What is a deferred submittal, and which ADU items can be deferred?

A deferred submittal is a portion of the design that is submitted after the main permit application, with the building official's prior approval. San Diego's bulletin on deferred submittals lists fire sprinkler systems, fire alarm systems, floor and roof trusses, solar photovoltaic systems and EV charging stations among the items that can be deferred for all building types. Each deferred item still needs its own review and approval before it is installed.

How deferral works

San Diego's Information Bulletin 188 (February 2026) is a clear example:

• Deferral of any submittal item needs the building official's prior approval, and the architect or engineer of record in responsible charge lists the deferred items on the construction documents.
• Except for fire alarm and fire sprinkler items, deferred documents cannot be submitted until the building permit is issued. To submit them earlier, add them to the main permit instead.
• Deferred documents must include a statement by the architect or engineer of record that they were reviewed and found in general conformance with the building design.
• Submit at least 30 business days before installation, and do not install until the documents are approved.
• Deferred items follow the codes under which the building was permitted.
• Where solar PV or EV charging is required, it can be deferred; optional systems go on separate stand-alone permits.
• For trusses, the main set must include a framing plan showing the truss layout and design loads, stamped by the design professional of record.

ADU items that often come up

• Fire sprinklers. HCD's ADU Handbook says fire sprinklers can be required in an ADU only when they are required for the existing primary residence. Santa Barbara's pre-approved ADU program has sprinkler drawings submitted on a separate permit.
• Solar PV. Where the Energy Code requires PV for a new ADU, a department may allow the PV design to follow the main permit.
• Trusses. Truss calculations may be deferred where allowed, but the layout and loads still belong in the main set.

Not every department allows the same items, so check before you plan on deferring anything.

Why deferral affects MEP plans

• A deferred PV system still needs panel space and a conduit path, so the electrical plan should anticipate it.
• Fire sprinklers draw from the water service shown on the plumbing plan, so service sizing should be coordinated early.
• Truss layouts affect where ducts, fans and line sets can run.

What this means for your MEP plans

Tell your MEP designer which items will be deferred so the main set leaves room for them and nothing has to be torn out later. See fire sprinklers in ADUs, solar requirements and solar on electrical plans. Deferral lists differ by jurisdiction, so confirm with your building department.

Sources: sandiego.gov, hcd.ca.gov, santabarbaraca.gov.