Accessory Dwelling Ordinance

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What is an ADU? | Benefits of an ADUContact

Update on Public Hearing

The scheduled review of the proposed ADU ordinance amendments and adoption process on March 23, 2020, City Council meeting is postponed. To limit opportunities for exposure and to lessen the spread of the COVID-19 virus, the City will reschedule the item for a future public hearing.

How to Apply for an ADU 

To apply for a permit to construct an ADU, fill out the ADU Completeness Checklist and a Building Permit application. 

Having trouble getting started? Visit: for a step-by-step guide to start the design process, apply for permits, guidance through the construction process, and tips for moving-in.  The Second Unit Center is a program of the County of San Mateo’s Home for All initiative providing information and tools to make it easier for homeowners to build second units, to help increase the housing supply in the County. Second Unit Center has developed a Workbook and website to help residents with the process of constructing an ADU, see below:

Second Unit Workbook (English / Spanish)

For more information visit:   

San Mateo County Second Unit "One Stop Shop" Pilot Program

Announcing Bright in Your Own Backyard, San Mateo County’s new Second Unit One Stop Shop. The nonprofit "Hello Housing" will provide up to 100 hours of free feasibility and project management support to participating homeowners who want to add a second unit to their property. The program is now accepting applications from eligible homeowners in East Palo Alto, Redwood City, Pacifica and unincorporated areas of San Mateo County.  

Application deadlines apply, so learn more about the Second Unit One Stop Shop today and submit your application at or call (415) 446-9235. Applying is free and simple.  

The Bright in Your Own Backyard is an innovative collaboration among Hello Housing, local government, and homeowners to build more second units in our communities.

2020 Amendments

New State housing laws that went into effect on January 1, 2020, grant more flexibility to construct Accessory Dwelling Units (ADU) across California. Redwood City is in the process of updating its local ADU ordinance to be compliant with State regulations. The Planning Commission and City Council held a Joint Study Session on February 10, 2020 to discuss the new State ADU regulations and the required considerations for adopting a local ordinance. No formal action took place at the meeting - see video of the meeting here  

In the interim, the City will review ADU projects under the State ADU regulations. Below is a summary of new changes to the State ADU law.

Development Standards

  • Cities are required to allow junior accessory dwelling units (JADUs). These are units of up to 500 square feet of converted space contained entirely within a single-family home. A JADU may share a bathroom with the existing home.
  • ADUs will be allowed in multi-family units. Conversion of uninhabited spaces, including garages, will be allowed for at least one ADU or up to 25% of units in multi-family buildings. Plus, up to two detached ADUs with 4-foot setbacks will also be allowed.
  • Cities must allow a minimum of 850 square feet for a one-bedroom ADU, or 1,000 square feet for an ADU with more than one bedroom.
  • Cities are prohibited from implementing any lot coverage, floor area ratio, and/or open space requirements for detached ADUs.

 Process Updates

  • Cities may not impose impact fees on ADUs less than 750 square feet. 
  • There is a 5-year moratorium on local owner-occupancy restrictions.
  • Mandatory 5-year stay of enforcement on unpermitted ADUs, if they meet health and safety standards.
  • Short-term rentals of ADUs or JADUs are not permitted.
  • California Department of Housing and Community Development (HCD) & the Attorney General can enforce compliance if a new local ordinance is out of compliance, but it provides a 30-day right to sure or state findings to support the local ordinance.

For more information and a full list of new State ADU laws, go here. (Provided by the San Mateo County Department of Housing)


What is an Accessory Dwelling Unit?

An Accessory Dwelling Unit (ADU) is a smaller living unit on a property that has a single-family residence. It is complete with its own kitchen and bathroom facilities.  Common names for an ADU include in-law unit, secondary unit, and backyard cottage. ADUs are not allowed to be used exclusively as a short-term rental unit.

Benefits of an ADU

  • Extra living space for family or guests
  • Housing for aging parents, caregivers or adult children
  • Efficient use of existing infrastructure
  • Rental income



Apollo Rojas
Senior Planner
(650) 780-7365

PC Notice 10.06.15