherwise. Conditional uses for each district are specified in Article 3.