2023 Guide to California ADU Laws

A prefabricated ADU by Abodu being installed.

A prefabricated ADU by Abodu being installed.


August 1, 2023ADU Law

California is working hard to make ADUs more accessible for all of its residents and create more liveable space. Learn more about California’s new accessory dwelling unit laws that went into effect in 2023 and how they affect California homeowners.

What are the new laws for ADUs in California 2023

California continues to pass new laws that make installing an ADU easier and more accessible for homeowners, here’s a summary of the laws that passed in 2023.

Height restrictions have been relaxed

Previously, homeowners were restricted to building their ADUs to a max height of 16 feet. In 2023, height restrictions statewide have been relaxed and in certain circumstances can now be built higher than 16 feet.

  • Attached ADUs: can be up to 25 feet or as tall as the main house, whichever is lower.
  • ADUs within a ½ mile of public transit: up to 18 feet.
  • Property with a multi-family dwelling that is two stories: up to 18 feet.

A more transparent 60 day rule

Beginning in 2020 permitting offices were required to approve or deny your ADU permit within 60 days. However, because of the significant increase of applications, many permitting offices were simply denying the application once the 60 day limit was up.

This change to the 60 day rule means that if your permit is denied, your permitting agency must provide a detailed list of reasons why, including specifying what parts of your application are deficient. They also must include a description of how you can remedy the deficiencies.

This change makes it much more difficult for local agencies to simply deny your permit and requires them to do the extra work of helping you understand how to fix your application.

Better-defined front setback

In 2023, if an 800 square foot ADU encroaches on the front setback, your local jurisdiction can no longer deny your ADU application, which helps homeowners that have limited backyard space add an ADU to their property.

What other laws are important for ADUs in California?

Beyond the bigger legislative changes outlined above, there are a few more laws that also impact ADUs.

Unpermitted work

Many jurisdictions have prevented homeowners from building ADUs if there is unpermitted work on their property.

A 2023 change in legislation eliminates restrictions to build an ADU if you have unpermitted work on your property, unless it’s deemed a health and safety hazard. Unpermitted work can include: non-conforming zoning conditions, building code violations or unpermitted structures.

Fire sprinklers

Previously homeowners were required to install fire sprinklers into their primary residence when they built an ADU. This recent 2023 change eliminates mandatory fire sprinklers in the primary ADU.

JADU bathrooms

Homeowners no longer need to include a bathroom in an attached JADU (junior accessory dwelling unit) so long as the bathroom in the primary residence is accessible to the JADU.

Changes to demolition laws

Some cities were previously blocking ADU construction that involved demolition (like a garage conversion) by permitting the ADU but then withholding the demolition permit needed to tear down existing structures. This effectively halts the ADU construction. Now in 2023, cities can no longer withhold demolition permits if an ADU permit has been issued.

CalHFA working group

The $40k CalHFA grant is an amazing funding resource for homeowners that want to build an ADU. A new law will now require CalHFA to have a working group that develops recommendations for making it easier for homeowners to qualify for ADU construction loans. The law will also increase access to capital available to qualifying homeowners.

An Abodu One in San Jose.

An Abodu One in San Jose.

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