San Francisco, CA Fence Regulations: Retaining Walls (2026)

Given San Francisco's famously steep topography, retaining walls are ubiquitous. SF Building Code Section 105.2 exempts retaining walls 4 feet or less (measured from bottom of footing to top) that do not support a surcharge (a road, driveway, building, or slope above) from building permits. Any wall taller than 4 feet, or any wall of any height supporting a surcharge, requires a building permit plus a licensed engineer's structural design stamped to current SF amendments of the CBC. Permits go through the Department of Building Inspection with plan review typical 4-8 weeks. Setback requirements vary by zoning: typically walls must be set back from the property line equal to their height in the front setback area, and may sit on the property line in rear/side yards with neighbor sign-off. Over-height walls may also trigger Planning Department review for visual impact. Geotechnical reports are required for walls over 6 feet or in documented landslide zones. Unpermitted walls that fail create major liability; post-Loma Prieta seismic retrofitting of old masonry walls is common.