Cupertino ADU Regulations


All properties zoned for single family, multifamily, or mixed-use residential may be eligible to build ADUs.

Number of units

The number of ADUs you’re able to build depends on how your lot is zoned:

  • Lots zoned for single family use may add 1 ADU and 1 Jr. ADU (JADU).
  • Lots zoned for duplex or multi-family may add 1 ADU per 4 existing residential units. No more than 2 detached ADUs are permitted per lot.

Building size

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

  • 500 sq. ft. for a Jr. ADU (JADU)
  • 800 sq. ft. for an ADU, if the home has reached the maximum floor area ratio and lot coverage
  • 850 sq. ft. for studio / 1 bedroom ADUs in single family zoned lots
  • 1,000 sq. ft. for 2+ bedroom ADUs in single family zoned lots
  • 1,200 sq. ft. for detached ADU in multifamily zoned lots

Building height

Detached ADUs can reach a maximum height of 16 feet. Attached ADUs can reach the same height as the main structure, assuming they comply with municipal code (including daylight plane).

A two-story ADU is only allowed if you are converting a portion of an existing second story space into an ADU.


Minimum setbacks of 4 feet from the side and rear lot lines, as well as 6 feet from any existing structures are required for detached ADUs. No setback is required for an ADU that replaces an existing structure and is located in the same location and to the same dimensions as the structure being replaced.


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


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.


While long-term rentals are permitted for ADUs, homeowners may be required to sign a deed restriction preventing short-term rentals (e.g. Airbnb for less than 30 days).