Accessory Dwelling Units (ADUs)

Benefits of Accessory Dwelling Units (ADUs)

Accessory Dwelling Units (ADUs), commonly known as “granny units”, are encouraged by the Town of Woodside.  ADUs create valuable housing opportunities, e.g., housing for domestic helpers and health care aides, aging parents, and adult children; and rental stock. In Woodside, ADUs count as affordable units towards the Town’s allocated share of the region’s total housing needs. Woodside has been successful in meeting its affordable housing needs through the development of ADUs in all of its residential districts.  From 2015 to 2019 (i.e., during the current, State-certified Housing Element cycle of 2015-2023), 47 ADUs were constructed in Town. In 2020, 5 building permit applications were submitted for ADUs; and more were preparing plans for submittal.

2020 Relaxed Regulations

In 2019, the California Legislature passed several bills – specifically Assembly Bill 68, Assembly Bill 881, and Senate Bill 13 – which relaxed the regulation of ADUs.  These bills, which went into effect January 1, 2020, require local agencies to permit up to one ADU and one Junior ADU per lot, subject to specific restrictions.  One of the most significant provisions of these new State laws is the prohibition of regulations that would preclude an ADU of at least 800 square feet, which is 16 feet in height, and with 4-foot side and rear setbacks. The Woodside ADU Ordinance has been updated (Woodside Municipal Code Section 153.211) to comply with State law, and can be viewed at: Municode.

What is an ADU?

An ADU is an attached or detached residential dwelling unit which provides complete independent living facilities for one or more persons; and includes a kitchen and permanent provisions for living, sleeping, and sanitation on the same parcel as the single-family dwelling. 

What is a Junior ADU?

A Junior ADU is an ADU that is no more than 500 square feet in size, is contained entirely within an existing or proposed main dwelling, includes an efficiency kitchen, has a separate exterior entry from the main dwelling, and maintains an interior connection to the main living dwelling.

Attributes of ADUs

All ADUs in Woodside must have a permanent foundation and permanent utilities and are approved via a Building Permit only. ADUs can be attached to the main dwelling, detached, above a garage, in a basement (with proper egress), or within a barn. ADUs can also be created by converting an existing garage. One parking space is required for ADUs with one or more bedrooms (unless a parking waiver applies), and no parking is required for studio ADUs.  ADUs can be up to 1,500 square feet.  ADUs can also be rented for not less than 30 days. 

Number of ADUs Allowed

The following chart lists the number of ADUs allowed by parcel size and zone district:

Parcel Size or Zoning: Number of ADUs Allowed:
Equal to, or greater than, 1.5 acresA maximum of two, whether attached or detached.
Equal to, or greater than, 1.0 acre; but less than 1.5 acresA maximum of one detached and one attached.
Less than 1.0 acreNo more than one, whether attached or detached, and one Junior ADU.
In the R-1 DistrictNo more than one, whether attached or detached, and one Junior ADU.

If you are planning to construct an ADU or JADU, please fill out and submit an Accessory Dwelling Unit Survey Form by email to Sarah Harper.