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Woodside, California: ADU Regulations

City or County:

Woodside, California

Date Updated:



Attached: SCP/RR/SR/R-1/CC/MFRD

Detached: SCP/RR/SR/R-1/MFRD

Types of ADUs:

Attached, detached, barn conversion, and junior ADU


Must adhere to underlying zoning district regulations.

Owner Occupancy:

Required for Junior ADUs.

Lot Size:

Attached: must meet zoning requirements.

Detached: must meet zoning requirements, except in R-1 districts where min. lot area is 20,000 sq.ft. Two ADUs max per parcel allowed.

For lots smaller than 1 acre, one attached or detached ADU is allowed, and one junior.

For lots larger than 1 acre but smaller than 1.5 acres, one attached and one detached ADU are allowed.

For lots larger than 1.5 acres, two ADUs (attached or detached) are allowed.

Maximum ADU Floor Area:

Attached: not exceed 50% of main residence, or 1,500 sq.ft., whichever is less.

Detached: 1,500 sq.ft. max.

Within a barn: no greater than 50% of barn footprint or 1,200 sq.ft, whichever is less.

Junior ADU: no more than 500 sq.ft.

Note: If an ADU only has the minimum 4’ side and rear setbacks, then it will be limited to 800 sq.ft.

Lot Coverage:

The requirements of § 153.049 related to accessory buildings shall apply.




No min/max


ADUs require separate kitchen facilities (permanent range, counters, refrigerator, sink).

Efficiency ADUs may have an efficiency kitchen which includes a cooking facility with appliances, and a food preparation counter and storage cabinets of a reasonable size in relation to the size of the Junior ADU.


ADUs require separate bathroom facilities.

Junior ADUs may contain separate or may share sanitation facilities with existing dwelling.

Note: Drainage and sewer connections should be assessed on a project by project basis.


One parking space per ADU. Off-street parking to be permitted in setback areas in locations determined by the Town, or through tandem parking, unless specific findings are made that parking in setback areas or tandem parking not feasible based upon specific site, regional, topographic, or fire and life safety conditions. State parking exceptions apply (public transit, historic district, no permits for ADU occupants, car share, attached/conversion/junior)


Attached, Detached: 4’ side and rear. Front are subject to requirements of the underlying district.
When there are two ADUs on site, only one unit may have a side or rear of 4’.
Garage conversion: 4’

Note: Fire Department regulations should be assessed on a project by project basis.


17' maximum


Must be subordinate to main dwelling and approved by Planning Director.


Automatic sprinklers required for barn ADUs and the barn itself.

Rear Yard Coverage:

The requirements of § 153.049 related to accessory buildings shall apply.


The Planning Director to be required to find that ADUs compatible with neighboring property and uses in height, bulk, location, appearance, color, materials, and landscaping. Barn ADUs must be separated from other portions of the barn with a one-hour firewall, in accordance with the Town’s Building Code.

Note: Historic Neighborhoods or Districts should be assessed on a project by project basis.


An efficiency accessory dwelling unit shall include a separate entrance from the main entrance to the structure, with an interior entry to the main living area. For garage conversion ADUs, a new access stair built a minimum of 5’ from rear and side property lines, or existing setback (whichever is greater) for the ADU built above the garage is allowed.

Source Code:

Important Note: Rules and regulations are updated and changed frequently. It’s one of our jobs to be up to speed and navigate those regulations. Let us know if our website isn’t up to date or if you have any information that could help. Cheers!