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ADU Permits in Vallejo: a Homeowner's Guide
The 800 sq ft shortcut, the Central Permit Center, and the separate address step — how Vallejo's ADU process works, in plain language.
Last updated October 2026. Rules change; always confirm current requirements with the city before you build.
Who handles your permit
In Vallejo, ADU permits run through the Central Permit Center at 555 Santa Clara Street, Vallejo, CA 94590 — in person or through eTRAKiT. Planning can be reached at (707) 648-4326 and Building at (707) 648-4374, or by email at planning@cityofvallejo.net. The key fork: ADUs of 800 sq ft or less go straight to a building permit; anything over 800 needs Planning Division approval first.
What you can build
1,200 sq ftMax for a detached ADU under state law
800 sq ftAt or below this, skip Planning and go straight to a building permit
16 ftHeight limit for most detached ADUs
4 ftMinimum side and rear setbacks, detached ADUs
1 + 1One ADU plus one Junior ADU per single-family lot
60 daysState deadline to act on a complete application
Vallejo-specific things to know
- The 800 sq ft fork. This is Vallejo's most important number. An 800 sq ft ADU goes straight to building permit; 801 means a Planning Division stop first. Design to the line intentionally.
- Separate address. Vallejo ADUs get their own address through Public Works at (707) 648-4315 — a step that's easy to forget and needed for utilities and mail.
- Older infrastructure. Vallejo's housing stock is old, and service upgrades (electrical, sewer) are the usual budget movers.
- Solano ADU resources. The county's Solano ADU website publishes homeowner resources — a useful supplement to the city's own pages.
Get the address step on the calendar. The separate Public Works address assignment isn't on the permit checklist, so it's the classic afterthought — and everything downstream (utilities, occupancy) waits on it.
What goes into the submittal
- Building permit application (eTRAKiT or in person at the Central Permit Center)
- Planning Division application first, if the ADU exceeds 800 sq ft
- Site plan: lot lines, structures, setbacks, easements, utilities, drainage
- Architectural plans: floor plans, elevations, sections
- Structural plans and calculations, Title 24 energy documents
Where applications usually get stuck
- The 800 sq ft fork. Starting Planning when the design was already at 800, or skipping it at 850 — check the math before filing.
- Service capacity. Older Vallejo panels and sewer laterals are the most common correction-round topics.
- Flood and shoreline overlays. Low-lying and waterfront-adjacent parcels can carry additional review.
- Corrections cycles. As everywhere, complete first submittals are the cheapest way to shorten the timeline.
Not sure where to start? That's the part we do. We check your parcel against Vallejo's 800 sq ft fork, prepare the right submittal for the right division, and manage corrections — one point of contact.