San Mateo County, CA Fence Regulations: Material Restrictions (2026)

The general fence rules for unincorporated San Mateo County in Zoning Regulations Chapter 8.332 are height- and placement-based and do not broadly prohibit fence materials; the county's fence guidance specifically references wood and cyclone (chain-link) fences as standard, permit-exempt options when within height limits. Material restrictions appear in certain district-specific and design-review standards rather than the countywide rule. For example, several district standards in the Zoning Regulations provide that where fences are visible and within 15 feet of street-facing property lines, fences may not exceed 4 feet, masonry walls are not permitted, and chain-link and corrugated-metal fences are prohibited. These context-specific rules are tied to particular zoning districts (such as North Fair Oaks and similar planned/design-reviewed areas) and to street-facing visibility, not to the entire unincorporated county. Masonry fences and walls also trigger a building permit even when wood or cyclone fences of the same height would not. When a Fence Height Exception is requested, the Director of Planning and Building may condition approval on specific design, materials, colors, and landscaping to ensure neighborhood compatibility under General Plan Policy 4.14. Because material rules vary by district and overlay, confirm your parcel's zoning and any Design Review or Coastal requirements with the Planning and Building Department.