San Jose, CA

Last Update Dec-2020

Below are the up-to-date requirements to permit an ADU in San Jose, CA.

Zoning

All properties zoned for single family or multi-family with the following zoning codes are eligible for ADUs.

  • R-1 (most single family homes)
  • R-2, R-M (duplexes & multi-family)
  • PD (planned development)

Building size

Maximum building size is determined by your lot size, zoning and ADU type:

Single family zoned lots:

Up to 9,000 sq. ft.:

  • Detached ADU: 1,000 sq. ft. maximum
  • Attached ADU: up to 800 sq. ft. or up to 50% of the primary residence without exceeding 1,000 sq. ft. (e.g. for a 1,800 sq. ft. home, a 900 sq. ft. attached ADU is allowed

9,000 sq. ft. and greater:

  • Detached: 1,200 sq. ft. maximum
  • Attached: up to 800 sq. ft. or up to 50% of the primary residence without exceeding 1,000 sq. ft. (e.g. for a 1,800 sq. ft. home, a 900 sq. ft. attached ADU is allowed

Any lot with an existing JADU:

  • JADU: 500 sq. ft. maximum
  • Detached: 800 sq. ft.
  • Attached: not allowed with a JADU
Duplex & multifamily zoned lots:

Any lot size:

  • Detached: 800 sq. ft.
  • Attached: 800 sq. ft.
  • JADU: not allowed

Building height

Maximum building height depends on the zoning and ADU type:

Single family zoned lots:
  • Attached ADU: same height limitations as apply to the main dwelling unit
  • Detached ADU: One story: 18 ft. maximum; two-story: 24 ft. maximum; if the property already includes a JADU, height of the detached ADU is 16 ft. maximum
Duplex or Multifamily zoned lots:
  • Attached ADU: limited to a conversion of existing non-livable space and must maintain existing height
  • Detached ADU: 16 ft. maximum

Basements

Conversion of existing unfinished basement space can be used for an attached ADU.

Setbacks

Minimum setbacks are determined by the zoning and ADU type. For all corner lots, regardless of zoning type, a 10 ft. setback is required on the street side.

Single family:
  • Attached: same setback requirements as apply to the main home
  • Detached: must be set back 45 minimum from front property line, rear / side setbacks less than 3 ft. may be subject to fire mitigation measures; a 2nd story or new ADU with greater than 40% rear yard coverage must be set 4 ft. back from rear / side property lines.
Duplex or multifamily:
  • Attached: limited to the conversion of existing non-livable space
  • Detached: must be in the rear yard or 45 ft. from the front property line; minimum 4 ft., allows for up to 1 ft. projection for eaves; 2nd story must be 4 ft. set back from rear / side property lines

Parking

No additional parking is required for ADUs. Even when converting a garage or carport, replacement parking is not required.

Owner-occupancy

Owner occupancy is not a requirement for permitting an ADU from January 1, 2020 until January 1, 2025. This is a great opportunity for rental property owners to increase their yields in a cost-effective way.

Rental

While long-term rentals are permitted for ADUs, short-term rentals (e.g. Airbnb for less than 30 days) are not permitted in San Jose.

Watch-outs

Do you have a utility easement over your property? Are you on a lot with special setbacks? A custom ADU might be right for you. Reach out to us and we’ll help you build a custom ADU to fit your unique property characteristics and local regulations!