San Mateo County, CA Fence Regulations: Permit Requirements (2026)

In unincorporated San Mateo County, the Planning and Building Department and Public Works administer fence approvals. According to the county's fence guidance, no building permit is required for a wooden or cyclone (chain-link) fence that complies with the zoning height limits in Chapter 8.332. A building permit is required where a fence is constructed above a retaining wall, where the fence is masonry, or where it exceeds the height that zoning allows by right. Working in the public right-of-way requires an encroachment permit from Public Works, and confirming a property line may require a boundary survey. Under the California Building Code (Section 105.2, adopted countywide), fences over 7 feet high and retaining walls over 4 feet (measured from the bottom of the footing) — or any retaining wall supporting a surcharge — also require a building permit. To build taller than the by-right limits, an applicant must obtain a Fence Height Exception under Section 8.332.040 (available only outside the Coastal Zone), which the county estimates costs roughly $2,600 and takes about 2 to 4 months, including notice to property owners within 300 feet. Always confirm current requirements with the Planning and Building Department before construction.