What's an ADU?
An ADU is an accessory dwelling unit. These rentable, self-contained shelters provide, at a minimum, all the basic requirements for living: a bedroom area, kitchen area, and a bathroom. Many ADUs have additional rooms or areas. Some have a private entrance, while others are accessed through a common interior area.
Even though government zoning authorities use the official term ADU, individuals commonly give these residences other names, like private apartments, guest cottages, in-law suites, etc. As a rule, they generally fall into three broad categories:
Interior ADUs - Created by converting existing space inside a primary dwelling (usually in the basement or an attic).
Detached ADUs - A separate structure built on the same lot as the primary dwelling (like a cottage or detached garage).
Attached ADUs - Independent living space built as an extension of the primary home (laterally or vertically).
ADUs can play an essential role in solving older individuals' housing challenges, potentially providing options for aging in place and/or staying close to family members, while retaining privacy and independence.
(Excerpt from The SRES Professional)