18.212.220: RETAINING WALLS REQUIRED WHEN:
   A.   Retaining walls shall not exceed six feet (6') in height, except in front yard areas where retaining walls may not exceed thirty inches (30") in height. However, retaining walls necessary for the construction of an adjacent driveway may be constructed to a maximum of six feet (6') in height at any location on the property.
   B.   Retaining walls exceeding thirty inches (30") in height will require a protective fence or guardrail of at least thirty six inches (36") in height either of solid material or with intermediate members so spaced that a nine inch (9") sphere will not pass through. The combination of a retaining wall may not exceed nine feet (9'), except if such retaining wall and guardrail is within fifteen feet (15') of an existing dwelling, the combination of retaining walls and guardrails shall not exceed six feet (6') in height. (Prior code § 86305)