Build an ADU in San Diego, California

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Overview

San Diego is located in San Diego County in California. San Diego has a total
population of 1301617 over a land mass of 325.19 Square Miles. When it comes to
ADUs, the city allows for 1+ ADUs on a given property, and a square footage of
850-1,000 sf

Number of ADUs Allowed

1+

Size of ADU Allowed

850-1,000 sf

Types of ADUs Allowed

Detached, Junior, Attached

Permit Cost

Coming Soon

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.

Property Requirements

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

Types of ADUs Allowed

Attached ADU

An attached ADU is one that is attached to your house. Also know as Addition ADUs or “bump-out ADUs. These types of ADUs can be accessed from the primary house with a door in the connection point, but also can be independent of the main home.

Detached ADU

A detached ADU is not connected to your primary house. The dwelling needs to be within your property setbacks and allowable building size (both height and square footage).

Junior ADU

Junior Accessory Dwelling Units (JADUs) are named this way because they are small (up to 500 square feet).

In California, the recent state bills AB68 and AB 881 permits both an ADU and a Junior ADU (JADU) on the same lot with a proposed or existing single-family dwelling. This means you can have two units on your lot: ADU, and JADU.

Property Requirements

Ownership
Owner-occupancy will not be required for new Accessory Dwelling Unit (ADU)s
(conversion and new construction) built between 2020 and 2025. ~ SB13
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.
ADU 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
Parking
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
Height
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.
Fire Safety
The ADU shall only be required to have fire sprinklers if they are required in
the primary dwelling.
Utility Connections
Local health officer approval where a private sewage disposal system is being
used, if required. (State requirements)
Aesthetic
The ADU shall resemble the architectural design characteristics of the primary
dwelling, including but not limited to, paint color, windows, roof pitch and
massing.
Set backs
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

Design Review

PERMIT APPLICATION PROCESS: 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.

Next Steps

To get started on your ADU, here are some first steps.

Call Your City

Search Google for your city’s contact number. eg “City of {Phoenix} Residential Permits Contact Number”

You can call the main line and get directed to the permitting department.

Ask these questions...

1) Can I put a secondary home on my lot (Accessory Dwelling Unit)?
2) What are my livable setbacks, and ADU size regulations?
3) Can I put a prefabricated guest house on my property?

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