North Hempstead, NY Fence Regulations: Retaining Walls (2026)

1, added in 1996, makes it unlawful to build a retaining wall anywhere in the Town without a Building Official permit, applied for on a Building Official form. The Building Official will not issue that permit unless the application includes development plans for the land the wall will support, and any other land on the same tax lot, or unless the application shows a serious erosion, flooding, or public health and safety problem that the wall would solve, and the Building Official may demand additional information to evaluate either showing.

Height is capped by location: in a residential zoning district, or within 50 feet of one, a retaining wall cannot exceed five feet, measured from the lowest point of the adjoining grade; everywhere else the cap is eight feet. A wall can never exceed the height of the grade it retains. Applicants may still build a series of walls in a parallel step design to get around the height cap, but each pair of walls in that series needs a minimum of five horizontal feet between them, and that gap must be landscaped with natural material and kept maintained.

The section also requires the applicant to accommodate stormwater on the property both during and after construction. Walls that were already built and backfilled before the section took effect are grandfathered from the height limits; the Building Official or a licensed engineer or architect can approve repairs to an unsafe grandfathered wall if the repaired structure stays the same size or smaller, but any wall that is demolished or abandoned must be rebuilt to current standards if replaced.