Building an ADU in California and Washington: A Breakdown of Construction Time and Laws

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Abodu Team

In recent years, backyard living has seemingly become an antidote for some communities dealing with rising housing prices on America’s West Coast. Many states, including California and Washington, are enacting laws to make it easier to create affordable housing and increased population density on preexisting land. These new regulations reflect the growing concern amongst lawmakers about creating sustainable density in their communities. Abodu has been working closely with municipalities to cut red tape and make smart density the new normal.

Building an ADU in California

Since 2017, California has reduced most fees that used to accompany building ADU homes. The state has now recognized that accessory dwelling units are a vital tool in solving the housing crisis. Under Proposition 13, adding an accessory dwelling unit to your property in California does not cause an increase in your property tax for your existing home; rather, it just increases your improvement value. In October 2019, California published AB-881 and 69, making it easier for homeowners and accessory dwelling unit builders to get approval to begin new building projects. This law made many local restrictions on ADU construction obsolete and sped up the ADU building process by requiring either a denial or approval to start ADU construction within 60 days of the request. As of 2021, California Health and Safety Code (HSC), Section 65583(c)(7) states that cities and counties throughout California instate a plan that incentivizes the installation of ADUs offered at affordable rent prices. These requirements are targeted at low-to-moderate income households. The California Department of Housing and Community Development (HCD) lists a variety of grants and financial incentives aimed at the costs for the planning, operation, and construction of ADUs. For more info about ADU guidelines in California, check out the HCD’s ADU handbook. Because of all these incentives and Abodu’s built to order process, Abodu can have your ADU in your backyard in as little as six months. Additionally, Abodu has pre-approved and expedited permitting plans with multiple cities in California. In San Jose and Los Angeles, Abodu uses pre-approved plans to install an accessory dwelling unit in as little as 30 days.

Building an ADU in Washington

According to, RCW 43.63A.215 and RCW 36.70A.400 require many Washington cities and counties to have intact policies encouraging the development of accessory apartments in single-family zones. While state laws allow local communities some flexibility, the above laws state that local codes must incorporate model ordinance recommendations prepared by the Washington State Department of Community. Additionally, some Washington cities like Seattle are looking into enacting laws that will streamline the permitting process by providing pre-approved ADU plans.

How Abodu Speeds Up ADU Construction in California and Washington

Abodu’s accelerated timelines work with local municipalities across California and Washington to speed up your ADU construction process. By allowing us to take care of the heavy lifting, we can take the frustration out of expanding your home and have it done in as little as six months. Learn more about how we make ADU construction simple by filling out our form today. Share on facebookShare on Twitter(

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