Sunnyvale, CA Accessory Structures: ADU Rules (2026)

040 sets the general requirements applying to every ADU in the city. Each unit must have at least 150 square feet of interior area, measured from the outside dimensions of the building or wall. Detached ADU height is capped at 16 feet on a typical single-family or single-story multifamily lot, 18 feet on a lot within a half mile of a major transit stop or high-quality transit corridor (with two more feet allowed to match the primary dwelling's roof pitch), and 18 feet on a lot with an existing or proposed multistory multifamily building; attached ADUs are capped at 25 feet or the height limit of the main building, whichever is lower.

ADUs are limited to a maximum of two stories, and no off-street parking spaces are required, nor must an applicant replace any covered parking removed to build the unit. A detached, non-streamlined ADU must sit at least five feet from the main building, and side and rear setbacks are a minimum of four feet unless the new ADU reuses the same footprint as a demolished structure. 72. An ADU may be rented separately from the main dwelling but cannot be sold or conveyed separately from the other units on the lot, except as state law under Government Code Section 66341 allows.