adus

ADUs, or accessory dwelling units, are secondary housing units situated on the same lot as a primary residence. They can be detached or attached to the main dwelling, or created through conversions of existing spaces such as garages, basements, or attics. An ADU generally provides independent living facilities, including a kitchen, bathroom, and sleeping area, with its own entrance.

Regulation varies widely by jurisdiction. Local zoning, building codes, and permitting processes determine whether an ADU is allowed, its size, parking, setbacks, and occupancy rules. Many cities have moved toward streamline approvals and fewer parking requirements to encourage construction, while some areas still impose restrictions or owner-occupancy conditions. Typical ADU sizes range from roughly 200 to 1,000 square feet, but local rules vary.

ADUs offer several potential benefits. They can increase housing supply and affordability, support multigenerational living or short-term rentals, and provide homeowners with rental income or funds for property maintenance. They can also help veteran, student, or aging populations remain in their communities. Challenges include regulatory barriers, high construction costs, limits on utility capacity, and concerns about parking, neighborhood character, or property values.

Policy interest in ADUs rose in the 2000s and 2010s as cities sought housing solutions. Several jurisdictions, including California and Oregon, implemented statewide or citywide reforms to simplify approvals and expand allowable ADU types. As a result, ADUs have become a common feature in planning discussions about denser, more affordable neighborhoods while requiring careful design and community engagement.