San Mateo County, CA Parking Rules: Overnight Parking (2026)

There is no countywide ordinance prohibiting all overnight street parking in unincorporated San Mateo County. Instead of a flat overnight ban, the County regulates specific vehicle types and locations. 070, the Board of Supervisors may restrict oversized vehicles over six feet high from designated residential streets and trailers of any size from designated public streets at all hours, which effectively limits overnight parking of RVs, large trucks, and trailers wherever those restrictions have been posted. 030: it is unlawful to park a commercial vehicle for more than one hour on a street in a residential zone in the unincorporated area, except when actively transacting lawful business there or when temporarily disabled, so overnight commercial parking in residential neighborhoods is generally not allowed.

For passenger vehicles on streets without a posted limit, the operative overnight constraint is the state 72-hour rule (California Vehicle Code Section 22651(k)). Because individual roads can carry their own Board-approved restrictions, drivers should check for posted signs and curb markings; the County Department of Public Works installs such restrictions only after Board approval.