Regardless of what they're called, an accessory dwelling unit, also known as an ADU, is an additional living quarters on single-family lots that is independent of the primary dwelling unit, according to the U.S. Department of Housing and Urban Development. The separate living spaces are equipped with kitchen and bathroom facilities, and can be either attached or detached from the main residence. ADUs have been steadily gaining popularity due to their flexibility. They’re originally designed to provide convenient and private housing to family members as they age. But these suites have evolved outside of this more traditional purpose and are now being used to provide housing for younger family members as they save for their place, or to help the homeowner generate passive rental income. ### Types of ADUs - **Attached** - An ADU that is connected to the main house or part of the primary residence but is designed to be an independent living space. - **Detached** - A detached in-law suite is often a smaller, standalone structure built on the same property as the primary residence. - **Interior ADU or a converted existing space** - This type of ADU is a separate unit located inside the main house. ### Key Considerations 1. Local building codes and zoning laws 2. Purpose 3. Utilities and infrastructure 4. Budget and financing