Milpitas, CA Fence Regulations: Retaining Walls (2026)

Milpitas handles retaining walls through both its building-permit rules and its zoning fence-height standards. Under the city's Building and Safety FAQ, applying the California Building and Residential Codes, a retaining wall 'not over 4 feet in height measured from the bottom of the footing to the top of the wall' does not require a building permit, unless the wall is supporting a surcharge (an additional load such as a slope or structure above) or is impounding liquids. Any retaining wall taller than four feet, or one carrying a surcharge, requires a building permit from Building and Safety, which reviews it for structural adequacy under the engineering provisions of the building code. From a zoning standpoint, walls are treated like fences: Section C.2.040 governs the height of 'fences, walls, dense and continuous hedges, and similar structures,' and Subsection A.6.090 measures fence and wall height from finished grade to the top of the wall. Concrete block walls must be finished with stucco or decorative split-faced block and capped with a decorative cap; plain concrete block is not allowed. Where a retaining wall sits in a required setback, the zoning height limit for that setback (42 inches in a front setback, six feet in a side or rear setback on the valley floor) still applies to the visible wall portion. Owners with sloped or hillside lots should confirm requirements, since the 'H' Hillside Combining District has additional review.