Services › ADU Image 1 of 1 ADU $0.00 An Accessory Dwelling Unit (ADU) is a secondary housing unit located on the same property as a primary residence. ADUs can take various forms, such as a converted garage, basement apartment, or a separate structure in the backyard. They are designed to provide additional living space, often used for rental income, accommodating family members, or addressing housing shortages. Request for quote Added! An Accessory Dwelling Unit (ADU) is a secondary housing unit located on the same property as a primary residence. ADUs can take various forms, such as a converted garage, basement apartment, or a separate structure in the backyard. They are designed to provide additional living space, often used for rental income, accommodating family members, or addressing housing shortages.