Accessory Dwelling Unit (ADU)
Also: ADU · granny flat · in-law unit · casita · backyard home
An accessory dwelling unit (ADU) is a second, independent home on a single-family or multifamily lot, with its own kitchen, bathroom, and entrance. In California it can be detached, attached, or converted from existing space, and can be rented separately from the main house.
Across the Sacramento region a single-family lot can typically hold one ADU plus one Junior ADU. ADUs are permitted ministerially (by-right) under state law, which is why they avoid the discretionary review a normal home addition can trigger. In practice a Sacramento homeowner can detach a new backyard unit, attach one to the main house, or convert an existing garage or interior room, and each path follows the same by-right permit channel. The most popular local route is a detached unit sized just under 750 square feet, because that keeps it fully exempt from impact fees while still renting as a true standalone home, separate from the main house and on its own lease.
Go deeper:What is an ADU? Full explainer · ADU services & build types
Related terms
Back to the ADU glossary.