Accessory Dwelling Units (ADUs) are secondary housing units on the same grounds as a primary residence. These units, often referred to as granny flats, in-law units, or backyard cottages, provide unique opportunities for homeowners and investors. ADUs can be used for rental income, accommodating family members, or increasing property value. In California, the growing interest in ADUs reflects a response to the housing shortage and the need for more affordable housing solutions.