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Accessory Dwelling Units

An accessory dwelling unit (ADU)—also known as a granny flat or backyard home—is a secondary residential unit on a property with a proposed or existing home. Recent revisions to California State law have made ADUs easier and more affordable to build.

For questions about how to build an ADU or apply for an ADU permit, please visit the ADU page on the Los Angeles Department of Building and Safety website.

ADU Benefits

Homeowners build ADUs for various reasons, including:

  • To generate rental income

  • To increase a property’s resale value and home equity 

  • To create private living spaces for extended family or elderly parents

ADUs benefit communities by adding more housing units while maintaining the character of a neighborhood. ADUs are more affordable to build than other types of housing, such as single-family homes, because they do not require buying new land.

ADU Laws and Regulations

Since 2017, California State lawmakers have passed multiple bills to make it easier for homeowners to build ADUs. Five bills made effective on January 1, 2020 have significantly streamlined the ADU construction and approval process. These bills and their key provisions include: 

AB 68 and AB 881: 

  • Require permits for ADUs and Junior ADUs (JADU) to be approved or denied within 60 days, rather than the 120 days allotted by previous law

    • A Junior ADU (JADU) is an ADU of no more than 500 square feet. A JADU must be within a proposed or existing single-family home or accessory structure, such as a garage. Unlike ADUs, JADUs may share a bathroom with the single-family home and must only meet “efficiency kitchen” requirements.

  • Prohibit application of development standards that limit size (including floor area ratio, open space, and minimum lot size) if it prohibits the construction of at least an 800 square foot ADU that meets other criteria

  • Limit local discretion in establishing minimum and maximum unit size requirements

  • Allow for up to one ADU and one JADU on any residential property

  • Allow for multiple ADUs within an existing multi-family dwelling or up to two detached ADUs on a multi-family property

  • Remove parking replacement requirements when an ADU results in the demolition or conversion of existing parking 

SB 13: 

  • Allows an ADU to be built in the same location and physical dimensions as an existing accessory building that is demolished to provide an ADU, along with an 150 square feet addition, if provided for ingress/egress  

  • Prohibits owner-occupancy requirements until 2025

  • Eliminates impact fees for ADUs under 750 square feet and requires fees to be proportional to the square footage of the primary residence

AB 670 and AB 671:

  • Prevent homeowners’ associations from barring ADU construction on single-family properties or imposing reasonable restrictions

  • Require local housing agencies to incentivize and promote the construction of ADUs that can be offered at affordable rental rates to very low, low-, or moderate-income households

The official ordinance for the City of Los Angeles can be found here
Please visit the ADU page on the Los Angeles Department of Building and Safety website for more information on how to build an ADU and submit your building plans.

Types of ADUs

Homeowners can build many different types of ADUs. ADUs can be attached or detached from the existing home, or located within the existing home. 

ADU images courtesy of Office42 Architecture, Duvivier Architects, and Connect Homes.

Image of an ADU
Image of an ADU


Image of an ADU
Garage Conversion Graphic

A converted former garage.  

Home Conversion Graphic

A converted area of the primary home, with its own kitchen and bathroom. 

New Detached ADU Graphic

A new independent structure, separated from the primary home and often placed in the backyard.

Garage Addition Graphic

A new unit that shares at least one wall with the garage. Units can be built above the garage.  

Home Addition Adu Graphic

A unit that shares at least one wall with the primary home. 

Junior Adu (JADU) Graphic

An ADU of no more than 500 square feet that can be built within a proposed or existing single-family home or accessory structure.