Fulton County, GA Accessory Structures: ADU Rules (2026)
ADU rules in Fulton County, GA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Units per lot
- 1 guest house per lot
- Size range
- 650 to 1,500 sq ft heated
- Placement
- Rear yard only
- Kitchen
- Separate kitchen facility allowed
- Setbacks
- Same as principal building
- Scope
- Unincorporated Fulton County only
Summary
Unincorporated Fulton County allows one detached accessory dwelling, called a guest house, per single-family lot in Suburban, R-1 through R-6, TR, AG-1 and related districts. Zoning Resolution §§ 3.3.7 and 19.3.5 cap heated floor area between 650 and 1,500 square feet, require the structure to sit in the rear yard, allow a separate kitchen, and hold it to the same setbacks as the main house.
Guest House. A detached accessory dwelling unit located on the same lot with a single-family dwelling unit. ... 19.3.5 Guest house. A.Required districts: Suburban A, Suburban B, Suburban C, R-1, R-2, R-2A, R-3, R-3A, R-4, R-4A, R-5, R-5A, R-6, NUP, CUP, TR, A, A-L, AG-1, O-1 and MIX when accessory to a single-family dwelling.B.Standards:...2.A separate kitchen facility shall be allowed.3.Heated floor area shall be a minimum of 650 square feet and a maximum of 1500 square feet.4.Principal building setbacks shall apply.5.The location shall be limited to the rear yard.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 57).
Full Breakdown
5 sets the standards that govern it in unincorporated Fulton County only; Atlanta, Sandy Springs, Johns Creek, Milton, Chattahoochee Hills and South Fulton residents follow their own city zoning instead. The use is allowed, without a separate use permit, in Suburban A, B and C, R-1, R-2, R-2A, R-3, R-3A, R-4, R-4A, R-5, R-5A, R-6, NUP, CUP, TR, A, A-L, AG-1 and O-1 districts, and in MIX districts when accessory to a single-family dwelling. Only one guest house structure is allowed per lot. Heated floor area must fall between 650 and 1,500 square feet, and the structure must observe the same principal building setbacks that apply to the main house on the lot.
Placement is restricted to the rear yard only, so a guest house or garage apartment cannot go in a front or side yard regardless of lot size. 3. Because the guest house is capped at 1,500 square feet, it cannot be built to a size that would functionally duplicate the principal dwelling, and it still needs its own building permit review by the Department of Environment and Community Development under the county's building code. 5(B)(1)'s occupancy standard, not by this dimensional rule.
Violations & Fines
Building a guest house larger than 1,500 square feet, adding a second detached accessory dwelling on the same lot, or placing it outside the rear yard is a zoning violation the Department of Environment and Community Development can flag through a notice to comply or stop-work order, appealable to the Board of Zoning Appeals. Fulton County's general Code § 1-8 penalty, up to $1,000.00 and 60 days in jail, applies where the Zoning Resolution sets no specific fine.
Frequently Asked Questions
Can I build a garage apartment or in-law suite in Fulton County?
How big can a Fulton County guest house be?
Does this zoning rule apply inside Atlanta or Sandy Springs?
Sources & Official References
Other rules in Fulton County
How Fulton County compares: Easiest Cities to Build an ADU·Compare Fulton County to another location·View the Georgia accessory structures overview
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