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

Added September 13, 2022 by Ordinance No. 2022-17, Section 21-802A.3 builds the Local Design Flood Elevation from the best available flood hazard data sources, and the Flood Hazard Area Control Act Minimum Statewide elevation requirements for lowest floors in A, Coastal A, and V zones, ASCE 24 requirements for critical facilities as specified by the building code, plus additional freeboard. For a delineated watercourse, the floor elevation is the Best Available Flood Hazard Data Area elevation plus 1 foot of freeboard, or the freeboard required by the state Flood Hazard Area Control Act rules at N.J.A.C.

7:13, whichever governs. Where a watercourse is undelineated but drains 50 acres or more, an applicant must submit either an unexpired NJDEP Flood Hazard Area Verification plus 1 foot of freeboard, or a Method 5 or Method 6 elevation determination under N.J.A.C. 7:13, again plus 1 foot of freeboard and any added freeboard ASCE 24 requires. In AO Zones without a mapped depth number, the design elevation defaults to 3 feet above the highest adjacent grade. The freeboard climbs for critical facilities: new or substantially improved Class IV critical facilities need the higher of the 500-year flood elevation or the Flood Hazard Area Design Flood Elevation plus 2 feet of freeboard, while Class III critical facilities in coastal high hazard areas need the same comparison plus 1 foot of freeboard.