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San Jose CA ADU Guidelines

Accessory Dwelling Unit (ADU) City Regulations


R-1/R-2 with only a one-family dwelling on lot.

Lot size:

5,445 sq. ft. minimum

Maximum ADU Floor Area:

Attached:  no more than 50% of primary dwelling floor area

Detached: Less than or equal to 9,000 sq.ft. lot, 600 sq. ft. ADU

9,001 to 10,000 sq. ft. lot, 650 sq.ft. ADU

Greater than 10,000 sq.ft. lot, 800 sq.ft. ADU

Number of Bedrooms:

Studio layout permitted; otherwise one bedroom 400 sq. ft. max.


60 sq.ft. max for the entire unit.


Require separate bathroom and kitchen facilities (Permanent range, counters, refrigerator and sink). Max. 1 bathroom.


One space in addition to required parking spaces for primary dwelling, unless secondary unit qualifies for exemptions.  Must be located on mud-free, dust-free surface, outside of front and side setbacks of property.  ADU parking space may be located within garage driveway apron that is minimum of 18' in length.


Same as the underlying zoning district with the following provisions:

Single-story unit: rear setback can be reduced to 5' if ADU occupies 50% or less of area between 5' and required rear setback.

Attached/above an attached garage: rear and side setback can be 5’.

Garage conversion: if existing legal garage converted to secondary unit, no additional setback required.

Riparian: for ½ acre lots or more, minimum 100' riparian setback is required.


Attached: must comply with standards of underlying zoning district.

Detached: one story, 18' max with 14' average.


Attached: must share wall or have integral roof structure with primary residence, and separated by no more than 10 feet.

Detached: must be in rear yard with 6’ separation from primary dwelling. May be attached to detached garage, if meets Building and Fire Code; but not be attached to other accessory buildings.

Rear Yard Coverage:

Cannot exceed 40% of yard.


Must be constructed with facade materials similar in texture and appearance to primary dwelling, including but not limited to roofing, siding, windows, and doors. Roof pitch and form should match primary dwelling to blend with one-family dwelling architecture.


Door cannot be on same street-facing facade as primary dwelling, unless all other locations for placing front door would require pathway that is unobstructed, clear to the sky and extending from a street to front door.

For more ADU Information:

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