Moreno Valley, CA Fence Regulations: Retaining Walls (2026)

Moreno Valley has rolling terrain in areas near the Box Springs Mountains and along the Reche Canyon corridor where retaining walls are common. The California Building Code, adopted locally under Moreno Valley Municipal Code Title 8, requires a building permit for any retaining wall more than 4 feet tall measured from the bottom of the footing to the top of the wall. Any wall supporting a surcharge — meaning additional weight from a structure, driveway, parking area, or steep slope above — requires a permit regardless of height. Plans must be prepared by a California-licensed civil or structural engineer when the wall exceeds 4 feet, and soils reports may be required in expansive soil areas. Walls must be engineered to retain both soil pressure and any surcharge loads, and proper drainage — typically weep holes or a perforated drain behind the wall — is required to prevent hydrostatic pressure. Retaining walls are generally allowed up to property lines but cannot redirect surface water onto neighboring properties per Civil Code principles. Coordination with adjacent property owners is strongly encouraged when walls are on or near a shared boundary. Combination retaining-plus-fence walls where the fence portion exceeds 6 feet total may require additional permitting.