Check rules for adding an ADU to a building with tenants

If you are building an ADU with the Local program and you have tenants, follow these rules.

These rules only apply to ADUs in the Local program. California state law affects whether we can subject some ADUs to rent stabilization.

Rent Ordinance for new ADUs

Your new units will be subject to the Rent Ordinance if:

  • You are building a Local program ADU
  • You are adding an ADU to an existing building that already has residential units subject to the Rent Ordinance
  • You request a waiver for your project

The Rent Ordinance regulates evictions and rents. See more from the SF Rent Board.

You must register these units with a Regulatory Agreement called a Costa Hawkins Agreement. Here is a template for a Costa Hawkins Agreement.


Depending on your property and ADU plans, you may need a Waiver to build your ADU. A waiver is an exception to a Planning Code requirement.

For ADUs added to existing buildings, we grant waivers or partial waivers for requirements for:

  • Density (or the amount of residential units on a property)
  • Open space (or the amount of outdoor useable space per unit)
  • Rear yard (or the amount of back yard)
  • Exposure (or the amount of windows that a unit has or amount of open area that it’s facing onto)

For ADUs added to new constriction, we grant waivers for density requirements only. 

We do not grant waivers for ceiling height, ventilation, fire safety, and exits. These are Building Code requirements.

Housing services

If your property currently has tenants, you must get permission from your tenants to remove housing services.

Examples of housing services include:

  • Garage facilities
  • Parking facilities
  • Driveways
  • Storage space
  • Laundry rooms
  • Decks
  • Patios
  • Gardens

See Rent Ordinance Section 37.2(r) for information about the removal of housing services. Call the Rent Board's phone counseling line at (415) 252-4600 if you have any questions.

If you remove housing services by building your ADU

Get permission from your tenants to remove housing services.

You will also need to:

  • Post a notice for 15 days in a common area of the building
  • Mail that notice to all tenants and the property owner

Your notice must state:

  • How many ADUs you are adding
  • Where they will be located
  • What housing services you propose to remove

You must post these notices before you submit your application.

Provide us with a:

  • Copy of the notice
  • Postmarked letter to the owner
  • Photograph of the notice posted in the building
  • Copy of your mailing list

Other activities

You may need to work with the Rent Board on other actions.

Last updated March 03, 2021