Development Standards for ADUs

Zoning Regulations

Maximum Size (Floor Area): The maximum size of an ADU:

  • Detached: Detached ADUs cannot exceed a total of 1,200 square feet. If the unit is greater than 800 square feet, lot coverage must be maintained.
  • Attached: Attached ADUs may be up to 60% of the size of the primary dwelling, with a maximum size of 1,200 square feet. Regardless of the size of the primary home, an attached ADU with no more than 1 bedroom may be up to 850 square feet.  An attached ADU with 2 or more bedrooms may be up to 1,000 square feet.  

Lot Coverage: Lot coverage is the amount of your property that may be covered with structures. ADUs 800 square feet or less are exempt from lot coverage requirements and ADUs larger than 800 square feet must meet the lot coverage requirements. Allowed lot coverage ranges from 30% coverage to 50%, depending on the property’s zoning.  To find out the zoning of your property, submit a zoning request on-line.

Setbacks (Distance from property line): Structures are required to be located a certain distance (in feet) from the property line. The required setback for an ADU is as follows:

  • Conversion of existing space: No additional setback is required if you are converting a legally built structure into an ADU.  
  • Newly constructed detached unit:  A minimum of 4-foot side yard and rear yard setback.  Note:  In some cases a setback may need to be larger than the minimum required due to easements for utitlies, drainage, access, etc.
  • Attached ADU:  A minimum of five foot side yard setback and a 20 foot rear yard setback.  In some cases, the rear yard setback for attached units may be reduced to 10 ft.  If your project requires a reduced rear yard setback, contact the Planning Division at (916) 727-4740 to see if your property qualifies.
  • If the ADU is proposed in the front of primary residence or along a street side of a property, the setbacks shall meet the requirements of the property’s zoning.

Maximum Height: 16 feet for a detached unit and 30 feet for an attached unit.

Parking: No additional parking is required for an ADU.

Density: ADUs are exempt from density calculations.