California ADU Laws to Know in 2025

A Brief History of California ADU Rules

In order to understand the current state of California’s ADU rules, it’s helpful to understand how much things have changed in the last 10 years. Prior to 2016, while localities were encouraged to allow ADUs on single-family lots, local governments had wide-ranging authority to restrict development. Many did, creating a situation whereby residents were forced to navigate an extraordinarily difficult environment with vastly differing rules on a town-by-town (or even neighborhood) basis – not an ideal situation for a state facing a massive housing crisis that remains ongoing even today.

2016 – Major Changes in California ADU Laws

While a few state bills were passed to try and alleviate this problem, it wasn’t until 2016, when a comprehensive suite of ADU Law reforms was passed, that homeowners finally had a consistent, cohesive framework in place that allowed the “ADU Revolution” to truly begin. 

This package of new ADU rules included:

• ‍SB 1069, which significantly reduced parking requirements for ADUs, including eliminating them in some cases, such as for units near public transit, and also restricted (and in some cases prohibited) utility connection fees and capacity charges that cities could levy on ADUs. The law also prohibited cities from requiring sprinklers in an ADU if they were not also required in the primary residence.
• ‍AB 2299, which, perhaps even more importantly, established that any local ordinance inconsistent with the new state laws would be null and void, creating one comprehensive set of rules statewide.

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2019-2022 – Expanding and Refining ADU Access for Homeowners

As a result of the 2016 changes, ADUs enjoyed explosive growth throughout California in the years following, setting the stage for the next phase of ADU acceptance, but more clarification was still needed. The next round of California ADU law updates addressed additional areas of local concern.

• ‍AB 68 and AB 881 allowed for up to two units – one ADU and one Junior Accessory Dwelling Unit (JADU) – on a residential lot, prevented homeowners' associations (HOAs) from banning ADUs, and also addressed reassignment & redevelopment of existing spaces (like garages) into ADUs.
• ‍SB13 eliminated owner-occupancy requirements for ADUs through 2025 (now made permanent), and in 2020, AB 3182 established an automatic approval process if a local agency failed to make a decision within 60 days. 

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2023-2025 – The Newest California ADU Laws

Under a series of new state laws that took effect on January 1, 2025, ADUs are now easier to build in California than ever before. In the most recent round of legislation, California's Accessory Dwelling Unit (ADU) laws eliminate owner-occupancy requirements (except for JADUs) (AB 976), expand ADUs for multifamily properties (up to eight, or one per existing unit - SB 1211), and provide a path to legalization of previously unpermitted ADUs (AB 2533) without significant penalties. Additionally, new laws relax setback requirements, increase height limits (up to 25 feet in some cases), require pre-approved ADU plans to speed up permitting and create a 30-day timeframe for local governments to approve or deny permits on these units (AB 1332). Finally, an existing general outline for selling ADUs as separate condominium units (AB 1033, passed in 2023) may create significant financial and housing flexibility for existing and prospective California homeowners if widely adopted by local governments going forward.

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Wellmade is Ready to Guide you Through the ADU process‍

Today, California homeowners are more likely to get a speedier approval, but also now have more options with designing and citing an ADU on their property. Nevertheless, while new laws continue to expand the options and eliminate obstacles toward designing and building ADUs, it can still be a complicated process. Many of the rules noted above modify, change, eliminate or codify earlier rules, and the laws and codes governing California ADUs are constantly changing. And while this summary provides a basic outline, every project is different, and our brief list of rules and changes cannot account for every municipality, and local rules can still impact ADU design and construction. At Wellmade, our process is designed to help you on every step of your ADU journey. If you’re ready to begin the process of transforming your backyard space with an ADU, or even if you just have questions about what may or may not be allowed where you live, just let us know – we’re excited to be your guide as you make your home better than you ever expected it to be!

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