Yolo County, CA Accessory Structures: ADU Rules (2026)

(1) Accessory dwelling units (ADU) in residential zones are a permitted use only subject to the requirements set forth separately below and in no case shall an ADU that meets the minimum requirements be subject to discretionary review. A ministerial permit for an ADU may be disapproved only if the Planning Director finds that the ADU would be detrimental to the public health and safety or would introduce unreasonable privacy impacts to the immediate neighbors. A building permit application for an ADU shall be approved or disapproved within 120 days of receipt. (2) The maximum height of an ADU within a required setback shall be 16 feet. (3) The following setback requirements for ADUs shall apply: (i) Setbacks for existing structures or conversion of structures. No setback shall be required for an existing living area or accessory structure or a structure constructed in the same location and to the same dimensions as an existing structure that is converted to an accessory dwelling unit or a portion of an accessory dwelling unit. (ii) New construction. Newly constructed ADUs that do not result from the conversion of an existing structure shall require a setback of four feet from the side and rear property lines. (iii) Building separation. Detached accessory structures subject to a Building Permit shall be separated from principal structures by a minimum of ten (10) feet and from other detached accessory structures subject to a Building Permit by a minimum distance specified by applicable building or fire codes. (4) The following parking standards shall be required of all accessory housing structures except as noted for an ADU: (i) One parking space shall be provided per accessory dwelling unit. Parking for an ADU may be provided as tandem parking on an existing driveway. Parking lost through the conversion of a garage, carport, or covered parking structure is not required to be replaced. Additional parking for an ADU is not required if the ADU is located: 1. within one-half mile walking distance of public transit; 2. within an architecturally and historically significant historic district; 3. within an existing primary residence or an existing accessory structure; when on-street parking permits are required but not offered to the occupant of the accessory dwelling unit; or 4. when there is a car share vehicle located within one block of the accessory dwelling unit.