Permits & process
How long does it take to get an ADU permit in San Mateo?
San Mateo ADU permits take 12–22 weeks elapsed in 2026. State law requires ministerial review within 60 days of a complete application, but corrections cycles, utility sign-offs, and overlay reviews (hillside, fire, historic) typically add 4–8 weeks.
San Mateo accepts electronic submittal through its building department portal. Concurrent submittal of building, electrical, plumbing, and mechanical disciplines is faster than sequential.
Pre-application meetings with planning and building staff are free in most California cities and surface issues before formal submittal — typically saving 3–6 weeks of corrections.
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Related questions
- • What's the San Mateo ADU fee schedule?
- • Can I speed up San Mateo ADU permitting?
- • Does San Mateo accept pre-approved ADU plans?
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