An ADU is defined as having a second small dwelling that sits on the same property as a regular single-family house—or is attached to it. Typically, these take on the form of an apartment over the garage, a tiny house on a foundation in the backyard, or a basement apartment. The rules vary by jurisdiction, but usually, these buildings are required to be less than 800 square feet or a percentage of the existing home's area. Sometimes, people design and build their ADU with the purpose of moving into it themselves, and then renting out their main home.
If you're thinking about taking the leap and building an ADU on your property, consider visiting some examples to make sure you're comfortable with downsizing. Many cities have ADU tours, such as Portland's annual Build Small, Live Large Tour in September. Take a look at some creative ways people have incorporated small living into their lives.