City Regulations

  • Unincorporated properties include cities that do not have their own departments and codes, therefore use the regulations of the county.

    • Max number of ADUs:

      • Conversion ADUs: Up to 25% of existing units (e.g., a 20-unit building can have 5 ADUs, with 2 possibly detached).

      • New Construction Detached ADUs: Up to 2 additional ADUs.

    • Max size of ADUs:

      • Attached and detached are subject to max unit sized of 850 square ft. (one bedroom or less) or 1,200 square ft. (more than one bedroom)

      • All addition ADUs over 800 square ft. on single family-dwellings may not exceed 50% of primary living area

    • Max height of ADUs:

      • Detached ADU:

        • 16 ft. (one-story) or 18 ft. (two stories) if within 0.5 miles of major transit stop or high-quality transit corridor.

        • Additional 2 ft. for matching roof pitch of primary dwelling.

      • Attached ADU: Same height and setbacks as primary dwelling (80% second-story rule applies).

    • Setbacks:

      • 4 ft. for all new construction

      • Detached ADUs over 800 square ft must have a min 6 ft. separation from other structures.

    Alameda County ADU handbook

    • Max Number of ADUs:

      • 1 ADU allowed on single-family dwellings

      • Depending on specific zoning, the number of ADUs may change for duplex/multi-family dwellings

    • Max Size:

      • Up to 850 square ft. for studio/1-bedroom

      • Up to 1,000 square ft. for 2+ bedrooms

    • Max Height:

      • Detached ADU:

        • 20 ft. (unless on hillside overlay)

      • Attached ADU:

        • 25 ft.

    • Setbacks:

      • 4 ft. for rear, interior side, and street side (unless on hillside overlay)

    City of Berkeley ADU standards

  • Unincorporated properties include cities that do not have their own departments and codes, therefore use the regulations of the county.

    • Max Number of ADUs:

      • N/A

    • Max Size:

      • Detached ADUs:

        • Up to 1,000 square ft. in any zoning district, unless the lot is 12,000 square ft. or more, or in an agricultural district, where the limit is 1,200 square ft.

        • Kensington (-K) combining district: Up to 850 square ft. for 1-bedroom, up to 1,000 square ft. for 2+ bedrooms.

      • Attached ADUs:

        • Up to 1,000 square ft. in any zoning district, unless the lot is 12,000 square ft. or more, or in an agricultural district, where the limit is 1,200 square ft.

        • Kensington (-K) combining district: Up to 850 square ft. for 1-bedroom, up to 1,000 square ft. for 2+ bedrooms.

        • May not exceed 50% of the living area of the primary dwelling unit, except to permit an ADU of 850 square ft. for 1-bedroom, or 1,000 square ft. for 2+ bedrooms.

      Max Height:

      • Must comply with all requirements relating to building height that are generally applicable to residential construction in the zone.

      Setbacks:

      • 4 ft. from the side and rear lot lines.

    Contra Costa ADU handbook

    • Max. Number of ADUs:

      • One ADU or JADU per lot is allowed for single-family dwellings. For multifamily dwellings, up to 25% of existing units can be converted to ADUs, with a minimum of one ADU allowed.

      • Additional options include up to two detached ADUs for lots with existing multifamily dwellings and one detached ADU for single-family dwellings.

    • Max. Size for ADUs:

      • Detached: 1,200 square ft.

      • Attached: 50% of existing dwelling, or no size limit if new building

    • Max. size for ADUs:

      • Detached ADUs: Height is limited to 16 ft.

      • Attached ADUs: Subject to zoning height limits; new buildings or additions may have different restrictions

    • Setbacks:

      • 4 ft.

    Los Angeles ADU handbook

  • Unincorporated properties include cities that do not have their own departments and codes, therefore use the regulations of the county.

    • Max. Number of ADUs:

      • Multi-Family Dwellings:

        • Attached ADU:

          • Minimum 1 ADU and maximum 25% of multi-family units, converted from existing space; and 1 new construction ADU.

        • Detached ADUs:

          • Maximum 2 ADUs per property.

      • Single-Family Dwellings

        • 1 Attached ADU and 1 Detached ADU.

    • Max. Height of ADUs:

      • 25 ft. or as specified by CSD/ Specific Plan, whichever is less.

    • Max. Size of ADUs:

      • Attached ADUs:

        • 50% of existing primary structure or 1,200 square ft., whichever ir less. (Minimum. 800 square ft.)

      • Detached ADUs:

        • Multi-Family Dwellings:

          • No maximum.

        • Single-Family Dwellings:

          • 1,200 square ft.

      • Conversion ADU:

        • No Maximum.Up to 150 square feet can be added for ingress/egress

    • Setbacks:

      • 4 ft. side and rear setbacks.

    LA County ADU Handbook

    • Max. Number of ADUs:

      • 1 per lot for Single-Family dwellings.

      • No more than 2 per lot for multi-family (limit may change based on ADU category).

    • Max. Size for ADUs:

      • 850 square ft.. for studio or one-bedroom; 1,000 sf. for 2-bedrooms or more.

    • Max. Height for ADUs:

      • 18 ft. or established by base zone.

    • Setbacks:

      • 4 ft., or the regularly required setbacks (no less than 3 ft.).

    City of Oakland ADU handbook

  • Unincorporated properties include cities that do not have their own departments and codes, therefore use the regulations of the county.

    • Max. Number of ADUs:

      • 1 ADU per property

    • Max. Height of ADUs:

      • 16 ft.

    • Max. Size of ADUs:

      • Attached ADUs:

        • Up to 50% of the area of the primary dwelling unit, to a maximum of 1,200 square ft.

      • Detached ADUs:

        • 1,200 square ft. maximum within building site area, 800 square ft. maximum within the setback area where permitted.

    • Setbacks:

      • 4 ft. side and rear-setbacks. Front setbacks are not permitted.

    Orange County ADU Handbook

    • Max Number of ADUs:

      • 2 ADUs on a lot with an existing structure

    • Max Size:

      • Up to 1,200 sq. ft. for ADUs

    • Max Height:

      • Detached ADUs:

        • 16 ft. (additional requirements based on specific zones)

      • Attached ADUs:

        • 25 ft.

    • Setbacks:

      • Front Yard: 20 ft.

      • Side Street Yard (corner): 12.5 ft.

      • Side and Rear Yard: 4 ft.

    City of Sacramento ADU handbook

  • Unincorporated properties include cities that do not have their own departments and codes, therefore use the regulations of the county.

    • Max Number of ADUs:

      • Single-family parcels:

        • 1 ADU, attached or detached

      • Multi-family residential or duplex parcels:

        • Up to 2 new-construction detached ADUs

        • Up to 25% of total unit count in ADUs converted from existing non-living space

    • Max Height of ADUs:

      • Detached ADUs:

        • 16 ft.

        • 18 ft. if located within ½ mile of major transit stop or to allow a roof pitch consistent with the primary dwelling

        • 20 ft. if setback a minimum of 10 ft. from the rear property line and 5 ft. from the side property line

        Attached ADUs:

        • 25 ft.

        ADUs in Multifamily:

        • 18 ft.

    • Max Size of ADUs:

      • Detached ADUs:

        • 1,200 square ft.

        Attached ADUs:

        • 50% of the habitable square footage of the primary dwelling, or 800 square ft., whichever is greater

    • Setbacks for ADUs:

      • Front Yard:

        • 20 ft.

        Side Street Yard (corner):

        • 12.5 ft.

        Side and Rear Yard:

        • 4 ft.

    Sacramento County ADU handbook

  • San Francisco offers three options for ADU regulations: State, Hybrid, and Local.

    1. State

    • For Single-Family Dwellings:

      • Max number of ADUs:

        • 1 converted ADU

        • 1 detached ADU

        • 1 attached ADU

      • Max. Size:

        • Up to 850 sq. ft. for 1-bedroom

        • Up to 1,000 sq. ft. for 2+ bedrooms

        • Up to 50% of the existing primary dwelling size for attached ADUs

      • Max. Height:

        • Attached ADU: 25 ft.

        • Detached ADU:

          • 18 ft. (within 0.5 miles of a transit stop or corridor)

          • 16 ft. (otherwise)

      • Setbacks:

        • 4ft. side and rear setbacks

    • For Multi-Family Dwellings:

      • Max Number of ADUs:

        • 1 converted ADU

        • 1 attached ADU

        • 1 detached ADU

      • Max Size:

        • For Attached ADUs:

          • Up to 850 sq. ft. for studios and 1-bedroom (or 50% of existing primary dwelling, whichever is greater)

          • Up to 1,000 sq. ft. for 2+ bedrooms (or 50% of existing primary dwelling, whichever is greater)

        • Detached ADUs:

          • Up to 850 sq. ft. for studios and 1-bedroom

          • Up to 1,000 sq. ft. for 2+ bedrooms

      • Max Height:

        • For Attached ADUs:

          • 25 ft.

        • Detached ADUs:

          • 18 ft. if within 0.5 miles of a transit stop or corridor

          • Additional 2 ft. for roof pitch alignment with primary dwelling

          • 18 ft. if on a lot with a multi-family, multi-story dwelling

          • 16 ft. otherwise

      • Setbacks:

        • 4 feet from side and rear lot lines

    1. Hybrid

    • For Single-Family Dwellings:

      • Max Number of ADUs:

        • 1 ADU (either attached or detached)

      • Max Size:

        • Detached ADU: Up to 800 sq. ft.

      • Max Height:

        • Detached ADU:

          • 18 ft. (within 0.5 miles of a transit stop or corridor)

          • 16 ft. (otherwise)

      • Setbacks:

        • 4 feet from side and rear lot lines

    • For Multi-Family Dwellings:

      • Max Number of ADUs:

        • 2 detached ADUs

        • 1 converted ADU or up to 25% of the existing legal dwellings within the structure

      • Max Size:

        • N/A

      • Max Height:

        • 18 ft. if within 0.5 miles of a transit stop or corridor

        • Additional 2 ft. for roof pitch alignment with primary dwelling

        • 18 ft. if on a lot with a multi-family, multi-story dwelling

        • 16 ft. otherwise

      • Setbacks:

        • 4 feet from side and rear lot lines

    1. Local

      • Max Number of ADUs:

        • Converted and Attached ADUs:

          • If 4 or fewer legal dwelling units are on the lot: 1 ADU is allowed

          • If 5 or more legal dwelling units are on the lot: Unlimited ADUs are allowed

        • Detached ADU:

          • 1 ADU is allowed

      • Max Size:

        • For Converted and Attached ADUs:

          • Based on available building area

        • Detached ADUs:

          • Up to 850 sq. ft. for studios and 1-bedroom

          • Up to 1,000 sq. ft. for 2+ bedrooms

      • Max Height:

        • For Converted and Attached ADUs:

          • Based on zoning district

        • Detached ADUs:

          • 16 ft.

      • Setbacks:

        • Converted and Attached ADUs:

          • Depends on zoning district

        • Detached ADUs:

          • 4 feet from side and rear lot lines

    City of San Francisco ADU handbook

  • One can choose to follow either State code or City code when designing an ADU.

    • City

      • Max. Number of ADUs:

        • 1 attached or detached.

      • Max. Size for ADUs:

        • For lots less than 9,000 sq ft; 1,000 sq ft limit. Otherwise, 1,200 sf for detached ADU and 50% of main home & no more than 1,200 sf for attached ADU.

      • Max. Height for ADU:

        • 25 ft.

      • Setbacks:

        • 4ft.

    • State

      • Max. Number of ADUs:

        • 1 attached or detached and one conversion for Single-Family Dwellings.

        • 2 attached or detached ADUs and 1 or up to 25% of existing units in conversion ADU for Multi-Family Dwellings.

      • Max. Size for ADUs:

        • 800 sq ft

      • Max. Height for ADUs:

        • 18 ft

      • Setbacks

        • 4 ft.

    San Jose ADU handbook

    • Max Number of ADUs:

      • Single-family parcels:

        • 1 detached ADU

        • 1 attached ADU

        • 1 converted ADU.

      • Multi-family and mixed-use parcels:

        • Up to 2 detached ADUs

        • additional attached ADUs up to 25% of existing dwelling units

        • 1 converted ADU.

    • Max Height of ADUs:

      • Detached ADUs: 25 ft.

      • Attached ADUs: 25 ft.

    • Max Size of ADU:

      • Detached ADUs: 1,200 square ft. (on parcels greater than 5,500 square feet).

      • Attached ADUs: 1,000 square ft. or 50% of main unit size (whichever is less).

    • Setbacks for ADUs:

      • 4 ft. rear and corner setbacks, 3 ft. side setbacks.

    City of Santa Clara ADU handbook

    • Max. Number of ADUs:

      • 1 ADU.

    • Max. Height of ADUs:

      • Attached:

        • Depends on zone.

      • Detached:

        • 18ft. plus additional 2 ft. for a roof pitch, or the height of the primary structure, whichever is greater.

    • Max. Size of ADUs:

      • Attached:

        • 50% of primary structure or 1,200 square ft. (whichever is less).

      • Detached:

        • 1,200 square ft.

    • Setbacks:

      • 4 ft. side and rear setbacks.

    Anaheim ADU Handbook