La Mesa, CA Fence Regulations: Retaining Walls (2026)

Retaining walls are covered by the same subsection of La Mesa's residential development standards that regulates fences, and the code treats a fence built on top of a retaining wall as one combined structure for height purposes, measured from the midpoint between the finished grades on both sides of the wall in sections no longer than ten feet. Inside any required minimum front, rear or side yard setback, a retaining wall is capped at whatever height is needed to retain a fill of three feet on the uphill side or a cut of six feet on the downhill side; a wall retaining more than that inside the setback exceeds what the chapter allows without further approval.

Outside a required setback, the general six-foot fence-and-wall limit in Section 24.05.030(I)(1) governs instead, so where a retaining wall sits on the lot changes which numeric cap applies. A related carve-out lets corner lots that share a common rear property line with another corner lot build combination fence-and-wall structures up to six feet inside a reduced front setback, but that height still cannot exceed what Section 24.05.030(N) allows in a required sight-distance visibility triangle. Because the fill-and-cut limits are tied to the setback line rather than to a flat number, a retaining wall that steps down a slope can lawfully change height as it moves toward or away from the property boundary.