Southampton Village, NY Accessory Structures: ADU Rules (2026)

Article IX of Chapter 116 governs every accessory apartment in the Village of Southampton, New York. It was added on June 15, 2021 by Local Law No. 2-2021, the same local law that repealed the former Accessory Apartment Overlay District. Section 116-51 bars anyone from creating, constructing, altering, occupying, allowing or maintaining an accessory apartment without two approvals: an accessory apartment special permit from the Board of Zoning Appeals and a certificate of occupancy from the Department of Building. Any floor area located more than 50% below grade must satisfy the New York State Uniform Fire Prevention and Building Code before an accessory apartment is occupied there.

Lot size is the first screen. Section 116-55 sets the minimum lot area for an accessory apartment within a single-family dwelling at 7,500 square feet. Section 116-56 sets the minimum lot width at 75 feet, measured at the front building line of the principal dwelling when the lot sits on a curvilinear road or a cul-de-sac. A variance needed in connection with an accessory apartment permit is heard by the Village Board of Appeals under § 116-68.

The rest of the article fills in the unit itself. Section 116-57 allows a maximum of two bedrooms and sets a gross floor area of at least 400 square feet and no more than 50% or 800 square feet, whichever is less, of the principal dwelling. Section 116-58 allows one accessory apartment per lot. Section 116-60 requires one off-street parking space per 400 square feet, or part thereof, of livable floor area, placed at the direction of the Building Inspector. Section 116-61 requires a public hearing before the Zoning Board of Appeals and voids the permit unless the applicant obtains a building and change of use permit within 90 days after approval. Section 116-62 requires renewal every three years or upon transfer of title.