An ADU is a separate, smaller living unit with its own kitchen and bathroom facilities and separate entrance that is included within a larger resident (type 1), attached to a residence (type 2) or located in an accessory (“detached”) structure on the same lot as a main residence (type 3). For a variety of reasons, primarily cost and feasibility, the type 1 ADUs are by far the most common.
In a 2019 study, MAPC found that: