San Jose ADU Rules & Regulations

ADU Zoning, Location, Setback & Design Regulations for San Jose, CA

Learn about the most recent ADU requirements in San Jose, California, as you prepare to build the perfect accessory dwelling unit on your property.

Benefits of Accessory Dwelling Units

Property value increase
0 %
average monthly rental income
$ 0
Return on investment (ROI)
0 %
Build Your Ideal Accessory Dwelling Unit with Valley Boutique Builders

San Jose Adu Zoning Requirements

Before building, you need to ensure your property is in the correct area and zone. 

You can contact the San Jose Permits Office to determine whether or not your home is within the jurisdiction of the City of San Jose or within a residential zoning that starts with R-1, R-2, R-M, or PD. 

If your home isn’t in the zones listed above, you cannot build an ADU onto your property.

Furthermore, single-family homes are allowed one ADU and one JADU, or junior accessory dwelling unit, per lot, while multi-family properties can build two detached ADUs. Duplexes can build an attached ADU. 

Get the most out of your ADU in San Jose

Discover the Benefits of ADUs Versatility, Functionality, and Value.

ADU Size Requirements

Permitted sizes for ADU on single-family lots differ based on their square footage. 

If your lot is under 9,000 square feet, the detached ADU can be at most 1,000 square feet, while any attached ADUs can be 800 square feet or 50% of the main residence. While lots with 9,000 square feet or more, the detached ADU can be 1,200 square feet or less. Attached ADU may be 50% of the main residence or 800 square feet, but at most 1,200 square feet. 

If your lot has a JADU or a detached ADU that is at most 800 square feet, it is permitted, but you cannot add an attached ADU.

Height Requirements

Any single-story detached ADU cannot exceed a maximum height of 18 feet, while two-story ADUs have a limit of 24 feet. According to state law, if your property already has a JADU, the maximum for the ADU is 16 feet.

Any duplex or multi-family home can build a detached ADU, and the maximum height for the ADU is 16 feet. 

Maximum ADU Sizes & Heights in San Jose

Height and size also depend on the home type. If you are a single-family homeowner with an attached ADU, your ADU needs to comply with the height limitations of the main dwelling.

Requirements for Detached ADUs

For single-family homes wanting to build a detached ADU location, the ADU must be in the rear yard or 45 feet from the property line. They can be newly built or transformed from a detached garage or accessory building or added to an attached ADU.

Requirements for Attached ADUs

For homeowners building an attached ADU, the ADU has to share a wall or roof structure with the main residence and cannot be separated by more than 10 feet. If the attached ADU is located in the front yard, the front door cannot be on the same street-facing facade as the main residence. 

For JADUs, the new addition’s location must be within the home’s footprint.

Property & Location Requirements for San Jose ADUs

There are different property requirements depending if you are building an attached ADU or detached ADU.

ADU Setback Requirements in San Jose

Setback requirements vary depending on the home type and whether or not they are detached or attached. Attached ADUs cannot be added or built onto existing multi-family homes or duplexes, so there are no setback requirements for those.

Single Family Homes

Single-family homes with detached ADUs must be at least 45 feet from the front property lines and have side and rear setbacks that are at least 3 feet from or comply with the fire mitigation measures.

Multi-Family or Duplex

For multi-family or duplex homes, the detached ADU has to be situated in the rear yard or at least 45 feet from the front property line, side and rear setbacks of 4 feet, and cannot have a second story.

New or
Two-Story ADUs

Any new or two-story ADU with more than 40% yard coverage must be 4 feet from the rear and side property lines.

ADUs with Decks or Balconies

If your future ADU has a deck, second-story balcony, or any unenclosed entry landing like a walkway or porch, there must be at least a 15-foot rear or side setback.



We had no idea how much it cost to build ADUs when my mother in law came to stay with us. We all desperately needed our own space and speaking to the team put our minds at ease as it was actually affordable to have an ADU done. Plus the process was so unbelievably simple. The team listened to what we needed and everything was done on time and within budget. She loves her new space and now we are all happy with our privacy.

Thomas G.

We chose Valley Boutique Builders for our home remodeling project, and it was the best decision we made. Their knowledge, skill, and personal attentiveness were evident from the start. They guided us through the entire process, offering valuable insights when we wanted something that wouldn’t be to their standards and they delivered outstanding results. Our home’s new look is just wonderful and we couldn’t be happier.

Andrew and Megan D.

My new bathroom is absolutely luxurious! The attention to detail is evident throughout the entire bathroom. A special mention goes to the elegant tiles and the meticulous workmanship. Thanks again for an incredible job.

Emily S.

Every San Jose ADU is different

Find inspiration for yours by viewing recently completed projects.

The Valley Boutique Builder ADU Experience

Choose Valley Boutique Builders for your ADU project and benefit from our expertise in interior design and construction management.

Our proven design-build process ensures that your ADU is tailored to your goals, budget, and timeline. With personalized attention and exceptional service, we keep you informed and involved throughout the entire process.

Count on us to deliver a structurally sound and stunning ADU that exceeds your expectations, creating a remarkable living space.

ADU Permit Application

We guide you through a seamless permit application process.

Custom Accessory Dwelling Unit Design

We make your dream a reality, merging bespoke design with excellent ADU construction.

Build Your San Jose ADU on Budget

Working closely with your to meet your needs, on time and on budget.

More About Building ADUs in San Jose

An Alternative Dwelling Unit, or ADU, is a self-contained living unit that is secondary to the main house on a residential property. It is also commonly known as a granny flat, in-law suite, or backyard cottage. 

ADUs typically have their own kitchen, living area, bathroom, and separate entrance, providing complete living facilities for one or more persons. They’ve become increasingly popular solutions for more flexible housing to accommodate family and friends or serve as another form of income. 

ADUs are designed to provide additional living space and can be used for various purposes, such as housing family members, generating rental income, or serving as a home office or guest house. The key difference between an ADU and a traditional home addition is that ADUs are separate living units with their own entrance, kitchen, bathroom, and utilities.

Yes, obtaining a permit is necessary for building an ADU in the Bay Area. The city of San Jose requires that all ADUs meet the California Building Code and the San Jose Municipal Code. As experienced contractors, we have a thorough understanding of the local regulations and building codes. We can guide you through the permit application process, ensuring that all necessary documentation and requirements are met to obtain the required permits

The price of a permit for an ADU can vary depending on several factors, including the size and complexity of the project. Permit fees typically cover plan reviews, inspections, and other administrative costs. At Valley Boutique Builders, we work closely with our clients to provide accurate cost estimates, including permit fees, during the preconstruction phase. Our goal is to ensure transparency and help you make informed decisions about your ADU project.

The cost to build an ADU can vary based on several factors, such as the size, design, materials used, and site-specific considerations.

While each project is unique, building an ADU is generally a cost-effective way to add living space to your property compared to traditional home additions.

Our team of experts at Valley Boutique Builders will work closely with you to understand your goals and budget, providing you with a detailed cost estimate tailored to your specific project. We strive to deliver exceptional value by optimizing the design and construction process to ensure your ADU is built within your budget.

There are various types of ADUs including:

  • Home addition
  • Junior ADU
  • Detached and attached
  • Basement conversions
  • Above Garage ADU

Yes, the property tax on your house often increase; however, the home itself will not be reassessed. Your taxes (and property value) will increase based on the value of your addition.

Yes, you can have two detached ADUs if you own a duplex or multi-family home.

Embark on a transformative journey with us and together, we will bring your ADU vision to life and create a space that embodies your style and enhances your San Jose lifestyle.

Ready for the custom ADU of your dreams?

Fill out the form, or call us to set up a free in-home consultation.
Scroll to Top