All ADU Regulations

Mountain View, California

Mountain View has updated its ADU ordinance to comply with new state laws. Below are the up-to-date requirements for permitting an ADU in Mountain View.

October 28, 2020
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All properties zoned for single family, duplex or multifamily use 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 multi-family may add 1 interior conversion ADUs per 4 existing residential units 2 detached ADUs.

Building size

Maximum square footage is determined by your ADU type:

  • 500 sq. ft. for a Jr. ADU (JADU)
  • 800 sq. ft. for an ADU if you have reached the maximum lot coverage or floor area ratio for the lot
  • 850 sq. ft. for a 1 bedroom ADU
  • 1,000 sq. ft. for a 2+ bedroom ADU
  • An attached ADU may not exceed 50% of the existing living area

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).


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 JADUs, studio ADUs on single family zoned lots, and ADUs on multi family lots. When converting a garage or carport, replacement parking is not required.

For 1+ bedroom ADUs on single family zoned lots, one space (including parking in a driveway) is required, unless the property is within 0.5 miles walking distance of public transportation (including a bus stop).


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).


Do you have a utility easement over your property? Do you have special setbacks? Reach out to us and we’ll help you build a custom ADU to fit your unique property characteristics and local regulations!

Design and build with confidence.