Trenton, NJ Environmental Rules: Flood Elevation Requirements (2026)

City Code § 109-17, Specific standards, applies in all areas of special flood hazard where base flood elevation data has been provided under § 109-7 or § 109-14B. For residential construction in an A or AE Zone, § 109-17A(2) requires the lowest floor, including any basement, along with attendant utilities and sanitary facilities, elevated at or above the base flood elevation plus three feet of freeboard, or as required by ASCE/SEI 24-14, Table 2-1, whichever is more restrictive. In AO or AH Zones, the lowest floor must sit above the mapped shallow-flooding depth number plus three feet above the highest adjacent grade, with drainage paths required around structures on slopes.

Nonresidential buildings in A or AE Zones face the same three-foot freeboard elevation standard under § 109-17B, or as an alternative may be floodproofed watertight up to that same height with walls substantially impermeable to water, structural components able to resist hydrostatic and hydrodynamic loads, and certification by a registered professional engineer or architect that the design meets accepted practice. Manufactured homes placed or substantially improved in a special flood hazard area must likewise be anchored per § 109-16A(2) and elevated on a permanent foundation so the top of the lowest floor sits at or above base flood elevation plus three feet. 2 foot where no floodway is designated.