Policy Updates & Our Positions

As of January 30, 2020. Subject to change.

Background: Accessory Dwelling Units are not a new idea, but they are known by many names. Detached new construction ADUs are sometimes called backyard cottages, granny flats, laneway houses, or DADUs. ADU’s can also be built above a garage or workshop. These are often called garage apartments or carriage houses. Attached ADUs are typically created by building an addition to or converting a portion of an existing single family home. These are commonly called basement apartments, in-law units, secondary suites, or English basements.


What ADUs have in common? While their structural forms vary, ADUs share some common traits and face common design and development challenges. For one thing, the fact that they’re secondary housing units on single family residentially zoned lots places ADUs into a unique category of housing. And ADUs also have some other distinguishing characteristics that help further define, differentiate, and distinguish them from other housing types.

  • An ADU is an additional rentable housing unit that is accessory to the primary dwelling

  • ADUs vary in size from a 150 sq. ft. studio to 1,200 sq. ft. 3 bed, 2 bath +

  • ADUs can be built simultaneously with a primary dwelling or any time after

  • California state ADU laws have progressively increased opportunities by creating standards that apply to all California homeowners

  • Each Jurisdiction can implement some additional control through a local ordinance, but with the new laws that just went into effect, the local standards of previous years have been reset.

These different characteristics make ADUs a distinct type of housing. Until now, there has been a lack of common understanding around the language and best practices of ADU development.

California ADU Laws

It is now easier, faster, and cheaper to build and ADU in California than ever before.

The new state laws greatly improve the process of getting an ADU approved. Homeowners have many more options available to them. Lower application fees allow for resources to be allocated for good design.


The 2017 legislation (SB1069 & AB2299) re-set state laws and opened opportunities for ADUs or Companion Units as they are known in San Diego. 


In 2017 and through 2018, most cities throughout the state came up with ADU ordinances to address the changes in state law. Some were good. Some were bad, and some were just blatant attempts to restrict growth by exploiting loopholes. An effort was made in 2018 to clean up the bills. The changes were minor with cities arguing for more time to comply.


The 2019 legislation (AB68, AB881, AB670, and SB13) intended to close loopholes and make it easier to for homeowners to positively impact our housing crisis. The laws made all previous legislation on ADUs null and void.


The most impactful changes to ADU regulations effective January 1 2020 are:

  • Cities can no longer require owners to live in one of the units (no owner/occupancy requirements)

  • Cities have fewer obstructions they can use to restrict where ADUs can be built.

  • Cities have fewer standards they can impose on ADU development.

  • Cities have to 60 days to approve and permit ADUs.

  • ADUs up to 750 sq. ft. cannot be charged impact fees. This includes school fees.

  • HOAs and PUDs can no longer prohibit ADUs and must also follow the guidelines set for cities

  • Approvals for ADUs are not at the discretion of jurisdictions; They are ministerial, or allowed by right.


  • New opportunities to add ADUs to both single family, and multi-family properties.

  • New opportunities to add ADUs and JADUs (bedroom conversion) to single family properties

  • New opportunities to add more than one ADU on multi family properties in specific situations


  • Most importantly, Homeowners are no longer alone in fights with cities ignoring state law. The Department of Housing and Community Development now has the responsibility of enforcing and interpreting the state law.

ADU Coalition © 2020  

A committee of the San Diego
American Institute of Architects

a non-profit 501(C) organization

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