ADU rules in Castro Valley, CA — also called accessory dwelling unit regulations or granny flat ordinances — cover setbacks, owner-occupancy, parking, and permit requirements.
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.
Alameda County updated its ADU regulations to align with California's strong state-level ADU laws. Key provisions: one ADU + one JADU (junior ADU within the main house) ministerially permitted on any single-family lot; detached new construction ADUs up to 1,200 sq ft; attached ADUs up to 50% of the primary dwelling's living area or 1,200 sq ft; 4-foot side/rear setback; one parking space required (but waived if within 1/2 mile of transit); owner-occupancy not required (paused statewide through 2025); ADUs may NOT be used as short-term rentals (under 30 days). Castro Valley has the highest ADU production in unincorporated Alameda County.
STR violations on ADUs trigger §6.65 nuisance proceedings. Unpermitted ADU construction: stop-work + permit-after-the-fact at doubled fees plus potential demolition order.
Other ordinances people look up for this city. Green dot = verified primary-source excerpt.
Castro Valley, CA
Alameda County Code §6.60.050 prohibits repairing, rebuilding, modifying or testing vehicles in residential areas between 7 p.m. and 7 a.m. if it produces so...
Castro Valley, CA
Alameda County Code §6.60.050 limits use of electric or gas leaf blowers, sweepers, vacuums, mowers, trimmers, edgers and hedgers in residential areas to 7 a...
Castro Valley, CA
Alameda County Code §5.08.060 makes it unlawful for any person owning, keeping, or having custody of a dog or other animal to knowingly permit or suffer that...
Castro Valley, CA
Alameda County Code §6.60.080 exempts construction activity from Chapter 6.60 only if it occurs between 7 a.m.-7 p.m. on weekdays and 8 a.m.-5 p.m. on Saturd...
Castro Valley, CA
Castro Valley is unincorporated and operates under Alameda County Code Chapter 6.60 (Noise). §6.60.050 makes it a violation to operate any sound-producing de...
Castro Valley, CA
Heavy commercial vehicles - generally over 10,000 lbs GVW or 22 feet long - cannot be parked overnight on Castro Valley residential streets, and cannot be pa...
Side-by-side rule comparisons with other cities in Alameda County.
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