Knowledge Base

An accessory dwelling unit (ADU) is a small, secondary living unit allowed in residential areas. An ADU is commonly known as a granny flat, and in-law suite, or a carriage house.

When the Unified Development Code (UDC) went into effect on January 1, 2023, accessory dwelling units became eligible accessory uses in all residentially zoned districts. The requirements listed below will be applied to ADUs in the City. These requirements and additional requirements for ADUs come from Section 60.300.020G: Accessory Uses and Structures of the UDC.

• There shall be no more than one accessory dwelling unit on a lot
• An accessory dwelling unit must not contain more than 1,000 square feet of gross floor area.
• Detached accessory dwelling units shall only be located in the rear or side yard.
• The architectural style of the accessory dwelling unit, including but not limited to massing, roof shape, and exterior appearance shall be compatible with that of the principal dwelling unit on the lot.

Learn more at Accessory Dwelling Units (ADUs) | City of Rochester