ADU

The definitive guide to East Bay accessory dwelling units 

A high-level primer on ADUs in the East Bay

Accessory dwelling units (ADUs) -- aka granny flats, in-law suites and secondary units -- are immensely attractive to East Bay homeowners and homebuyers, as they allow residents to comfortably host guests or family members, develop studios and generate income as short- or long-term rentals.

Defined as a dwelling that provides complete independent living, eating, cooking and bathroom facilities located on the same lot as an existing single-family home, ADUs come in two types: detached, such as a casita in the backyard; and attached, such as a converted attic or backroom connected to the main house. These units are used for everything from art studios to rentals to guest houses.

ADUs can be appealing to communities as they facilitate the development of diverse housing types, add to rental stock, increase affordability by lowering rental housing prices (in some cases), and provide more opportunities for families to age in place. However, ADUs also come with a fair share of controversy as communities grapple with ensuring they improve (or at least do not detract from) residents’ quality of life. 

ADUs can affect neighborhood density and, if cities allow owners to use them as short-term rentals (such as through sites such as Airbnb or VRBO), they can increase traffic and busy-ness in settled neighborhoods. Many cities strive to make sure that their ADU policy maintains neighborhood character and minimizes the impact of short-term rentals so that parking and high-turnover visitors don’t disrupt neighborhood security or safety.

ADU1But this primer does not address these issues; rather, we present a fact-based overview of ADUs to help East Bay homeowners and buyers better understand and assess city policies so they can make better decisions. This is a high-level ADU outline designed to orient readers to the subject. Readers should reach out to an agent, the city or an architect or designer for more nuanced, precise, up-to-date information.

Because housing is arguably one of the most vital elements to a city’s unique texture, cities develop their own ADU policies. Below we’ve outlined the ADU regulations for five of our largest Inner East Bay cities: Oakland, Berkeley, San Leandro, Alameda and Richmond.

Each city has slightly different policies, but they all share three basic policies: they allow just one ADU per main home, ADUs must appear subordinate to the primary home and ADUs cannot be sold separately from the main home. 

Each area has specific rules for short- and long-term renting, owner occupation and setbacks -- the amount of space from the main house and also from property lines. We leave some of the more nuanced specifics of ADU policy out of this higher-level overview.

 

Oakland

In Oakland, property owners are not required to live in either the ADU or the main home. Richmond is the only other East Bay city with this same component of ADU policy.

Oakland’s requirements explicitly state that the ADU needs to be smaller than the main home but be visually compatible.

Oakland ADU policy summary*

 Occupancy requirements

The property owner is not required to live in either the primary home or ADU.
Renting + selling The ADU may be rented, but may not be sold separately from the primary dwelling. The ADU may only be rented out for 30 days or longer. 

Architectural compatibility

ADU must appear clearly subordinate to the primary house in size and location; exterior materials must match or be visually compatible. 

Max floor area + height Floor area may not exceed 800 square feet or 75 percent of the floor area of the existing home, whichever is less. For detached secondary units, maximum wall height is 10 feet and roof height is 14 feet.
Parking requirements Required parking spaces may be provided as tandem parking on an existing driveway or in required setbacks.


*This information was generated from the Oakland city website. City policies may be updated on a regular basis. We recommend that you check with the city to confirm current requirements. 

 

Berkeley

Unlike Oakland, Berkeley does not allow landlords to live away from their ADU properties. In fact, they must sign an agreement that they will live in either one home or the other and, additionally, must record a deed restriction with Alameda County agreeing never to sell the ADU separately.

In order to rent an ADU, Berkeley homeowners must register it through the Berkeley Rent Stabilization Board. However, Berkeley is more flexible than Oakland when it comes ADU appearance; it provides no aesthetic architectural specs, although floor area can’t exceed 850 square feet and detached ADUs cannot be more than 14-feet high.

As far as setbacks and safety, Berkeley ADUs must have be setback at least four feet from the sides and rear of the property. Off-street parking specifically is not required, but if the ADU is created out of a working parking space (i.e., converted garage), then homeowners must create a separate parking space.

Berkeley ADU policy summary*

Occupancy requirements

Property owners are required to sign an agreement stating that they will live in either the primary dwelling or the ADU.
Renting + selling An ADU cannot be sold separately from the primary dwelling unit. All rentals must be registered through the Berkeley Rent Stabilization Board. ADUs cannot be rented as short-term rentals if they were approved after April 1, 2017.
Architectural compatibility Not explicitly stated.
Max floor area + height The gross floor area of an ADU cannot exceed 850 square feet. Newly constructed ADUs (or conversions of other spaces into ADUs) cannot be more that 14-feet high. 
Parking requirements An off-street parking space is not required for a newly created ADU. If an ADU is created from a garage or an area that provides off-street parking for the primary dwelling unit, replacement parking for the primary dwelling unit is required.


*This information was generated from the Berkely city website. City policies may be updated on a regular basis. We recommend that you check with the city to confirm current requirements.

[ADUs give homeowners significant flexibility and are a significant buyer perk. Reach out to us if you’re thinking of adding an ADU or are hunting for a home with one to get expert real estate perspective on the move.]

 

San Leandro

The most picky about ADU aesthetics of all East Bay cities, San Leandro requires all ADU applications to include a plot plan, floor plans with detailed elevations and cross sections, and a deed restriction stating that homeowners will never separately sell the unit.

San Leandro provides specifics about floorplan specs, building materials and entryways. The city also requires one parking space for each ADU bedroom.

San Leandro ADU policy summary*

Occupancy requirements

Owners must occupy either the main dwelling or the ADU.
Renting + selling Homeowners cannot sell ADUs separately from the primary dwelling unit, and renting shorter than thirty days is prohibited.
Architectural compatibility ADUs must appear subordinate to the existing dwelling and the styles must fit. Single-story and two-story ADUs are allowed. Exterior stairways to second-story ADUs should not be visible from the street.
Max floor area + height New-construction ADUs built above the first-floor roofline are prohibited except when existing habitable space above the first-floor roofline is converted.
Parking requirements One parking space is required for a one-bedroom ADU, with one additional space being required for every additional bedroom.


*This information was generated from San Leandro's building code policy. City policies may be updated on a regular basis. We recommend that you check with the city to confirm current requirements.

 

Alameda

In Alameda, ADU owners must be the current owner-occupant of the property, and, prior to beginning the building process, must sign a deed restriction prohibiting short-term rentals and the sale of the ADU separately from the primary residence.

Architecturally, ADUs must incorporate the same materials, colors, and style of the primary dwelling but be subordinate to it. Policy restricts floor areas to a max of 640 square feet or 50 percent the size of the primary dwelling, whichever is less. Each ADU must have a dedicated parking space for each bedroom.

Alameda ADU policy summary*

Occupancy requirements The applicant for an ADU must be the current owner-occupant of the property.
Renting + selling Short-term rental (less than 30 days) of the ADU is prohibited. The ADU may not be sold separately from primary residence.
Architectural compatibility ADUs must have similar materials and design as main house. Design review is not required for an accessory dwelling unit, but applications for a garage conversion do require a site development review.
Max floor area + height Max floor area should be 640 square feet or 50 percent the size of the primary dwelling, whichever is less. Height limit follows the same zoning requirements as primary dwelling.
Parking requirements One parking space is required per bedroom in the ADU.


*This information was generated from the Alameda city website. City policies may be updated on a regular basis. We recommend that you check with the city to confirm current requirements.

 

Richmond

Like San Leandro, the city of Richmond requires prospective ADU builders to submit an application package that includes plot plans, floor plans, elevations, cross sections, and color photographs of the site and adjacent properties. The city also requires deed restrictions indicating that homeowners will not sell the ADU separately from the primary dwelling.

The ADU guidelines, like Oakland, do not, however, require homeowners to live in either dwelling.

The city, however, has a privacy clause in its policy that stipulates that owners will take steps to lesson the privacy impacts of ADU windows and doors on neighbors. These can include obscured glazing, window placements above eye level, and orienting windows and doors toward the existing on-site primary residence.

Richmond ADU policy summary*

Occupancy requirements Owner not required to live in the primary home or the ADU.
Renting + selling Unit is not intended for sale separate from the primary residence and may be rented.
Architectural compatibility

The ADU must be clearly subordinate to the main dwelling, but policy specifies no design restrictions concerning shape, materials and style.

Max floor area + height No newly constructed ADU may have more than two bedrooms. Policy restricts ADU size to at least 150 square feet, and the ADU square footage cannot exceed 50 percent of the existing home, with a max of 1,200 square feet allowable.
Parking requirements The city requires one parking spot for each ADU bedroom. However, a parking spot is not required if the property is located within a half-mile of public transportation.


*This information was generated from the Richmond city website. City policies may be updated on a regular basis. We recommend that you check with the city to confirm current requirements.