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Accessory Dwelling Unit (ADU)
An accessory dwelling unit is a second, smaller home on the same lot as a main house, with its own kitchen, bathroom and entrance. It is also called a granny flat, in-law unit, backyard cottage or secondary suite.
An ADU can be detached, attached to the house, or built inside it, for example in a converted basement or garage. Owners use them to house family members or to rent out.
Local zoning controls whether ADUs are allowed, how large they can be and whether one of the units must be owner-occupied.
An ADU is measured separately from the main house and is not added to the main dwelling's living area. See ADU square footage.
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