Brookhaven, NY Environmental Rules: Flood Elevation Requirements (2026)

Section 33-5C sets elevation standards for residential structures outside coastal high-hazard areas. In Zones A1-A30, AE and AH (and Zone A where base flood elevation data exist), the lowest floor, including any basement, must sit at or above two feet above the base flood elevation. Where Zone A has no base flood elevation data, the floor must instead be at least three feet above the highest adjacent grade. In Zone AO, the floor must be elevated above the highest adjacent grade at least as high as two feet above the depth number printed on the Flood Insurance Rate Map, or two feet if no depth number is given.

Section 33-5D covers coastal high-hazard areas (Zones V1-V30, VE, V, or an area of moderate wave action): new construction and substantial improvements must be elevated on pilings, columns, or shear walls so the bottom of the lowest horizontal structural member supporting the floor sits two feet above base flood elevation, engineered to withstand simultaneous wind and water loads. Fill and spread footings cannot be used for structural support in these coastal zones. Enclosed space below the lowest floor is limited to parking, building access, or storage, and must include flood vents meeting a minimum of one square inch of net opening per square foot of enclosed area, with openings no higher than one foot above the lowest adjacent grade.

After the lowest floor is completed, the permit holder must submit an as-built elevation certificate, prepared by a licensed land surveyor or professional engineer, to the Chief Building Inspector under § 33-4D(4).