Edison, NJ Fence Regulations: Retaining Walls (2026)

Retaining walls used to stabilize existing or proposed steep slopes in Edison Township must be designed and certified by a New Jersey-licensed professional engineer once they reach four feet or more in height, under Township Code Section 31-2.7(b)(3). The rule sits inside Chapter 31's Steep Slope Conservation standards, which apply to any new development or land disturbance on a steep slope within the Township.

Section 31-2.4 defines a "steep slope" as any grade equal to or greater than 20% measured over a minimum ten-foot run, or a slope of 12% or more with a vertical rise of five feet or greater, calculated from two-foot contour intervals. Section 31-2.6 prohibits disturbance of steep slopes outright except for redevelopment confined to an existing impervious footprint, or new disturbance necessary to protect public health, safety or welfare, provide an environmental benefit, or avoid extraordinary hardship not created by the owner. Where a subdivision or site plan application involves steep slopes, Section 31-2.7 requires existing wooded, well-established slopes to stay undisturbed inside conservation easements, and lets the approving board require fill, restabilization and a reforestation plan for previously disturbed slopes. Retaining walls built to stabilize those slopes cannot be used to make the underlying grade look less steep: Section 31-2.7(b)(3) requires that "all slope area measurements will be calculated as if retaining walls were not used," and any wall of four feet or taller must carry a design certified by a New Jersey-licensed professional engineer before it counts toward compliance. Steep slope areas themselves must stay in an open-space condition, barred to structures except public facilities like bridges, headwalls and culverts.