Durham County, NC Fence Regulations: Retaining Walls (2026)

5, Article II, Division 3) requires that any new construction or substantial improvement in a Special Flood Hazard Area be built on fill raised two feet above the base flood elevation. The default method extends flat fill 40 feet out from the building's exterior walls (or to the property line if it is closer), tapering down on a slope no steeper than 3:1: the code's own example is 31 feet of flat fill plus nine feet of sloped fill for a three-foot-deep fill pad. Sec.

5-71(10) lets a property owner substitute a retaining wall for that sloped edge instead of grading a long slope, for example holding a flat side yard behind a wall rather than sloping the fill down to grade. Nonhabitable residential accessory structures are exempt from the 40-foot apron requirement but must still sit on fill two feet above base flood elevation. Anyone who cannot meet these standards because of special stormwater considerations can seek an exception from the Development Review Board (DRB) under Sec. 5-54, but only on a recommendation from the county engineer's office; the DRB must find good cause, unusual hardship, and no increase in flood risk before granting relief.

The city-county Director of Inspections, appointed under Sec. 5-51, administers this article for both fill grading and any retaining wall built as its substitute. This flood-hazard-area standard is separate from any general engineering or height standard for retaining walls elsewhere in the county, which falls under the joint Durham City-County Unified Development Ordinance rather than this chapter.