ADUs and Middle Housing

Interested in Building an ADU or Middle Housing? 

Are you considering building an Accessory Dwelling Unit (ADU) or Middle Housing (MH) on your property? These housing types offer flexible living options, support multigenerational households, and help increase housing choices within our community. Whether you're a homeowner, builder, or designer, this section will help you understand the basics and get started.

What Are ADUs and Middle Housing?

Accessory Dwelling Units (ADUs) are smaller, independent residences located on the same lot as a primary home. They can be attached (like a basement apartment or converted garage) or detached (like a backyard cottage). They are allowed to be a maximum size of 800 sq. ft. floor area, with an allowance for an additional 200 sq. ft. if the ADU is part of a conversion of existing primary dwelling space.

Middle Housing (MH) refers to housing types that fall between single-family homes and larger apartment complexes. These include duplexes, triplexes, quadplexes, cottage clusters, and townhomes. They are intended to blend into existing neighborhoods while providing more housing options. These can be owned individually, made into condominiums, or divided through a Middle Housing Land Division (MHLD) for fee-simple sale. 

Where Are They Permitted?

ADUs and Middle Housing are permitted in all residential zones in the city, with the exception that ADUs are not allowed in the R-W (Residential-Waterfront) zone. This flexibility makes it easier for property owners to consider building these types of housing across most neighborhoods in the city. Most residential zones allow one ADU per lot with a single-family dwelling. Restrictive covenants that may prohibit the constriction of middle housing or accessory dwelling units are no longer enforceable under state law. Note that certain environmental and design overlays may affect the buildability of your lot. Additionally, flag lot access lanes are not permitted to serve anything denser than a duplex (or two units per lot).

Learn More

For detailed information, including development standards, design requirements, and the permitting process, refer to the guides below:

• Accessory Dwelling Unit Guide
• Middle Housing Info Sheet
• Residential Infill Design Guide
• Middle Housing Land Divisions Guide
• Middle Housing and MHLD Recommended Timeline
• Adjustments/Variances for Housing Processes

Additional Questions?

Contact Planning Staff for help navigating your project. Additionally, contact the Engineering and Building Departments to understand what is required for your project early in your process.