Pittsburg, CA Fence Regulations: Retaining Walls (2026)

Retaining walls in Pittsburg are regulated under the California Building Code as adopted by the city and enforced by the Building Division. A building permit is required for any retaining wall exceeding 4 feet in height measured from the bottom of the footing to the top of the wall, OR any wall of any height that supports a surcharge such as a driveway, sloped fill above the wall, or structure load. Walls requiring permits must be designed by a licensed engineer or meet pre-approved prescriptive designs, and structural calculations, geotechnical soils reports (for walls over 6 feet or challenging soils), and drainage plans may be required. Walls within earthquake fault zones or liquefaction zones (relevant along Pittsburg's bay-margin areas) may need enhanced engineering. Drainage behind retaining walls (perforated pipe, gravel, weep holes) is critical to prevent hydrostatic failure. Wall height for fence-purposes is measured from the higher grade side for sight-triangle purposes; combined retaining wall + fence height is capped by the zoning section. Unpermitted walls that fail can create liability and insurance issues. Pittsburg's sloping neighborhoods (Los Medanos Hills, Oak Hills) commonly require retaining walls.