Accessory Structures in Union City, CA (2026)
5 verified accessory structures rules for Union City, California, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
Union City regulates accessory dwelling units under UCMC Chapter 18.34 (Ordinance 900-22), implementing California state ADU law. ADUs are approved ministerially without a hearing, no owner-occupancy is required for ADUs, and up to two ADUs are allowed on a single-family lot.
Union City ADU Rules: Ministerial Permits, No Owner-Occupancy
Few RestrictionsShed Rules
Union City regulates detached accessory structures such as storage sheds under UCMC Chapter 18.32. Sheds under 120 square feet with no utilities need no permit, while larger sheds require building or planning permits, and all must meet setback and height limits.
Union City Shed Rules: Permits, Setbacks, Height Limits
Some RestrictionsGarage Conversions
Union City allows converting an existing garage into an accessory dwelling unit under UCMC Chapter 18.34. The conversion is reviewed ministerially with a building permit, and the city cannot require replacement of the off-street parking spaces lost to the conversion.
Union City Garage Conversion Rules Under ADU Law
Few RestrictionsCarport Rules
Union City treats detached carports as accessory structures under UCMC Chapter 18.32. Carports must sit on the rear half of the lot, meet four-foot side and rear setbacks, and stay within the 12-foot height limit, with permits required above small sizes.
Union City Carport Rules: Setbacks and Accessory Limits
Some RestrictionsTiny Homes
Union City has no standalone tiny-house ordinance. A tiny home on a permanent foundation is reviewed as an accessory dwelling unit under UCMC Chapter 18.34, while a tiny home on wheels is treated as a recreational vehicle and cannot be a permanent residence.
Union City Tiny Home Rules: ADU Pathway Required
Some RestrictionsLooking for Alameda County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Union City city rules.
Accessory Structures in Alameda County →