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

Section 210-12 of the Floodplain Management Regulations establishes the local design flood elevation, or LDFE, that governs new construction in flood hazard areas. The LDFE combines the flood hazard areas set under Section 210-11 with the Flood Hazard Area Control Act's minimum statewide elevation requirements for lowest floors in A, Coastal A, and V Zones, ASCE 24 requirements for critical facilities, and additional freeboard the chapter adds on top. At minimum, for a delineated watercourse the LDFE is the best-available flood hazard data elevation plus one foot, or the freeboard described by N.J.A.C.

7:13, whichever governs. For an undelineated watercourse with 50 acres or more of contributory drainage area, an applicant must supply either an unexpired NJDEP flood hazard area verification plus one foot of freeboard, or a sealed Method 5 or Method 6 determination under N.J.A.C. 7:13, again plus one foot and any ASCE 24 freeboard. In AO Zones, the LDFE is the highest adjacent grade plus the FIRM's specified depth number plus one foot of freeboard, or three feet above grade if no depth number is given.

Critical facilities carry higher freeboard: Class IV critical facilities must use the higher of the 500-year flood elevation or the flood hazard area design elevation plus two feet of freeboard, while Class III critical facilities in coastal high hazard areas add one foot of freeboard to the same comparison, both under Section 210-12B.