Santa Clara County, CA Building Setbacks & Zoning: Lot Coverage Limits (2026)

Lot coverage in the unincorporated county is defined in Zoning Ordinance Section 1.30.030 as the footprint of all buildings and structures over 30 inches in height; covered patios, carports, arbors, and similar structures count toward coverage, while eaves are excluded provided they do not project more than two and one-half feet. The applicable percentage limit depends on the zoning district. In the base district development-standards tables, many lower-density urban residential and rural districts do not list a numeric coverage cap (shown as no applicable standard), while the R3 multi-family district is capped at 50 percent lot coverage in Table 2.30-3. Where the Neighborhood Preservation combining district (Section 3.40.050) applies, single-family development may not exceed 20 percent lot coverage and two-family and multi-family development may not exceed 35 percent, with accessory dwelling units and certain state-law housing exempt from those limits. Detached accessory buildings in urban residential districts also carry a separate rule limiting cumulative rear-yard coverage by such buildings to 30 percent under Section 4.20.020. Because the controlling figure depends heavily on district, combining-district overlays, and development type, owners should confirm the exact lot-coverage limit for their parcel with the County Department of Planning and Development before designing an addition or new structure.