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

Section 136-17 of the Town of Irondequoit Code sets the freeboard rules for residential structures outside the coastal high hazard areas. They apply to new and substantially improved residential structures in areas of special flood hazard, on top of the subdivision, encroachment and all-structure standards in § 136-15B, § 136-15C and § 136-16.

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 AH, adequate drainage paths must guide floodwaters around and away from structures on slopes. In Zone A with no elevation data, the base flood elevation is determined by using data from a federal, state or other source, or by accepted hydrologic and hydraulic engineering practice, and either way two feet of freeboard is added. A registered design professional must document the engineering method and submit studies, analyses and computations detailed enough for thorough review. In Zone AO, the lowest floor must stand above the highest adjacent grade by at least the depth number printed on the Flood Insurance Rate Map plus one foot of freeboard, and the depth number is taken as two feet where the map gives none.

Related elevation rules reach beyond floors. New and replacement electrical, heating, ventilating, air conditioning and plumbing equipment goes at or above base flood elevation unless designed to keep water out, and aboveground tanks that are not anchored must be installed at the base flood elevation plus two feet. Fully enclosed areas below the lowest floor can serve only for parking, building access or storage, and subgrade enclosures count as basements and are not permitted. Applicants submit the proposed lowest-floor elevation and an as-built elevation certified by a licensed professional engineer or surveyor.