San Diego distinguishes an accessory dwelling unit (ADU) from a junior accessory dwelling unit (JADU), and it directs property owners to check the applicable use-regulation table. A general statement that a property can have an “ADU” is not enough to establish that a specific unit form or parcel qualifies.

ADU zone and form screen

The City’s Information Bulletin 400 describes an ADU as an attached or detached residential dwelling of no more than 1,200 square feet, with complete independent living facilities, on a lot with a proposed or existing single- or multiple-dwelling use. ADUs are permitted where the applicable use-regulation table identifies them as allowable limited uses. The bulletin points to the base-zone tables in San Diego Municipal Code Chapter 13 and planned-district tables in Chapter 15, and to the City’s Zoning and Parcel Information Portal (ZAPP) for a property’s zone designation.

In a single-dwelling-unit zone, the bulletin lists a primary dwelling, an attached or detached ADU, an ADU converted from existing space or an accessory structure, and a JADU among the described possibilities. A legally permitted, previously conforming multi-dwelling building in a single-dwelling zone can follow a different set of rules. Multiple-dwelling zones have their own provisions.

JADU is a separate classification

San Diego defines a JADU as 150 to 500 square feet within an existing or proposed single dwelling or an attached garage on a residential single-dwelling lot. It may share sanitation facilities with the single dwelling and must provide a kitchen or efficiency kitchen. The City’s table generally places JADUs in single-dwelling zones; a limited exception applies to a legally permitted, previously conforming single dwelling in a multiple-dwelling zone.

Verify the exact parcel and current rules

Use ZAPP to identify the zone, then check the current use table and any planned-district ordinance. San Diego’s bulletin notes that some changes in the Coastal Overlay Zone depend on certification status. Lot conditions, overlays, development standards, building code, and permit requirements remain separate checks. The bulletin is a screening guide, not a parcel determination or building approval.

Confirm the current municipal code and parcel conditions with Development Services before relying on the result. Do not apply San Diego’s ADU/JADU definitions or size limits to another California city.