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

Section 220-5C of Chapter 220, Flood Damage Prevention, sets tiered elevation standards by zone. Where base flood elevation data exists for Zones A1-A30, AE and AH, and for Zone A when data is available, new construction and substantial improvements must have the lowest floor, including any basement, elevated to or above two feet above the base flood level. Where Zone A has no base flood elevation data, the lowest floor must instead sit at least three feet above the highest adjacent grade. In Zone AO, the lowest floor must be elevated above the highest adjacent grade at least as high as two feet above the depth number shown on the Town's Flood Insurance Rate Map, or two feet if no depth number is listed, and Zones AH and AO both require drainage paths that route floodwater around and away from structures on slopes.

Nonresidential structures get an alternative: floodproofing the building watertight to two feet above the base flood level, with a licensed engineer or architect certifying the design can resist hydrostatic and hydrodynamic loads. Applicants must submit the proposed elevation in relation to mean sea level with their floodplain development permit application, and once the lowest floor is built, a licensed engineer or surveyor must certify the as-built elevation to the Town Engineer before a certificate of compliance issues. L. No. 2-2013) that also refined the basement definition.