Take a deep dive into the latest developments in Accessory Dwelling Unit (ADU) laws in 2025. In this blog post, we shed some light on the ins and outs of the latest regulations, guiding contractors , homeowners and real estate enthusiasts through the changes. From zoning updates to permitting requirements, we unravel everything you need to know to navigate the evolving ADU landscape.

It’s important to stay informed to help with decision-making as there are certain implications and opportunities presented by the new ADU laws from 2025. Read on to discover valuable insights so that you can understand and comply with the legal framework.

ADU Law Changes For 2025: What’s New?

The new ADU laws in California in 2025, for example, aim to make it easier and more accessible to install an Accessory Dwelling Unit on a property. Here are the basic updates:

• Relaxed height restrictions: ADUs can now be built higher than 16 feet, up to a maximum of 25 feet.
• Changes to the 60-day rule: There will now be greater transparency about the 60-day rule.
• Better-defined front setback: Under the new rules, if an 800 square foot ADU encroaches on the front setback, this is no longer a basis for denying an ADU application.

These will be welcome changes for many in the state. The 60-day rule was a particular bone of contention, as permitting offices had been frequently denying applications after 60 days with no communication. Now, they must provide a detailed explanation and recommendations to remedy the issues.

It will be important to get an in-depth understanding of the existing ADU rules, as well as these recent changes, to understand the intricacies of ADUs in California from 2025. Read on for more in-depth explanation and analysis.

As of January 2025, there will be three additional bills in California that come into effect. They relate to the legalizing unpermitted ADUs and JADUs, rules around replacement parking spaces, ADUs on multifamily lots, and permits for ADUs within the Coastal Zone. As with the bills that passed in 2023, these new regulations are intended to make it simpler for California residents to build new ADUs as part of a drive to address the state’s housing crisis.

How Do The New 2025 ADU Laws Impact Owners And Builders?

The new ADU bills in California that come into force in 2025 aim to expand housing options, which provides benefits to homeowners, developers, and renters alike. Let’s look at the impact these ADU laws will have:

• Homeowners: Expect greater flexibility. AB 2533 simplifies the process of legalizing unpermitted ADUs built before 2020, helping to enhance property value whilst boosting safety compliance. SB 1211 will allow new opportunities on multifamily lots, as up to 8 ADUs may be permitted in certain cases, and replacement parking mandates will be removed.
• Developers: The benefits for homeowners will extend to developers as well. Plus, with clearer guidelines, particularly around Coastal Zones, it will be easier for developers to build ADUs near high-demand areas. SB 1077 will reduce uncertainty and potentially accelerate project timelines.
• Renters: Expect to see more affordable rental opportunities arise after January 2025 as these policies incentivize more ADU construction. It is hoped that this move will broaden housing supply.

What Actually Are ADU Laws In California Exactly?

ADU laws in California are regulations and legislation governing the construction and use of Accessory Dwelling Units. Commonly labeled ‘granny flats’, these buildings had long been available only as rentals in California. They come in all shapes and sizes – they could be a converted garage, a small home in the backyard or, as often seen in the Contra Costa housing market, an unused portion of the main house.

The existing laws around these constructions had long been criticized for being overly restrictive and unclear. Demand for reform in the legislation has led to the signing into law of Assembly Bills 976, 1033, and 2221 to change the ADU landscape in the Golden State. As of January 2025, we will also see AB 2533, SB 1211, and SB 1077 come into effect.

(For additional information on recent ADU legislation, see our legal alerts covering SB 477, AB 2221 and SB 897, and AB 345. And, in September 2024, Governor Newsom signed three more ADU bills (AB 2533, SB 1211, and SB 1077) that each took effect on January 1, 2025.)

Now, residents all around California have more freedom regarding what they can do with these properties. Instead of merely renting them out, owners are now given the freedom to sell them, and the rules around how they are constructed have been loosened and made more transparent. The new California ADU laws of 2025 are a welcome change for existing homeowners and prospective buyers looking to enter the California housing market.

Specific Assembly Bills Impacting ADU Laws In 2025

AB 976 permanently extends the ability of property owners to construct affordable rental ADUs. These provisions had been in place as of 2020, but were due to expire in 2025. The new California ADU law has now made this a permanent provision, and new ADUs can even be built on the same property as existing rentals. Now, as of 2025, we will also see SB 1211 boost the number of ADUs permitted on multifamily lots up to 8 in some cases, further increasing flexibility for homeowners and developers.

In a more significant development, the signing into law of AB 1033 drastically changes California’s ADU laws. Under the new legislation, ADUs can be built and sold as condominiums, with the hope of providing more freedoms for property owners and making home ownership a more accessible prospect for many. The new constructions must be approved through all the proper channels, and they may be subject to a separate property tax for specific California counties.

This is a leap forward in the ADU landscape in California, as these properties had only been available as rentals before. It is hoped that this move will help supplement the income of retirees and offer young families affordable starter homes.

Are HOA Limitations On ADUs Still Valid In 2025?

• Legislative shifts now reduce some HOA restrictions on ADU development, which is highly relevant for homeowners in HOA-governed areas.

While HOA limitations on ADUs in California will still exist in 2025, there will be some important changes. There will be less scope for Homeowners’ Associations to restrict ADU development due to the following key adjustments:

• Eased restrictions: HOAs are required to permit the construction of ADUs, though they can still regulate architectural standards, placement, and certain aesthetic aspects.
• Owner-occupancy requirements: As of 2025, there will be no mandatory owner-occupancy for ADUs, further limiting HOA influence on usage. Owner-occupancy requirements will still apply to JADUs, however.
• Local regulations: HOA can no longer enforce policies that are more restrictive than state laws. But they may still retain control over usage, such as prohibiting short-term rentals.

How Ab 2221 Alters California’s ADU Regulations

In 2025, AB 2221 streamlined California ADU law, facilitating easier construction, especially in unused commercial spaces. Previously, developers faced limitations, unable to include ADUs in plans for proposed multifamily buildings. The law’s enactment allows builders to seamlessly propose and construct ADUs in new multifamily housing plans, eliminating the need for post-completion adjustments.

The bill also brings some technical changes that reduce arbitrary decisions blocking ABUs. Previously, there were problematic terms like:

• Front setbacks
• Permitting agency

These were often abused as reasons to block ADU construction, but front setbacks are no longer a reason to preclude construction. Moreover, permitting agencies must now return detailed comments on proposed ADUs within 60 days and make suggestions for improvements to be granted permission.

This new legislation combines with the regulations laid out in AB 68, AB 881, and SB 13 to create a robust and comprehensive framework for the designing, permitting, construction, and use of ADUs in California.

In-Depth Look At ADU Features And Restrictions For 2025

When it comes to size limits in ADU law for California , the guidance is generous but a little confusing. Let’s break it down for you:

• JADU: 500 sq ft max.
• ADU: Must permit 800 sq ft regardless of other requirements.
• 1-BR ADU: 850 sq ft max if in compliance with local rules.
• 2-3 BR ADU: 1000 sq ft max if in compliance.
• Absolute max: 1200 sq ft, subject to local rules.
• Attached ADU: Limited to 50% of the main home’s square footage.
• No limit: Converting accessory structures like barns or garages.

In addition to all this, there are new minimum height limits of 16 feet for detached ADUs, or 18 feet if the lot is located within a half-mile of a major transit stop. The limit is 25 feet for attached ADUs, based on zone height or that of the main house (whichever is lower).

Previously, a 800 sq ft ADU encroaching on the front setback could lead to application denial, but that restriction is now lifted. Cities can’t withhold demolition permits if an ADU permit is issued during construction.

ADU Design Specifics: JADU Bathrooms And Fire Sprinklers

In a junior ADU, also known as a JADU, homeowners are no longer required to include a bathroom in an attached JADU. This 2023 change to ADU laws in California applies as long as the bathroom in the primary residence is accessible to the JADU, making it easier to add this type of residence onto a property.

Senate Bill 9 has updated requirements relating to fire sprinklers. Under the previous legislation, homeowners were required to install fire sprinklers in their primary residence upon building an ADU. This mandatory requirement has now been removed as of 2023, making it simpler to build and sell an ADU property in Contra Costa.

New ADU Laws In Specific Areas Of California

Remember that the specifics of the new ADU regulations can vary by county or city. What is true in San Diego may not be true in Los Angeles, so it is important to do your research and seek expert advice to make informed decisions.

Understanding Owner-Occupancy And Rental Aspects Of The New ADU Laws In Ca

The changes to California ADU laws in 2025 make permanent the existing prohibition on local government’s ability to require owner-occupancy on a parcel containing an ADU. This increases flexibility for property owners who wish to construct an ADU for any purpose.

If you have an unpermitted ADU and wish to rent it out, you risk fines, insurance problems, and potential lawsuits from tenants. With the relaxing of ADU laws, you may be able to get your existing ADU approved , but you will need to ensure it complies with the regulations.

These issues have been common barriers for people seeking ADU permits, which is a contributing factor to the problem of unpermitted ADUs throughout the state. Local government has recognized the strong market for building ADUs, so the changes to ADU law in California have come into force  to help make the entire process easier.

Looking Ahead: Anticipating 2025 ADU Laws

With the 2025 California ADU laws removing deadlines on regulations that were due to expire in 2025, it looks likely that the current status is set to continue. The new legislation opens the market up substantially, so it’s important to educate yourself on what can and cannot be done.

In January 2025, we saw AB 2533, SB 1211, and SB 1077 come into effect, further altering the ADU landscape in California and helping to address the housing problems in the state.

Recent Modifications In Existing ADU Laws

We mentioned the 60-day rule earlier in this post. The changes to ADU law in California essentially make these more transparent. Permitting offices have been required to approve or deny ADU permits within 60 days since 2020, but many simply issued a denial as soon as the 60 day limit was reached. As of 2024, they must provide a detailed list of reasons for a denial, including descriptions of how to make improvements.

Another recent modification is SB 897, which eliminates the restriction on homeowners building an ADU if unpermitted work is discovered on the property. It also:

• Prevents cities from blocking a permitted ADU construction by denying a demolition permit.
• Removes the requirement for fire sprinklers in the primary dwelling when building an attached ADU.
• Enables a JADU to be built without its own bathroom, as long as the primary residence’s bathroom is accessible to the JADU.

With these changes to ADU laws in California , it is set to be easier and more versatile to construct and use accessory dwelling units . It is hoped that this will address the problem of increasing unpermitted ADUs and provide new opportunities for homeowners to generate income and young families to get a foot on the housing ladder in California.

This article was originally written by Renée White and appeared here.