Monte Sereno CA ADU Regulations


R-1-8 | R-1-20 | R-1-44  

Lot Size:

8,000 sq. ft. minimum

ADU Floor Area:

Attached* maximums: R-1-8, 600 sq. ft. | R-1-20, 700 sq. ft. | R-1-44, 800 sq. ft.

Detached maximums: R-1-8, 900 sq. ft. | R-1-20, 1,000 sq. ft. | R-1-44, 1,200 sq. ft.

*Attached ADUs shall not exceed 50% of existing living area

No. of Bedrooms:  



No min/max


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


At least one uncovered parking space shall be provided for the accessory dwelling unit in addition to the parking required for the main dwelling unit.  Some exceptions apply.  See Section 10.06.140 (E) for exceptions.


A detached accessory dwelling units shall comply with the setback requirements for an accessory structure of the applicable zoning district.


A detached accessory dwelling unit shall comply with the structural and impervious coverage limits of the applicable zoning district, as well as the height requirements for a primary structure.


Attached ADUs can be on either the ground floor or second story of primary dwelling but cannot have direct access to the primary dwelling. Detached ADUs must be located at least 6' from primary dwelling.

Rear Yard Coverage:

Must follow requirements established by the zoning district in which the lot is located.

Materials/ Design:

Accessory dwelling units shall be constructed with the materials identical in color, texture, and appearance to the primary dwelling, including but not limited to, roofing, siding, windows, and doors; and, the dwelling unit shall match the roof pitch and roof form of the primary dwelling so as to blend with the existing architecture.


Attached ADUs must have separate exterior entry.

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