San Diego County, CA Fence Regulations: Retaining Walls (2026)

Retaining walls in unincorporated San Diego County are regulated by the Building Division under the California Building Code (CBC) as amended and adopted by the County. Per handout PDS-084 (Retaining Walls With Level Backfill, rev. 01/01/2023), construction of a retaining wall requires a permit except for walls less than 3 feet in height that do not support a surcharge. A surcharge is any added load behind the wall - a building foundation, driveway, parking, slope, or other loading. Wall height is measured from the top of the footing to the top of the wall. No building foundation, driveway, parking, or other loading on the upper level is allowed within a horizontal distance equal to the height of the wall; walls carrying such loads (or walls not matching the prescriptive designs in the handout) must be designed by a California-licensed architect, civil engineer, or structural engineer. The companion handout PDS-083 covers retaining walls with sloping backfill. PDS-084 specifies prescriptive standards: footings extending at least 12 inches into undisturbed natural soil or compacted fill at 90% density (based on a 1,000 psf bearing value), 4-inch wall drains at 6-foot intervals with 12-inch gravel backfill, type 'N' fully grouted block, and inspection holds at footing, pre-grout, post-grout, and completion stages. Larger grading-related walls associated with Department of Public Works grading use County Regional Standards.