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Permit guides

ADU Permits in Redwood City: 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 or county before you build.

Who handles your permit

ADU permitting in Redwood City runs through the Community Development & Transportation Department — the Planning Division is at City Hall, 1017 Middlefield Road, Redwood City, CA 94063, (650) 780-7234, planning@redwoodcity.org. Planning applications for single-family, duplex, and triplex projects are emailed as PDFs to the planning desk; the building permit then follows the building division's own submittal list. One Redwood City signature: neighbor notification happens before you submit, not after — for architectural permits, neighbors are notified and acknowledged first, then the application goes in.

What you can build

California state law sets the baseline, and Redwood City follows it:

"Pre-reviewed" ADU designs — not "pre-approved"

Through a long-running partnership with the Housing Endowment and Regional Trust (HEART) of San Mateo County, Redwood City offers pre-reviewed ADU designs — and a city planner puts it plainly: "preapproved" can be misleading, because staff still review every application. On the expedited track, the city reviews within 30 days for compliance with local standards and building codes. Redwood City also participates in San Mateo County's ADU Resource Center collaboration linking homeowners and designers.

Ask the planning division for the current design list — studio, one-bedroom, and two-bedroom options have been added over time. Site-specific work (plot plan, siting, setbacks, utilities) is always on you.

What goes into the submittal

• Completed planning application, signed by the property owner, with the application fee
• Neighbor notification forms with signed acknowledgments — or certified-mail receipts — submitted with the application
• Context plan showing adjacent homes, building footprints, and driveways
• Site plan with setbacks, drainage, and utility connections (water meter, sewer, gas, electrical panel)
• Architectural plans: floor plans, roof plan, exterior elevations, CALGreen checklist, Title 24 sheets
• Structural plans and calculations — foundation, floor framing, roof framing, seismic bracing
• Topographic survey for hillside lots (average slope over 15%)
• Geotechnical soils report, per the building division's submittal list

Where applications usually get stuck

• Neighbor notification gaps. Unsigned forms or missing mail receipts stall the application before review even starts.
• Hillside and Very High Fire Hazard Severity Zone lots face extra conditions — sprinklers, off-street parking, emergency-vehicle access.
• The geotechnical soils report is a real cost many homeowners don't budget for until the building submittal.
• The 15-day appeal window. Planning decisions can be appealed by affected parties — an approval isn't final until it closes.
• Mismatched details across sheets — equipment model numbers, panel schedules, and utility callouts that don't agree bounce resubmittals.