San Mateo County, CA Building Setbacks & Zoning: Structure Height Limits (2026)

Maximum building height is set by the S-District (Development Standards combining district) paired with the use district. Common S-District heights: S-100 (5,000 sq ft R-1): 36 feet and 2.5 stories; S-17 (20,000 sq ft R-1): 28 feet; Residential Hillside (RH): 28 feet with additional slope-setback requirements; Agricultural: varies. Height is measured from the average elevation of natural grade beneath the structure to the highest point of the roof (not including appurtenances). Chimneys may exceed the limit by up to 3 feet, antennas/flagpoles by the height necessary for function, mechanical equipment screening by 4 feet. Design Review combining district triggers staff or Design Review Officer approval of massing, height, and architectural character regardless of numeric compliance. Scenic Road combining districts along Highway 1, Highway 35 (Skyline), and La Honda Road impose additional ridge-line and view-corridor restrictions. Coastal Zone projects are subject to view-protection policies in the Local Coastal Program. Variances require Planning Commission hearing with findings of unique hardship.