Cupertino, CA Fence Regulations: Retaining Walls (2026)

200 sets the design standards for retaining walls built anywhere in Cupertino, folded into the same chapter that governs grading and excavation permits. Every wall must be designed to the latest adopted Uniform Building Code and recognized soils engineering principles and approved by the Director before construction. A wall sited at or within twice its retained height from any property line must be built from materials other than wood, a restriction the code says supersedes every other provision in the section. Once retained height passes three feet, any vertical structural member resisting the fill's overturning forces must likewise be non-wood, and the Director can force an all-non-wood design at any height if wood poses a hazard.

Past eight feet of retained height, wood is barred entirely unless the City Council itself approves it. Walls next to travelled ways must handle H10-44 truck wheel loadings under the AASHO Standard Specifications for Highway Bridges, and the Director can call in a soils engineer to set special backfill surcharge values. 200C without extra structural calculations if the Director finds no special site or soils conditions, but a civil engineer remains responsible for confirming a standard design fits the actual site. Every retaining wall needs Director approval before any building permit on the property is issued, and a plan-checking fee applies at the rate set in the City's current fee resolution. Walls over five feet must be screened with landscape material or faced with decorative material, subject to Community Development Director approval.