ADU Permit Requirements in San Diego (2026 Guide)
California and San Diego have made ADUs far easier to permit. Most single-family and many multifamily lots can add an ADU, and often a junior ADU, subject to size, setback, and building-code rules. A licensed contractor handles plans, permitting, and inspections.
Types of ADUs you can build
An Accessory Dwelling Unit (ADU) is a self-contained living space on a residential property. San Diego allows several types:
- Detached ADU — a standalone structure in the yard.
- Attached ADU — added onto the existing home.
- Garage or interior conversion — converting existing space into a unit.
- Junior ADU (JADU) — a smaller unit (up to 500 sq ft) within the existing home, often sharing some facilities.
The ADU approval process
State law has streamlined ADU approvals and shortened review timelines. At a high level the process is:
- Design plans and a site plan that meet zoning, setback, and size limits.
- Submit for plan check / building permit with the local jurisdiction.
- Address plan-check comments; obtain the permit.
- Build with required inspections at each phase.
- Final inspection and certificate of occupancy.
Important caveats
ADU rules depend on your exact lot, zoning, jurisdiction (City of San Diego vs. county vs. other cities), utilities, and fire-access requirements, and they change over time. This is a general overview, not legal or code advice. The most reliable path is a consultation where we review your specific property and current local requirements, then handle plans, permitting, and construction end to end.
Planning a adu construction project in San Diego?
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Frequently Asked Questions
Yes. ADUs require building permits and inspections. California and San Diego have streamlined the process, but you still need approved plans that meet zoning, setback, size, and building-code requirements. A licensed contractor manages permitting and inspections for you.
Permitting timelines have been shortened by state law, but vary by jurisdiction. Including design, permitting, and construction, most ADUs take several months end to end. We manage the full process.
In most cases, yes. San Diego permits ADUs on most residential lots with an existing single-family home, and often a junior ADU as well, subject to size and setback rules for your specific property.
