Drought is Here - A mandatory 20% reduction in water use is currently in effect for City of Sonoma Water Customers.

What are the size and height requirements for Accessory Dwelling Units?

  • Attached accessory dwelling unit. The minimum floor area is 150 s.f.  The minimum dimension of any habitable room, except kitchens, is 7 feet in any horizontal direction (CA Residential Code R304.2).  The minimum ceiling height shall comply with the CA Residential Code. The maximum size is 30 percent of the existing living area of the main dwelling.
  • Detached accessory dwelling unit. The minimum size is 150 sq. ft. The minimum dimension of any habitable room, except kitchens, is 7 feet in any horizontal direction (CA Residential Code R304.2).  The minimum ceiling height shall comply with the CA Residential Code. The maximum floor area is 850 sq. ft. Any detached accessory dwelling unit exceeding 650 sq. ft. shall not exceed 50 percent of the existing living area of the main dwelling.
  • Junior accessory dwelling unit. The minimum size of habitable rooms, except kitchens, is 70 sq. ft. (CA Residential Code R304.1). The minimum dimension of any habitable room, except kitchens, is 7 feet in any horizontal direction (CA Residential Code R304.2).  The minimum ceiling height shall comply with the CA Residential Code.  The maximum floor area is 500 sq. ft. and all applicable residential zoning district requirements regarding coverage and floor area ration shall be met.
  • Efficiency dwelling unit.  The habitable room shall be not less than 150 s.f. of floor area with a minimum horizontal dimension in any direction of 7 feet. Bathrooms, toilet rooms, closets, halls, storage or utility spaces and similar areas are not considered habitable rooms. The minimum dimension of any habitable room, except kitchens, is 7 feet in any horizontal direction (CA Residential Code R304.2).  The minimum ceiling height shall comply with the CA Residential Code. The maximum floor area of an efficiency dwelling unit is 500 s.f.

Each accessory dwelling unit, junior accessory dwelling unit, and efficiency dwelling unit shall comply with the height limitations established in the zoning district where the structure is located. Detached accessory dwelling units shall be limited to a single story and shall comply with height restrictions for accessory structures. Attached accessory dwelling units shall comply with height restrictions for primary structures.

See the Accessory Dwelling Unit Requirements.

For additional information or to discuss a particular location, contact the Planning Department.

 

Close window