San Diego ADU Guideline

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Real Estate


 The city government of San Diego has updated its local zoning codes to comply with the State ADU mandate.
 The California Building Code (CBC) 2019 is adopted.
 Relevant state bill updates for SB13, AB68, AB881, AB670 are shown in green below.



City Hint: In The City of San Diego, permitting fees for ADUs have been reduced recently due to a new waiver program to incentivize housing development in the city.

City Hint: The city has not yet responded to requests for ADU permit volumes for the past year, but they will be provided here once response has been received.


Number of ADUs allowed:

According to state law, all single-family homes are allowed at least one Accessory Dwelling Unit (ADU). Additionally, single-family properties which are owner-occupied may create one Accessory Dwelling Unit (ADU) and one Junior Accessort Dwelling Unit (JADU). Also, multi-family properties may now add one ADU per every four existing residential units, so long as they were legally established.


As of January 1st, 2020
Types of ADUs allowed:

Detached ADU, Attached ADU, Junior ADU are approved. ADUs may be new construction or converted from existing space. JADUs must be converted from existing space.

Lot size:

Accessory Dwelling Unit (ADU) projects on single family or multi-family residential lots will not be subject to the minimum lot size of the underlying local zoning code or by special ordinance. ~ AB-68


As of January 1st, 2020
ADU size:

Single-family and multi-family Lots will be permitted to build up to 850 sq. ft. for a one bed ADU or up to 1,000 sq. ft. for a two bed ADU, regardless of the underlying zoning standards of the property. A Junior ADU up to 500 sq. ft. is permitted. The minimum size of any living unit (including Accessory Dwelling Units and Junior ADUs) is 150 sq. ft. according to Califronia Residential Code. ~ AB68 & AB881 Update


As of January 1st, 2020

Setbacks for a detached new construction Accessory Dwelling Unit (ADU) shall be no more than 4 feet from the rear and side lot lines. No setbacks shall be required for Accessory Dwelling Unit (ADU)s and Junior Accessory Dwelling Units converted from legally eastablished existing space. Attached new construction Accessory Dwelling Unit (ADU)s and conversions from existing space to be expanded must comply with the setbacks of the underlying zone. ~ AB68


As of January 1st, 2020

Parcels which convert an existing garage to an Accessory Dwelling Unit or Junior Accessory Dwelling Unit will not be subject to replacement parking requirements. ~ AB68 & AB881 Update


As of January 1st, 2020
Fire Safety:

The ADU shall only be required to have fire sprinklers if they are required in the primary dwelling.

Shape, materials and style:

The ADU shall resemble the architectural design characteristics of the primary dwelling, including but not limited to, paint color, windows, roof pitch and massing.


For ADUs located above a garage or other accessory building: The maximum structure height for flat-roofed structures is 21 feet; and The maximum structure height for sloped-roofed structures with a roof pitch of at least 3:12 (3 vertical feet to 12 horizontal feet). For detached ADUs, not above a garage or other accessory building: Max is 15 feet without a chimney or flue, or 17 feet with a chimney or flue.

Design review:

You must apply for a building permit. Please refer to the Project Submittal Manual, Section 2A, for all general requirements related to the submittal process.

A. Typical Submittal Documents Minimum submittal requirements for each companion or junior unit proposal includes the following
(per Project Submittal Manual, Section 2A):

1. Plans / Calculations:
(a.) Site Plan and Vicinity Map (See Information Bulletin 122).
(b.) Floor Plans and Roof Plans.
(c.) Elevations and Sections (as applicable).
(d.) Structural plans and details.
(e.) Structural calculations and/or truss calculations (as applicable).
(f.) Title 24 Energy calculations.

2. Forms.
(a.) General Application, DS-3032.
(b.) Water Meter Data card, DS-16.
(c.) Storm Water Applicability Checklist, DS-560 (not required for a Junior Unit).

*** According to state law, ADUs must be provided a ministerial review process. This requires that a proposed ADU which complies with all state and local standards should be approved within no greater than 120 days from the date of submission, or else that ADU should be approved automatically.

Number of Bedrooms:
Not specified by State Standards.



Owner-occupancy will not be required for new Accessory Dwelling Unit (ADU)s (conversion and new construction) built between 2020 and 2025. ~ SB13


As of January 1st, 2020
Utility connections:
Local health officer approval where a private sewage disposal system is being used, if required. (State requirements)
Permit Fees
SB13 Update: As of January 1st, 2020, local impact fees for ADUs will be reduced substantially statewide.
Historic Requirements:

If the property is located in a potentially historic district the project will be required to be reviewed historic compliance.

Coastal Areas

Within the Coastal Overlay Zone, companion units are subject to the provisions of Chapter 12, Article 6, Division 7. If inside the costal overlay, the project will be required to be reviewed for compliance prior to issuance of a building permit.


Companion unit entrances shall not be located on the building street wall or within the front 50 percent of the structure. The companion unit must have a separate entryway from the main dwelling.

Allowed Zones:

*** Beginning in 2020, according to state law, all residential zoning districts, including single-family and multi-family, are allowed to build Accessory Dwelling Units. ***

1. Permitted as a limited use in residential zones.
2. Permitted as a limited use in multiple dwelling unit residential zones where the maximum allowable density is two units based on the existing lot area.
3. Within the Coastal Overlay Zone, a Coastal Development Permit is required for a companion unit.


As of January 1st, 2020
Floor Area Ratio

The gross floor area of the companion unit shall be included in the floor area ratio calculation for the premises.


One 24-inch box tree shall be planted in the required front yard of the premises or in the abutting parkway. Existing trees that are at least 15 feet high and 15 feet in width may be used to satisfy this requirement.

Residential Building Code:

The California Building Code (CBC) 2019 is adopted.