By the start of next year, Californians looking to add accessory dwelling units to their backyards will be able to shop around for preapproved plans on their local city website as part of a statewide push to make the process easier and encourage more affordable housing to be built. 

A new law passed last year — Assembly Bill 1332 — requires local municipalities to establish websites with visual images and contact information of preapproved (or “pre-reviewed” in the words of some local city officials) designs of small backyard dwelling units available to property owners in any given city. As part of the new law, cities also must then approve or deny applications for any of those designs within 30 days. 

With less than three months before the new regulations go into effect, we decided to see where Midpeninsula cities are in the process. 

Menlo Park

Deanna Chow, Community Development Director for Menlo Park, said her city of 31,000 residents is currently evaluating ADU designs and plans to have a pre-approval program up and running by the first of the year.

The city approved permits for 63 ADU units last year — a 12.5% increase over 2022, Chow said.

While she views them as a helpful tool to ease the region’s housing shortage, ADUs are not necessarily a wide-ranging panacea for affordability challenges in famously expensive Midpeninsula cities.

“ADUs are a valuable source of housing and provide an additional option to meet the housing needs of a community,” Chow said. “While ADUs can be more affordable than other housing types, most are not deed restricted to lower-income households to address the affordable housing crisis.”

Redwood City

Further north, about 30 of the 73 approved permits for ADUs in Redwood City last year were built and approved for occupancy, according to James Dotson, Assistant Planner in the city Community Development Department’s planning division.

One of the region’s largest cities with 81,000 residents, Redwood City joins San Jose among local cities well ahead of the curve when it comes to ADUs. Through a partnership with the Housing Endowment and Regional Trust of San Mateo County for several years, the city has been offering what Dotson calls “pre-reviewed” ADU designs to interested residents.

Additional design options could be added by January, including studio, one-bedroom and two-bedroom units.

Dotson said the term “preapproved” can be a bit misleading, since city officials still review ADU applications and reserve the right to potentially deny them. Even the expedited schedule that takes effect Jan. 1 allows 30 days for official review, during which planning officials will assess plans to make sure they comply with local standards and city building codes.

Redwood City is one of several cities in the county included in an upcoming web portal collaboration called the ADU Resource Center of San Mateo County, Dotson said. Designers will be able to submit their ADU designs for review on the site, he said.

Dotson said the city’s existing online ADU resource will be linked to the county site.

“ADU legislation is just one tool for addressing the statewide housing crisis, and while we do not expect it to solve the problem overnight, we are hoping the pre-reviewed process will save our residents time and money in the long run to assist in creating new places to call home in Redwood City,” Dotson said.

Palo Alto

To help create a larger inventory of less-expensive housing in Palo Alto, the city’s Planning and Development Department is currently working on a process that will allow developers to submit ADU designs through its online permitting system. They will then make these designs available to the city’s 65,000 residents.

The department also plans to have a web page dedicated to preapproved ADU designs before Jan. 1, with visual images and contact information for developers, according to a department spokesperson.

Los Altos

Residents of nearby Los Altos also should have an ADU website to check out later this year, before the Jan. 1 deadline. Monica Gallardo-Melkesian, the city’s housing manager, said it will also likely link to state-sponsored sites with even more preapproved options.

She said cities in Santa Clara County also are collaborating with one another to facilitate the ease of getting residents’ ADU plans approved. Los Altos, a city of nearly 30,000 residents, approved 110 such plans in 2023.

“People are eager to see what their ADU options could be,” Gallardo-Melkesian said. “There’s a lot of interest.”

Bay Area and beyond 

Some cities are starting to pool resources or work with third-party organizations that can provide online tools for a regional ADU database that includes information for local cities.  

Inspired ADUs, an Oakland-based company that started more than two decades ago as a general architectural firm, but now specializes in designing accessory dwelling units, is among those working with municipalities throughout the Bay Area to make more preapproved plans available. It has designed and helped facilitate the construction of more than 200 ADUs statewide.

The company currently has modular designs that have been preapproved by the state’s Department of Housing and Community Development. Under the new law, these plans can be admitted into the local preapproval program. 

California has dramatically loosened its restrictions on ADUs since Inspired ADUs entered the market in 2010, said company principal Carrie Shores Diller. 

“The (ADU building) codes were very restrictive back then,” Shores Diller said, adding that only about one of every 30 applications would get approved 14 years ago.

Recognizing the growing need for greater housing flexibility, state officials began loosening the ADU guidelines in 2018, she said. Last year, 1 in 5 of all new housing units in the state was an ADU, double the number from 2020.

Though many ADUs are still “stick built” (constructed on site from the ground up), a growing percentage of them are fully or partially modular, Shores Diller said. Some are now assembled with sections built off site and literally carried or wheeled onto properties’ back or front yards.

No heavy machinery like cranes required.

“Our goal is to make ADUs more accessible to the public,” Shores Diller said. “And cities are working very hard today to do the same, to get better at this.”