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Brookhaven, GA Accessory Structures: ADU Rules (2026)

Some Restrictions

Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

ADU rules in Brookhaven, GA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.

Key Facts

Where allowed: Only on lots occupied by a detached house
Number per lot: One DADU and one AADU
Maximum size: 50 percent of principal floor area or 1,000 square feet, whichever is less
Parking: No additional parking required
DADU height: 24 feet or two stories (Table 2-9)
Separation from house: 10 feet for a detached ADU
Adopted: Ord. No. RZ2023-12-10, December 19, 2023

ADU Eligibility Quick-Check

An Accessory Dwelling Unit (ADU) is a smaller, independent living unit on the same lot as a single-family home: converted garages, detached cottages, basement or attic conversions, and attached additions all qualify. Most states have streamlined ADU permitting since 2020, but local rules still control size, height, and setback.

Is your lot zoned single-family or multi-family residential?
Does your lot have at least 1,200 sq ft of buildable space?
Is your existing home owner-occupied (in most states this is not required, but some require it for ADU permits)?
Will the ADU stay under your state's size cap (commonly 850-1,200 sq ft for detached)?
Can you provide one off-street parking space (waived in many states within 0.5 mi of transit)?

If you answered 'yes' to most of these, you likely qualify in Georgia under recent ADU streamlining laws. The Brookhaven, GA rules below cover local size, height, and setback requirements.

Summary

In the City of Brookhaven, Georgia, section 27-133 allows accessory dwelling units only on lots occupied by a detached house. One detached ADU and one attached ADU are allowed per lot, together capped at 50 percent of the principal dwelling's gross floor area or 1,000 square feet, whichever is less. No additional parking is required. Table 2-2 permits ADUs in RS, R3, RSA and RM districts.

(a)Where allowed. ADUs are allowed only on lots occupied by a detached house. ADUs must be secondary and subordinate to the principal dwelling unit of the subject property.(b)Zoning district regulations. ADUs are subject to all applicable regulations of the zoning district in which they are located, unless otherwise expressly stated in this chapter.(c)Number. No more than one DADU and one AADU is permitted on a single lot.(d)Size. The total square footage of all ADUs on a single lot cannot exceed 50 percent of the gross floor area of the principal dwelling unit, or 1,000 square feet, whichever is less.(e)Number of residents. The total number of residents that reside on the subject property may not exceed the number permitted for a single household.(f)Parking. No additional parking is required for an ADU. Any provided parking is subject to the same regulations that apply to the principal dwelling unit.

View official code

Full Breakdown

Division 7 of article II of chapter 27 was rewritten by Ord. No. RZ2023-12-10, adopted December 19, 2023, replacing the earlier backyard cottage rules. Table 2-2 in section 27-55 marks Accessory Dwelling Unit as permitted in all four residential building-type columns: RS, R3, RSA and RM.

Section 27-133 sets the ground rules. ADUs must be secondary and subordinate to the principal dwelling unit and are subject to all applicable regulations of the zoning district unless the chapter expressly says otherwise. No more than one DADU and one AADU is permitted on a single lot. The total number of residents on the property cannot exceed the number permitted for a single household. No business activity is permitted in an ADU unless it meets the requirements of a home occupation. Parking is not added: any parking provided follows the rules for the principal dwelling unit.

An attached ADU (AADU) is contained wholly within the detached house, created by converting interior floor area such as an attic or basement, by adding floor area to an existing house, or by building a new house that includes the unit (27-134). Only one entrance to a detached house containing an AADU can face a street, unless the house already had an additional street-facing entrance before the AADU was created.

A detached ADU (DADU) is a free-standing structure and must meet Table 2-9 in section 27-135. Front street: permitted behind the front wall plane of the principal dwelling. Side street: 20 feet in RS and 15 feet in R3, RSA and RM. Interior side: 10 feet. Rear: 10 feet, with a footnote requiring a minimum 20-foot rear setback for accessory buildings when the rear yard adjoins the side yard of an abutting lot. Separation from principal buildings: 10 feet. Height: 24 feet or two stories. Floor area: 50 percent of the principal residential structure.

Section 27-133(j) lets ADUs go on a nonconforming lot with a detached house if all setback and building regulations are met, and lets existing non-conforming enclosed accessory structures as of December 19, 2023 convert to an ADU without exceeding their existing noncompliance. Owner occupancy and rental limits are covered on a separate page.

Violations & Fines

An ADU built outside these limits violates section 27-1221 as a use or structure inconsistent with the zoning ordinance. The community development director can withhold or revoke building permits and order work stopped (27-1223). For a non-emergency violation the property owner has ten days from written notice to correct it (27-1228(a)). Each day after notice is a separate violation with a separate citation (27-1222), and the city can also cite the violator into municipal court (27-1224).

Frequently Asked Questions

Can I build a backyard unit on any lot in Brookhaven?

Only on a lot occupied by a detached house. Section 27-133(a) allows ADUs only there and requires them to be secondary and subordinate to the principal dwelling unit. Table 2-2 permits the ADU building type in RS, R3, RSA and RM districts. The lot must also meet the DADU setbacks in Table 2-9 or the nonconforming-lot rule in 27-133(j)(1).

How big can an ADU be?

Section 27-133(d) says the total square footage of all ADUs on a single lot cannot exceed 50 percent of the gross floor area of the principal dwelling unit, or 1,000 square feet, whichever is less. Table 2-9 also caps a detached ADU at 50 percent of the floor area of the principal residential structure.

Do I need extra parking for an ADU?

No. Section 27-133(f) states that no additional parking is required for an ADU. Any parking that is provided is subject to the same regulations that apply to the principal dwelling unit. The section does not add a parking count for either the attached or the detached unit.

Can I convert an existing garage or shed into an ADU?

Section 27-133(j)(2) allows non-conforming and enclosed accessory structures that existed on December 19, 2023 to be converted to an ADU as long as the change does not push the structure past its existing extent of noncompliance with article 2 of chapter 27. A conversion still counts toward the one DADU per lot limit.

Sources & Official References

[1]Code of the City of Brookhaven, Georgia, Chapter 27 Zoning (Municode)

Other rules in Brookhaven

Shed & Carport RulesSome Restrictions Parking Rules: RV & Boat ParkingSignificant Restrictions ADU Owner OccupancySignificant Restrictions Parking Rules: EV ChargingSome Restrictions Parking Rules: Commercial & Oversized VehiclesSignificant Restrictions Parking Rules: Driveway RulesSome Restrictions Fence Regulations: Retaining WallsSignificant Restrictions Fence Regulations: Material RestrictionsSome Restrictions

All Brookhaven rules

How Brookhaven compares: Easiest Cities to Build an ADU·Compare Brookhaven to another location·View the Georgia accessory structures overview

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