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Permit guides

ADU Permits in Santa Clara: a Homeowner's Guide

What you can build, which permits you need, and how the review actually works — in plain language.

Last updated October 2026. Rules change; always confirm current requirements with the city before you build.

Who handles your permit

The City of Santa Clara's Permit Center (Community Development) sits at City Hall, 1500 Warburton Ave. — (408) 615-2420, Building Division (408) 615-2440, Monday–Friday 8 a.m. to 5 p.m. Submittals go through the Permitting Online Portal (POP), available 24/7, with a guided Permit Assistant for picking the right application. Don't confuse the city with Santa Clara County — the county runs a separate pre-approved ADU program and its own Public Permit Portal for unincorporated areas.

What you can build

Santa Clara follows state ADU law but adds its own standards — a generous height allowance and a size step based on lot area:

There is no minimum lot size under state law, and converted structures keep their existing footprint and setbacks.

Pre-approved plans — with real standards behind them

The city's Pre-Approved ADU Plans Program: builders, designers, and licensed architects/engineers submit plan sets, and the Building Division pre-approves those meeting the Building, Residential, Green, Energy, and Reach codes. You buy the plan set from the designer, then submit a site-specific plan set — ADU location, utilities, zoning compliance — for your building permit.

The RB08 checklist gives the standards teeth: miss them and you can't use the pre-approved path — you face full Architectural Review under Chapter 18.76 instead. Above 18 feet with multi-story elements, those elements need 15-foot rear setbacks, dormers are capped at 40% of the elevation width, and egress windows must face the primary residence.

What goes into the submittal

1. Register in the Permitting Online Portal and use the Permit Assistant to select the right application.
2. Site-specific plan set: site plan, floor plans, elevations, structural details and calculations, Title 24 energy compliance, and CalGreen items.
3. Coordinate electrical early with Silicon Valley Power — the city's own electric utility handles service upgrades, shutoffs, and reconnections on its own schedule.
4. Corrections, fees, permit. Respond to comments through the portal. The city must act within 60 days of a complete application.

Where applications usually get stuck

• Open code enforcement cases — a violation on file must be resolved with the Permit Center before you create ADU plans.
• Designs missing the ministerial standards — outside the checklist, you're in Architectural Review (Chapter 18.76), a much longer road.
• Multi-story height rules — the 15-foot rear setback and egress-window orientation catch designers who only read the 25-foot headline.