Hawthorne, CA Fence Regulations: Retaining Walls (2026)

Hawthorne Municipal Code Section 17.48.020 sets distinct rules for retaining walls depending on whether they retain fill or protect a cut. Where a retaining wall contains a fill, the height of the retaining wall built to retain that fill is not counted toward the permissible height of a wall, fence, or hedge; however, any fence built above such a retaining wall may not exceed six feet in height. Where a retaining wall protecting a cut below the natural grade is located on the line separating lots or parcels, that retaining wall may be topped by a fence, wall, or hedge of the same height that would otherwise be permitted at that location if no retaining wall existed. Fence height itself is measured as the vertical distance from the top board, rail, brick, block, or wire to the base of the fence at the ground. Because retaining walls are walls under the chapter, a building permit is required before construction; taller or load-bearing retaining walls also trigger engineering and structural review under the California Building Code (which generally requires a permit for retaining walls over 4 feet measured from the bottom of the footing, or any wall retaining a surcharge).