Southampton Village, NY Environmental Rules: Flood Elevation Requirements (2026)

Section 62-17 sets the elevation rule for new and substantially improved residential structures in the Village's areas of special flood hazard, outside the coastal high hazard areas and Coastal A Zones that § 62-18 covers separately. Three situations are spelled out.

In Zones A1-A30, AE and AH, where base flood elevation data are available, the top of the lowest floor, including a basement, must be elevated to or above two feet above the base flood elevation. In Zone AH, adequate drainage paths are required to guide floodwaters around and away from structures on slopes.

In Zone A, where no base flood elevation data are available, the elevation is set one of two ways: obtain and reasonably use data from a federal, state or other source plus two feet of freeboard, or determine it by accepted hydrologic and hydraulic engineering practice plus two feet of freeboard. A registered design professional must document that the methods reflect currently accepted engineering practice, and the studies and computations must be detailed enough for thorough review and approval. For subdivisions and other developments greater than either 50 lots or five acres, § 62-13(H) puts the job of providing the data on the permit applicant.

In Zone AO, the lowest floor, basement included, must be elevated above the highest adjacent grade at least as high as the depth number printed on the Flood Insurance Rate Map, plus one foot of freeboard. Where an AO zone shows no depth number, the depth is taken as two feet.

The elevation is verified, not assumed. The permit application states the proposed elevation of the top of the lowest floor in relation to mean sea level, and after the floor is built the permittee submits an as-built elevation certified by a licensed professional engineer or surveyor (§ 62-13(A)). Equipment gets a matching margin: new and replacement electrical, heating, ventilating, air conditioning and plumbing service equipment must sit at least two feet above base flood elevation or be designed to keep water out (§ 62-16(C)). Fully enclosed areas below the lowest floor are limited to parking, building access or storage, need openings no higher than one foot above grade, and enclosed areas sub-grade on all sides are considered basements and are not permitted (§ 62-16(B)(3)).