Accessory Structures in Castro Valley, CA (2026)
3 verified accessory structures rules for Castro Valley, California, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
Alameda County's ADU ordinance follows California state law (Gov. Code §65852.2) - one ADU and one JADU are ministerially permitted on any single-family lot in Castro Valley. Detached ADUs up to 1,200 sq ft, attached ADUs up to 50% of primary floor area.
Castro Valley Accessory Dwelling Unit (ADU)
Few RestrictionsGarage Conversions
California state law (Gov. Code §65852.2) lets Castro Valley homeowners convert an attached or detached garage into an ADU as a 'by-right' ministerial permit, with no replacement parking required if the garage is converted.
Castro Valley Garage Conversion to ADU
Some RestrictionsLooking for Alameda County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Castro Valley city rules.
Accessory Structures in Alameda County →