Dublin, CA Accessory Structures: Garage Conversions (2026)

Dublin treats garage conversions under its Building Code and Zoning Ordinance. The City's accessory-structures guidance notes that offices, living rooms, sleeping areas, and other habitable uses do not qualify as exempt accessory uses, so converting a garage into living space requires a building permit and must meet residential building, energy, and egress standards. The most common path is converting a garage into an accessory dwelling unit (ADU) under Chapter 8.80, which implements California Government Code 66310 et seq. Section 8.80.040 provides that replacement of the off-street parking spaces for the principal dwelling is not required when the ADU is created through the conversion of a garage, carport, or covered parking structure. This is a key state-driven preemption: cities cannot force homeowners to rebuild the lost garage parking when the space becomes an ADU. A garage conversion ADU still must satisfy the ministerial review requirements (approved or denied within 60 days under Section 8.80.030), minimum-size and building-code standards, and a separate entrance. Conversions that simply turn the garage into additional living area of the main house (not an ADU) are governed by the Building Code and applicable zoning, and may need to preserve required covered parking depending on the zoning district. Because conversions involve egress, fire-separation, insulation, and electrical work, plans and a permit are required. Confirm requirements with the Building Division at (925) 833-6620.