Huntsville, AL Accessory Structures: ADU Permits (2026)

Alabama has not enacted statewide ADU-by-right legislation comparable to California Government Code §65852.2. As a Dillon Rule state, Huntsville exercises only those zoning powers delegated by the Alabama Legislature under Title 11 Chapter 52 of the Alabama Code (Municipal Planning and Zoning). The Huntsville Zoning Ordinance — adopted under Code of Ordinances Chapter 17 and maintained separately — defines a dwelling and accessory structures, with detached accessory living quarters allowed in certain Residence Districts subject to lot-area, setback, and height limits in Article 72 (Supplementary District Regulations). Most single-family Residence 1 (R-1A, R-1B, R-1C, R-2) districts allow an accessory structure containing living quarters for domestic employees or family members; rental of the unit to non-family tenants generally requires a Residence 3 (R-3) zoning or a use variance from the Huntsville Board of Zoning Adjustment. Building permits are issued by the Huntsville Inspection Department (320 Fountain Circle SW), which enforces the 2021 International Residential Code, 2020 National Electrical Code, and 2021 International Plumbing/Mechanical Codes adopted by reference in Code of Ordinances Chapter 6. Properties within the Twickenham, Old Town, or Five Points historic preservation districts also require Certificate of Appropriateness from the Huntsville Historic Preservation Commission under Zoning Ordinance Article 64.