California's New Laws on ADU's

What homeowners should know about California's 2023 ADU law

This article and website is very helpful in understanding California’s new ADU laws and what has changed in the last two years. As housing gets more and more expensive, it might be time to think about how to utilize your existing investment to create income or to help out the kids.

Constructing an Accessory Dwelling Unit (ADU) in California just became easier with recent updates to statewide ADU laws. New California legislation went into effect on January 1st, 2023 that allows 2-story ADUs in some instances, provides more flexibility in where ADUs can be located on a property, and makes obtaining an ADU permit a more transparent and streamlined process. Learn more about these new laws, below. To understand and visualize how these updated regulations impact your California property, visit Symbium’s Citizen’s Dashboard.

Symbium’s Vision of Government Relationship Management enables any member of the public to understand and visualize property potential with instant regulatory analysis against statewide planning and building regulations, starting with ADUs and other types of home improvement and electrification projects. Homeowners and contractors have been using Symbium to perform initial ADU feasibility assessments on California properties. More recently, a growing number of California real estate agents are using screenshots of Symbium in their listings and on iPads in their open houses to help buyers better understand property potential.

Relaxed Height Restrictions

Before the newest ADU law updates, local governments could limit the height of ADUs to 16 ft. Now, ADUs taller than 16 ft are allowed in certain circumstance, including the following:

  • Detached ADUs can be up to 18 ft high if the property is located within a half-mile of a major transit stop or a high-quality transit corridor, or is located on a property with a multistory multifamily dwelling.
  • Attached ADUs can be up to 25 ft high or as high as the main house, whichever is lower.

Learn more about what height restrictions apply to your property with Symbium.

Building in the Front Setback

Local jurisdictions can no longer deny your ADU application if you encroach into a front setback because there is not enough space elsewhere on the property to build an 800 sq ft ADU. This allows homeowners with very little backyard space to still be able to construct an ADU.

A More Informative Permit Application Review Process

If your permit for an ADU is denied, your local jurisdiction is now required to provide a detailed list of reasons why. This includes specifying which items in the application are “defective or deficient”, as well as a description of what the applicant can do to remedy these comments. Homeowners and contractors will now be able to directly address and avoid future problems with their ADU permit application, making it easier to obtain a building permit for an ADU.

Symbium is your free, one-stop ADU resource!

Learn whether or not an ADU is possible on your property by entering your address with Symbium and navigating to the “Accessory Dwelling Units (ADU)” tool under the “Projects'' tab. Symbium supports you through your ADU decision-making process by allowing you to explore different ADU designs and visualizing how they would look on your property. You can also generate a report on specific ADU types with additional considerations, such as cost estimates and the permitting process. Symbium’s ADU tool will provide instant regulatory analysis against current State and (in some jurisdictions) local regulations, allowing anyone to visualize whether an ADU is allowed along with the applicable development standards. Connect with ADU builders and design professionals on Symbium’s ADU marketplace once you feel ready to take the next steps in getting an ADU built!

Top 4 things anyone can do for free using Symbium

Symbium just released the following short, 2-minute videos on some of our most popular and newest features. Watch them below and learn how to obtain better property insights, apply for permits and rebates, and understand whether an ADU is allowed on any California property.

  • Property Data Insights - Symbium provides valuable property data insights to help homeowners and real estate professionals make informed decisions.
  • Apply for Permits - Applying for a permit has never been easier with Symbium's streamlined application process.
  • Apply for Rebates - Homeowners can save money and reduce their environmental impact by using Symbium to apply for rebates on energy-efficient upgrades.
  • Check Whether an ADU is Allowed on your Property - Homeowners can use Symbium to quickly and easily check whether an ADU is allowed in their area.


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