Do I need a permit for addition or structural alteration in Brookhaven?

Yes. In Georgia, addition or structural alteration generally requires a permit, and Brookhaven is no exception.

Additions and any change to load-bearing walls require a permit and reviewed plans in Georgia; removing or altering a bearing wall usually needs engineered details. Additions may trigger energy-code, zoning, and setback review, so confirm the full scope before starting. DeKalb County's own permitting office is the DeKalb County Planning and Sustainability, reachable on 404-371-2155 at https://dekalbcountyga.gov/departments/planning-and-sustainability/permits-plan-review-and-inspections. Its online permit portal is https://epermits.dekalbcountyga.gov/. It issues permits for the unincorporated county. If your city does not run its own building department, and many smaller Georgia municipalities do not, this is the office that will handle the job. DeKalb County sits inside the Metropolitan North Georgia Water Planning District, created by the Georgia General Assembly in 2001. Every local government in the District, cities included, has to adopt the District's model post-construction stormwater ordinance or an equivalent one at least as effective, so these rules follow you into any city in the county rather than stopping at the unincorporated line. An addition adds roof area, which counts as impervious surface, and a large one combined with new driveway or patio work can reach the local threshold. In practice the thresholds are aimed at larger development rather than ordinary homeowner work, so most single-family projects sit below them. Cobb County, for example, publishes its trigger as adding more than 5,000 square feet of impervious surface or disturbing more than an acre. Each local government sets its own figures, so check yours before assuming. Where it does apply, the current standard is to retain the first 1.0 inch of rainfall on the site to the maximum extent practicable, which usually means a detention or infiltration feature rather than just grading water to the street. Brookhaven routes every addition to DeKalb County for a preliminary easement review; if a sewer or water line easement is found, a full DeKalb Watershed Management review is required. Rough, framing, and final building inspections in Brookhaven are combination inspections, so every trade must be ready at the same time as the building work. The site plan must show all state waters within 75 feet of the property, including the 25-foot state buffer and the city's 50-foot and 75-foot stream buffers, plus impervious coverage tables. Inspection requests go through the Project Portal; requests received before 4 p.m. can be performed the next business day, and the city does not accept third-party inspections.