Accessory Dwelling Units (ADUs)

ADUs on Lots with Single-Family Homes

An ADU on a lot with a Single-Family home is an attached or detached self-contained residential unit on the same property as the primary single-family residence that offers living, sleeping, eating, cooking and sanitation. Examples include a freestanding backyard cottage, a garage converted into a living unit, and a basement converted into an additional living unit.

Take the time to figure out which ADU fits your needs and budget. Three types of ADUs on lots with primary Single-Family homes are classified by the construction of new or the use of existing facilities. Please review the categories below:

• Junior ADU (JADU): Converting a space within the building of an existing or proposed Single-Family Residential Facility. No more than 500 square feet. Requires proof of ownership and owner-occupancy in the JADU or primary residence.
• Category One ADU: Either converting a space within a Single-Family Residential Facility or converting /rebuilding an existing accessory structure. The existing building cannot be expanded except to accommodate an ADU entrance or exit of up to 150 square feet.
• Category Two ADU: Construction of a new, detached or attached accessory structure. Includes an exterior addition to an existing or proposed Single-Family Residential Facility

Explore ADUs on Lots with Single-Family Homes

ADUs on Lots with Multi-Family Homes

ADUs on lots with Multi-Family homes are self-contained attached or detached residential units on the same property as the primary Multi-Family building. They provide complete independent facilities for living, sleeping, eating, cooking and sanitation. Please note that these ADUs are limited to housing only one family each. There are three types of ADUs for Multi-Family properties, depending on whether you are converting an existing structure or constructing a new one.

• Category One ADU: Conversion of existing non-habitable space within portions of an existing Multi-Family Residential Facility, such as storage rooms, boiler rooms, passageways, attics, basements or garages.
• Category Two ADU: Construction of new detached structure(s) or conversion or rebuild of existing detached structure(s) on lots with an existing Multi-Family Residential Facility. Conversion or rebuild of existing detached accessory structure(s) involves no expansion of the existing building envelope(s).
• Category Three ADU: Construction of a new or conversion of an existing accessory structure attached to a primary Multifamily Residential Facility to create only one ADU on the lot. This type of ADU precludes the creation of any other ADU types on the lot.

Explore ADUs on Multi-Family Lots

Pre-Approved Plans

Oakland now offers "off-the-shelf" pre-approved ADU building plans for properties with Single-Family or Multi-Family homes. You can view studio, one-bedroom and two-bedroom plans. These permit-ready plans are complete construction drawings that conform to the latest codes. Benefits of these pre-approved plans include:

• Faster approval
• Reduced permits fee
• Possible build cost-savings

ADUs have great benefits for the homeowner, renter and community such as:

• Generating income for homeowners who rent out the ADU
• Housing family or friends at risk of displacement
• Reducing the environmental footprint through small-scale living
• Creating extra space that can serve different functions
• Alleviating the housing crisis without changing the character of the neighborhood
• Removing barriers for people of different backgrounds to be a part of the neighborhood

Deciding to create an ADU is an investment and requires planning. Reflect on how you will use and pay for the ADU and if it will affect your property. After you decide which ADU you want to build, ensure it can be built where you want.

Is it Allowed on Your Land?

Your first step is to confirm that an ADU is allowed on your property. ADUs can be created on most lots that allow Single- and Multi-Family homes, except in special circumstances such as certain commercial or industrial areas or high-fire hazard areas with limited accessibility. Different requirements will apply depending on your zoning, the size of the ADU you want, and requirements such as whether you need to provide parking.

Please consult our zoning map to help you determine project feasibility.

Confirm Your Zone

What are the Costs?

The cost of building an ADU varies depending on the type you choose. Factors such as size, the condition of the existing space, and the quality of finishes all influence the overall expense. Additionally, you'll need to account for design, permits and fees, building materials, labor, and ongoing maintenance costs.

For example, a prefabricated ADU may cost $70,000 while a conversion of an existing accessory structure may cost as high as $460,000. Review estimates in our total development costs breakdown table.

View Our ADU Guide(PDF, 463KB)

Financing options, such as a home equity line of credit or renovation loans, are available to most homeowners. Regardless of how you finance, consider what debt you are comfortable incurring and how soon you'll see a return on investment.

Before you start building your ADU, you must create and get your ADU design approved. You can design your own ADU, or you can choose another way to design your ADU.

Although not required, a designer, licensed architect, or engineer is recommended to design the ADU and a licensed contractor to build it. Some companies provide both services. It is helpful when professionals have worked in Oakland and know the local permitting process. Contact references and look at the candidate's previous work before making your selection.

Use pre-approved designs: We now offer "off-the-shelf" pre-approved designs for use with properties that have Single-Family or Multi-Family homes. These permit-ready plans are complete construction drawings that conform to the latest codes. Using these pre-approved designs means the building permit process is quicker if your lot can house the ADU.

Upgrade pre-approved designs: You can also use pre-approved designs as a starting point for your project. Take a plan for a studio(PDF, 2MB), one bedroom(PDF, 2MB) or two bedroom(PDF, 2MB) and customize it for your needs and lot.

The state of California encourages people to build ADUs on their properties to benefit homeowners, potential renters and the community. This means that ADUs tend to have a quicker approval process than other types of homeowner projects. For all types of ADUs, the City has a two-step online application process.

Planning/Zoning Permit Approval: Focused on issues in the zoning code, such as the ADU location on property, size, height, etc. A zoning permit approval is required before applying for a building permit approval.

Building Permit Approval: Focused on making sure the ADU is designed to meet all building code requirements and determining if you need a private sewer lateral. A building permit is required before beginning any construction or demolition activities.

To find out how to apply for an ADU, please select the type of ADU you are interested in learning more about.

ADUs have state and local code requirements such as general building and CALGreen building standards codes. For example, you need a tree removal permit before removing any trees from the lot. You may also be in charge of managing stormwater drainage during construction.

Take a moment to familiarize yourself with these important codes that can affect your build. If you hire a contractor, they can help you navigate the City's codes. You can also contact our team at any time during your project journey.

If you have any questions about permits, codes, costs or anything else during any step of your ADU journey, we are here to help. You can call us at (510) 238-3891. You can also fill out our form to get your questions answered. We also have a list of common questions with answers.

View our ADU FAQ