An ADU (accessory dwelling unit) is a small detached unit that is built to accompany another structure, typically a single-family home. Recently, municipal governments have loosened the restrictions on these units following a California state mandate aimed at boosting dense and affordable housing infill.  An ADU is a valuable asset and can provide homeowners with passive income as well as the opportunity to house a multigenerational family. Its compact and refined design makes it efficient and economical while maintaining a desirable aesthetic that is suitable for a range of inhabitants.