Santa Clara County, CA Fence Regulations: Retaining Walls (2026)

In unincorporated Santa Clara County, the Zoning Ordinance treats retaining walls differently from buildings and fences. Section 4.20.020(B)(2) expressly exempts retaining walls from the accessory-building and accessory-structure regulations of that chapter, and the design review exemption list includes retaining walls that are not subject to a grading permit. That means a retaining wall is not capped at the zoning building heights, but it remains subject to building and grading permit rules and to slope and grading standards in hillside areas. The building-permit threshold comes from the California Building Code, which the County administers: a retaining wall that is not over 4 feet in height, measured from the bottom of the footing to the top of the wall, generally does not require a building permit, but any wall supporting a surcharge (such as a slope, structure, or driveway load) requires a permit regardless of height. Grading work associated with a wall can independently trigger a grading permit. In design review and viewshed overlay areas, taller or stepped retaining walls visible from sensitive areas can face additional standards and may require a public hearing. Because thresholds depend on wall height, surcharge, and site conditions, owners should confirm requirements with County Planning and Development before construction. These rules apply only to unincorporated land; cities administer their own wall and grading permits.