STATEWIDE UPDATE: New California ADU Bills SB13, AB68, AB881, AB670 have passed. These laws will create more options for building an ADU in San Diego in 2020. To prepare for the upcoming changes use our ADU Services to learn how these laws will affect your property!
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San Diego ADU Guidelines Last Updated 12/05/19


The city government of San Diego has updated its local zoning codes to comply with the State ADU mandate.
The California Building Code (CBC) 2016 is adopted with the following amendment(s): O-20896NS & O-20897NS
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:

No more than one ADU is permitted on a property.

AB68 & AB881 Update: Properties which convert existing space to create ADUs may be eligible for one ADU -AND- one JADU.

Types of ADUs allowed:

An ADU may be attached to or detached from the primary dwelling unit on the property. Junior ADUs may also be permitted.

Lot size:

The minimum lot size for an ADU is determined by the maximum density of the underlying zone.

AB68 & AB881 Update: Properties will not be subject to minimum lot standards by ordinance or of the applicable zoning district.

ADU size:

ADU Size: 1. An attached companion unit shall not exceed 50 percent of the existing habitable area of the primary dwelling unit, up to a maximum of 1,200 square feet. A detached dwelling unit is permitted up to a maximum of 1,200 square feet. 2. Installation of a fire sprinkler system shall not be required for new Companion Units or Junior Units, as defined in the SDMC (and stated per 2016 California Senate Bill 1069 as Accessory Dwelling Units) that are 1,200 sq. ft. or less in area when located on the same lot as an existing non-sprinklered dwelling unit. Junior ADU Size: 1. Maximum of 500 square feet. 2. Installation of a fire sprinkler system shall not be required for a Junior Unit when located within an existing, non-sprinklered dwelling unit.

AB68 & AB881 Update: Properties will be allowed up to 850 square feet for a one bedroom or up to 1,000 square feet for a two bedroom ADU.


ADU Setbacks: 1.) An existing permitted garage or non-habitable accessory structure within setbacks may be converted, subject to California Building Code. 2.) A companion unit may encroach within the side and rear yards as follows: (a.) A one story structure, up to a maximum encroachment of 30 feet in length. (b.) A second story, if constructed above an existing permitted garage or non-habitable accessory structure.

AB68 & AB881 Update: The maximum required setback for a detached new construction ADU shall be no more than 4 feet from the rear or side property lines.


ADU Parking Required:
1. One parking space is required, unless one of the following conditions is met:
(a.) Unit is 500 square feet or less.
(b.) Site is within the Transit Area or Transit Priority Area.
(c.) Site is within a historical designated area.
(d.) Site is located within a residential parking district.
(e.) Site is located within one block of a car or bike share station.
2. The conversion or demolition of a garage requires replacement parking, in addition to the one required space. The parking may be placed within setbacks or in a tandem configuration.

AB68 & AB881 Update: Properties which convert an existing garage will not be subject to replacement parking requirements.

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.


1. A companion unit may not be sold or conveyed separately from the main dwelling unit.
2. The owner does not need to live in the primary dwelling unit nor companion unit and both can be rented. A companion unit cannot be used for a rental term of less than 30 consecutive days.
3. Only one Companion Unit is allowed on a premises. A Junior Unit is not allowed on a site with a Companion Unit. Guest Quarters and non-habitable structures are permitted on the same premises.

*** Before a Building Permit may be issued for an ADU, the record owner shall enter into an agreement with the City in a form that is acceptable to the City Attorney. The agreement shall include the following provisions: that neither the primary dwelling unit nor the ADU may be sold or conveyed separately and that the record owner shall reside in the primary dwelling unit or the ADU. The City will submit the agreement to the County Recorder for recordation. The agreement shall run with the land and be coterminous with the life of the ADU.

SB13 Update: Owner-occupancy requirements for ADUs will be voided statewide for 5 years.

Utility connections:

Local health officer approval where a private sewage disposal system is being used, if required. (State requirements)

Permit Fees

SB13 Update: 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:

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.

AB68 & AB881 Update: ADUs will be allowed statewide in all single-family or multi-family zoning districts.

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) 2016 is adopted with the following amendment(s): O-20896NS & O-20897NS

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* upon completion of ADU


* based on local average price per sqft


* estimated by location


* 30 years / 5% interest rate / 20% down payment


Appreciation Estimate = (Base Value: $) / (Home's Living Space: sqft) * (ADU's Living Space: sqft)

Rental Estimate = (Rent Per Sqft: $3.27) * (ADU's Living Space: sqft)

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