Dublin, CA Accessory Structures: ADU Rules (2026)

010 states the chapter's purpose is to 'implement Government Code Sections 66310 through 66342 by allowing the creation of accessory dwelling units and junior accessory dwelling units through ministerial review,' language updated by Ordinance 9-25 in November 2025 to track the current state statute numbering. 020 confirms ADUs never count toward a lot's allowed density and that unrelated nonconforming conditions can't be forced as a condition of ADU approval. 030 sets a 60-day deemed-approved clock: a complete application for a lot with an existing residence must be approved or denied within 60 days, and if the City misses that window the permit is automatically deemed approved; a denial must come with written, itemized comments on how to fix the application.

040 lays out the development standards: ADUs are allowed on any size lot with a single-family or multifamily use in the A, R-1, R-2, R-M, and C-1 districts and in Planned Development districts, where this chapter overrides any stricter PD standard. A new detached ADU tops out at 1,200 square feet and 16 feet in height, rising to 18 feet (plus 2 feet for a matching roof pitch) within a half-mile of a major transit stop; required setbacks cap at four feet from side and rear lines, and drop to zero for a unit replacing an existing structure in place.

Only one off-street parking space per unit is required, and it's waived entirely in six listed circumstances, including transit proximity and garage conversions. The chapter is explicit that where it conflicts with the Government Code, the Government Code wins.