A guide to Oakland ADU building regulations in California
Learn about local zoning guidelines, financing options, and getting started with building a custom ADU in Oakland, California.
Introduction to ADUs
A quick overview of what a backyard home offers for you, your family, and your property.
An ADU, or Accessory Dwelling Unit, is a secondary living space on your property that provides complete independence with its own living, sleeping, eating, cooking, and sanitation facilities. ADUs are also known as guest houses, in law suites, in law units, backyard cottages, and granny flats, and are built on the same lot as the primary residence or primary home. They can be attached ADUs that are connected your main house, or created as conversion ADUs by repurposing existing space, such as a garage conversion, often from existing single family homes. Alternatively, they can be built as new detached units.
There are many benefits to building an ADU, both practically and financially. It’s often more affordable than traditional homes since it leverages existing property and infrastructure, avoiding costly new developments. An ADU can provide as much living space as a modern apartment, making efficient use of your property. ADUs can provide extra income through rental opportunities, support affordable housing, and help stabilize neighborhoods by increasing housing options. They can generate rental income to offset mortgage payments, offer a private space for family members like aging parents, diversifies housing options, and increase your property’s market value. Plus, it’s eco-friendly, reducing the need for new construction and supporting sustainable living, especially in areas that are in a housing crisis.
ADUs are secondary to the primary dwelling unit and are located on the same property or same lot as the main home, providing independent living while remaining connected to the primary residence.
Key Benefits of a Backyard Home
Increases Property Value | A well-built and thoughtfully designed ADU can boost the market value of your property, often 25%- 35% higher in urban areas. |
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Provides Housing Housing Options for Family Members | Creates additional space and nearby independent living for your family, regardless of their age or needs. |
Expands Current Living Space | Adapts to needs like home office, guest house, or studio, and can include other spaces such as kitchens, bathrooms, or living areas. |
Generates Rental Income | Provides passive income, offsetting costs or funding expenses. |
Overview of ADU Construction Methods
There are a few of different ways that your ADU can be constructed
When building an Accessory Dwelling Unit (ADU), you’ll need to decide on the construction method. Common options include traditional, prefabricated (prefab), modular, and panelized construction, each with its own pros and cons. There are also several types of ADUs to consider: detached ADUs (standalone buildings separate from the main residence), attached ADUs (units built by adding onto or transforming existing structures like walls, basements, or garages), and conversion ADUs (created by converting existing spaces within a home or accessory buildings such as garages or sheds). Junior ADUs (JADUs) are smaller units, often up to 500 square feet, typically attached or converted from existing space within a single-family home, sharing some facilities and subject to owner-occupancy requirements. ADUs can also be added to a multi family building, not just single family homes.
- Traditional Construction involves building from scratch on-site, offering high customization but often taking longer and costing more.
- Prefabricated Construction means the ADU is built in a factory and delivered, providing speed and cost savings but with limited design flexibility.
- Modular Construction builds sections in a factory for on-site assembly, balancing speed and customization.
- Panelized Construction uses pre-built panels assembled on-site, offering a middle ground in cost and time.
When converting existing structures, buildings such as garages or sheds can be repurposed into ADUs, maximizing the use of your property. At Type Five, our approach combines the best of both worlds, offering you design flexibility with the cost savings and convenience of prefab. Here are some of the notable features:
- Customizable: Every Type Five ADU is customizable online. You can select the size, color, layout, amenities, bedrooms, finishings, and more without paying thousands of dollars in design fees.
- Turn-Key Experience: Thanks to our streamlined process, you can ditch the chaos and stress of managing the complexities of building your backyard home. We’ll draw up your plans to meet building codes, get them approved by the city, and manage construction so you don’t have to. Our platform allows us to be your project's architect and general contractor, saving you enormous time and money while giving you the peace of mind that you're getting an amazing service and product.
- Efficient Construction Timelines: A traditionally built ADU can take dozens of subcontractors and operate under a more bespoke process to get your ADU built. We've streamlined the number of contractors involved, and run a repeatable, consistent process for every home we build. You can expect clear timelines, little to no back and forth, and weeks instead of months of construction on your property.
- Transparent Pricing: We guarantee your price right in our design process before you even submit a deposit. You can say goodbye to financial surprises & unexpected “change orders” because every project comes with a guaranteed maximum price before the building starts. This means you can accurately budget for the other things in your life… like your retirement or that vacation you’ve been thinking about!
What’s the bottom line? If you want a backyard home but don’t want to deal with the hassle and expense of traditional construction, then prefabricated/modular construction is the way to go. And if you want the convenience of prefab with the flexibility of custom design, then we’ve got your back.
The Process
As a property owner, how an ADU gets built will vary based on who you choose as your partner, but here are the general phases. The ADU development process involves several phases, from initial planning to completion, and each ADU project is unique. Understanding the development process helps ensure your ADU development meets your goals and complies with local regulations.
- A site feasibility study will help determine what can be built and where.
- Exploration and refinement of the interior layout
- Selection of finishes and materials
- Finalization of design plans
- Preliminary budgets and timelines assembled for review
- Preparation of permit documentation
- Submittal to local building department
- Addressing any inspection comments
- Receiving permit approval
- Pre-construction planning
- Site preparation and foundation work
- Framing and structural assembly
- Plumbing, electrical, and HVAC installation
- Interior and exterior finishing
- Inspections
- Moving in and settling phase
- 30-day follow-up inspection
- Seasonal maintenance check-ins
- Warranty service as needed
- Future upgrade opportunities
Skip the hassle with Type Five
Our turnkey approach makes it a breeze to avoid the complex process of designing, permitting, and building your backyard home. With us, you'll reduce costs, avoid delays, and get your project done faster.
Oakland's ADU Regulations
Frequently asked questions about what you can build in Oakland, based on state and local regulations.
Feasibility
Can I build an ADU on my property in Oakland?
Yes, Accessory Dwelling Units (ADUs) in Oakland are allowed in all single-family residential, multi-family residential or mixed use zoning districts. On a single-family lot, a proposed or existing single-family home is required.
How many ADUs can I have in Oakland?
Under state law, a single-family home in Oakland may construct at least one Accessory Dwelling Unit (ADU). Owner-occupied single-family properties may also construct one ADU and one Junior ADU on the same property. Multi-family properties with four or more existing residential units may construct one ADU. However, the exact number of ADUs allowed on a property may vary depending on the specific regulations in place in your area. You should consult with the city of Oakland and your local zoning board to determine the specific number of ADUs allowed on your property.
Design
Is there a minimum lot size for an Oakland ADU?
There is no minimum lot size requirement. California state law also mentions that lot coverage requirements can’t preclude the creation of a statewide exemption ADU. A statewide exemption ADU is 800 square feet, with a height limitation of 16 feet and and 4 feet rear and side yard setbacks for lots with a single family home.
Is there a minimum and maximum size for an Oakland ADU?
In Oakland, the size of an Accessory Dwelling Unit (ADU) is determined by its category. Category 1 ADUs are have a maximum allowable square footage of either 50% of the existing primary unit or 800 square feet, whichever is greater. Category 2 ADUs have different size limitations depending on whether they are attached or detached ADUS. Attached Category 2 ADUs have a maximum size limit of 50% of the floor area of the primary house, or 850 square feet for one-bedroom units and 1,000 square feet for units with more than one bedroom, whichever is greater. Category 2 Detached ADUs are limited to a floor area of 1,200 square feet. Type Five's system can adapt to fit within these requirements, but most importantly to the available are you have to build.
Can you build a 2 story Oakland ADU?
It is possible to construct a two-story ADU, but it may be subject to certain limitations. For single family properties, the maximum height is determined by its category and its location on the property. Category 1 ADUs do not have any height restrictions, while Category 2 ADUs must be subordinate in height to the primary dwelling and must comply with the height limits of the underlying zoning district.
Additionally, any attached or detached ADUs located outside required setbacks must be limited to the height of the primary dwelling, except in certain specific zoning districts. It is recommended that you consult with the city of Oakland and your local zoning board to determine the specific height requirements for your proposed ADU. Multi-family properties usually have higher maximum height limits.
Type Five offers a two-story model that fits Oakland ADU requirements.
How many bedrooms can an ADU have in Oakland?
There is no limit to the number of bedrooms an ADU can have in the city of Oakland according to California state law. The California HCD ADU handbook states that a limit on the number of bedrooms could be construed as a discriminatory practice towards protected classes, such as familial status, and would be considered a constraint on the development of ADUs.
How close to the property line can I build an Oakland ADU?
The setbacks for building an ADU will depend on the type and location of the ADU. Under state law, newly constructed detached ADUs can be as close as 4 feet from the rear and side property lines. Attached ADUs and conversions from existing space that are expanded must comply with the setbacks of the underlying zone.
Permitting
Do I need a permit for an Oakland ADU?
Yes, building permits are required to construct ADU. The permit process will vary depending on the type of ADU you are constructing and the regulations in place in your specific location. At Type Five, we handle the entire permit process for you.
How long does it take to get a permit for an Oakland ADU?
The maximum amount of time the city of Oakland has to review your permit application is within 60 days of submission. It is possible to get your permit approved within 30-90 days of submission so long as your designs were drawn with the local building codes in mind.
Utilities
Does an ADU need its own electrical panel, water meter, or gas meter in Oakland?
In Oakland, the requirements for utilities in an Accessory Dwelling Unit (ADU) are determined by the category of the ADU. Category 1 ADUs do not require new or separate utility connection. Category 2 ADUs may require new or separate connection, but the connection fee or capacity charge must be proportionate to the burden of the ADU on the water or sewer system.
Are fire sprinklers required in an Oakland ADU?
In most cases, fire sprinklers are not required in an Accessory Dwelling Unit (ADU) in Oakland. An ADU is only required to provide them if sprinklers are required for the primary dwelling unit. However, the ADU must still meet other fire safety requirements, such as minimum fire flow and water pressure on the adjoining streets.
Is solar required on an Oakland ADU?
You may be required to install solar panels on your ADU if your ADU is a newly constructed, non-manufactured, detached ADU. There are exceptions to the state energy code based on floor area and climate zone. In Oakland (Climate Zone 3), you can qualify for an exemption if the size of the ADU is no more than 1,000 square feet.
Financials
How much can I rent an ADU for in Oakland?
You should be able to rent an Oakland ADU for $1,975 which is the average monthly rent for a one bedroom apartment so long as the rental term is longer than 30 days. There is no owner-occupancy requirement for ADUs built before December 31st, 2024.
Can an ADU be used as an Airbnb or short-term rental in Oakland?
You cannot use an ADU as an Airbnb in Oakland unless you are renting it out for a period longer than 30 days. California law states that ADUs created under subdivision (e) of Gov. Code, § 65852.2 cannot be rented for a period less than 30 days. This means you cannot use your ADU as a short-term rental in Oakland.
Can your HOA prevent your ADU build in Oakland?
Your local homeowners association (HOA) cannot prohibit the construction of an ADU or JADU in Oakland. Assembly Bill 670 (2019) and AB 3182 (2020) amended Section 4751, 4740, and 4741 of the Civil Code to preclude common interest developments from prohibiting or unreasonably restricting the construction or use, including the renting or leasing of, an ADU on a lot zoned for single-family residential use.
Covenants, conditions and restrictions (CC&Rs) that either effectively prohibit or unreasonably restrict the construction or use of an ADU or JADU on such lots are void and unenforceable or may be liable for actual damages and payment of a civil penalty.
How does an ADU affect property taxes in Oakland?
The city of Oakland will assess the value of your newly added ADU, typically by using the cost-bases method of appraisal, and multiply it by the property tax rate of 1%. So if your Oakland ADU costs $217,053 to build, you can expect your annual property taxes to increase by $2,170.53 per year. Adding an ADU to your property will not trigger a reassessment of the value of your primary house.
How much value does an ADU add in Oakland?
Adding an ADU to your property in Oakland typically adds value to your property, however, the exact amount depends on the appraisal method that your appraiser chooses to use. If an appraiser uses the cost-basis method & the cost of your ADU is $217,053, then you can expect your home value to appreciate by $217,053.
Another method that an appraiser can use is the sales comparison approach, where the value of the ADU addition is determined by recently sold properties in Oakland that included ADUs. However, this approach depends on the number of recently sold properties and there sometimes isn’t enough information to use this approach with ADUs. A back-of-the-envelope way to estimate the value yourself would be to multiply the existing price per square foot of your property by the square footage added by the ADU and compare it to the cost of your ADU. The appreciation is likely in between those two numbers.
How much does it cost to build an Oakland ADU?
The average cost involved in building an Oakland ADU is $217,053. Keep in mind there are a ton of factors to consider when estimating the cost of a project, many of which are unique to your property and sometimes require special surveys to identify. Examples of these factors include whether or not your property is flat or sloped and whether or not you need to upgrade your utilities.
It’s also important to note that converting an existing structure or converting your garage into an ADU isn’t necessarily cheaper than building a brand new detached ADU. You can get an in-depth overview about what goes into an ADU project in your city by starting to customize your ADU using Type Five's design tool.
Online Resources
Learn more about building in Oakland, California
City of Oakland ADU Permitting Site
Oakland ADU Loan Program
Oakland Planning Code, ADU Section 17.103.080
