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San Jose, California: ADU Regulations

City or County:

San Jose, California

Date Updated:




PD districts subject to approved development standards.

Types of ADUs:

Attached, detached and garage conversions


Single-story and two-story ADUs permitted

Lot Size:

3,000 sq.ft. min.

Maximum ADU Floor Area:

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


3,000 to 5,444 sq.ft. lot, 600 sq.ft. ADU

5,445 to 9,000 sq.ft lot, 700 sq.ft. ADU

9,001 to 10,000 sq.ft. lot, 800 sq.ft. ADU

>10,001 sq.ft. lot, 900 sq.ft. ADU

Lot Coverage:

Cannot exceed 40% of yard.


2-bedroom ADU is allowed for units of 800 sq.ft. or greater, otherwise ADU can have only one bedroom or a studio layout. Bedrooms shall not exceed 400 sq.ft.


60 sq.ft. max for entire unit.


Require separate kitchen facilities (permanent range, counters, refrigerator, sink).


Require separate full bathroom. Max 1 bathroom.

Note: Drainage and sewer connections should be assessed on a project by project basis.


1 space required for ADU occupants unless the property qualifies for an exemption under State law. If a garage has been converted, the main dwelling parking space must be replaced, as uncovered or in front or side setback areas. The homeowner may apply for a reduction of one space of required parking. Parking spaces may be configured on-site per state law.


ADUs are subject to the setback requirements for a one-family dwelling in the zoning district in which the one-family dwelling is located, as set forth in this chapter except as follows:

  1. Attached: Same setback requirements as apply to the main house
  2. Detached: 60 feet from front property line, 3 feet rear and side. For second story, 5 feet from both rear and side.
  3. Corner lots: 10 feet on street side.
  4. Lots ½ acre of greater along riparian corridors: 100 feet.
  5. Distance of street curb to all portions of ADU cannot be greater than 200 feet.


If the main house as fire sprinklers, the ADU must have them, as well. If the project is an attached ADU greater than 500 sq. ft. AND the overall gross floor area with the main house exceeds 3,600 sq. ft., then fire sprinklers are required for the entire house and ADU. Sprinklers may be required for a detached ADU that is built with less than a three-foot setback.

All exterior walls of ADU must be within 400 feet of a fire hydrant. Fire hydrants must have a minimum flow of 1,000 gpm at 20 psi.

Note: Fire Department regulations should be assessed on a project by project basis.


Attached: must comply with standards of underlying zoning district.

Detached single-story: 18 ft. max

Detached two-story or 2nd story over garage: 24 ft. max


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 garage meets Building and Fire Code; but not be attached to other accessory buildings.

Rear Yard Coverage:

Cannot exceed 40% of yard.


Detached units do not need to meet any specific design standards, provided there is visual compatibility with existing primary dwelling. Attached ADUs and detached ADUs on properties listed on the Historic Resources Inventory must incorporate architectural style and elements of the primary dwelling.

Note: Historic Neighborhoods or Districts should be assessed on a project by project basis.


Door cannot be on the 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.

Tree Removal:

If building an ADU requires removal of an ordinance-size or heritage tree, then must obtain a tree removal permit.

Source Code:

Important Note: Rules and regulations are updated and changed frequently. It’s one of our jobs to be up to speed and navigate those regulations. Let us know if our website isn’t up to date or if you have any information that could help. Cheers!