South San Francisco, CA Property Maintenance: Garage Sale Rules (2026)

No San Mateo County ordinance specifically regulating residential garage or yard sales in the unincorporated area could be identified from the County's published code or its Planning and Building pages. (Note: widely circulated 'last full weekend of the month plus two registered sales per year' rules belong to Los Angeles County's Department of Regional Planning, not San Mateo County, and should not be applied here.) Absent a dedicated rule, an occasional garage sale at a residence is generally treated as an incidental, accessory residential use rather than a regulated commercial activity. Sellers should still observe the County's general standards: sales and their signage must not create a public nuisance, obstruct sidewalks, streets, or sight lines, or violate the County's sign and zoning regulations, all of which the Planning and Building Code Compliance Section enforces in the unincorporated area. Temporary off-site or right-of-way signs may be restricted, and merchandise or vehicles should not block the public right-of-way. Because the County does not appear to license garage sales, residents do not have a confirmed registration or permit obligation; however, frequent or continuous selling could be viewed as an unpermitted commercial use of a residential property. Residents in doubt should contact the Planning and Building Department to confirm current requirements before holding repeated sales.