Parsippany-Troy Hills, NJ Environmental Rules: Flood Elevation Requirements (2026)

Section 175-2.3 of Chapter 175 (Ord. No. 2025:15, adopted 8-5-2025) establishes the local design flood elevation, or LDFE, in the flood hazard areas defined in § 175-2.2. The LDFE is built from the best available flood hazard data, the state Flood Hazard Area Control Act minimum elevations for lowest floors in A, Coastal A and V Zones, ASCE 24 requirements for critical facilities, plus additional freeboard specified by the article.

At a minimum, § 175-2.3(B) sets the LDFE by situation. For a delineated watercourse, it is the elevation from the best available flood hazard data plus one foot, or as described by N.J.A.C. 7:13, of freeboard. For an undelineated watercourse with a contributory drainage area of 50 acres or more, the applicant must provide either an unexpired NJDEP flood hazard area verification plus one foot of freeboard and any additional ASCE 24 freeboard, or a determination using Method 5 or Method 6 under N.J.A.C. 7:13 plus one foot of freeboard and any additional ASCE 24 freeboard, sealed and submitted under §§ 175-5.2 and 175-5.3. For Zone AO, the LDFE is the highest adjacent grade plus the depth number on the FIRM panel plus one foot of freeboard, and three feet above the highest adjacent grade when no depth number is specified.

Critical facilities are treated separately. New and substantially improved Class IV critical facilities must use the higher of the 0.2% annual chance (500-year) flood elevation or the flood hazard area design flood elevation with an additional two feet of freeboard. New and substantially improved Class III critical facilities in coastal high hazard areas use the same comparison with one additional foot of freeboard. Under § 175-1.9, where these regulations conflict with another ordinance, the more restrictive governs. The Municipal Engineer serves as Floodplain Administrator and reviews applications.