What is an adu?

An accessory dwelling unit (ADU) is a small, self-contained residential unit located on the same lot as an existing single-family home. Accessory dwelling units include basic facilities needed for day-to-day living independent of the main home and include a living space, kitchen, sleeping, bathroom, and have a lockable entrance door.

Forms of an ADU


The traditional style accessory dwelling unit (ADU) that connects to an existing house. The units can have a separate or shared entrance and is typically constructed along the side or rear of the home.

Attic conversion

Makes use of the attic space in the home to become a dwelling unit.

Garage Conversion

The garage can either be converted to a full residence. Other options including adding a second story accessory dwelling unit above or beside the garage.

Basement Conversion

Coverts the basement into its own residence with a separate entrance. 

Backyard Cottage

Stand-alone home built on the same lot as the primary residence. Also known as a Detached Accessory Dwelling Unit (DADU)

Timeline to Design and build

The average timeline to design and build an ADU or DADU can range widely from a few months to over 2 years depending on the jurisdiction, type and customization. An internal renovation in an ADU friendly jurisdiction may be completed in weeks while a fully customized DADU could take over 2 years to design, permit and build.

Benefits of an ADU


More modest, affordable home choices in all our communities.


More options for people of all incomes to live near jobs, schools, transit, and parks. 


Freedom for homeowners to age in place, care for family, and earn income from a small rental. 


Build economic security and housing stability for middle and low-income families with workforce housing near jobs. 


Small, efficient homes in existing neighbourhoods help prevent sprawl, cut traffic and commutes, tame infrastructure needs, and fight climate change. 


Every community has a part to play, allowing homes that work for families across the state. 

ADU news