Aliso Viejo, CA Fence Regulations: Retaining Walls (2026)

Aliso Viejo Municipal Code § 15.14.030 defines the words fence and wall as interchangeable for any fence, freestanding wall, retaining wall, screen or windscreen, so retaining walls sit inside the same section as ordinary fences. Subsection H is the retaining wall rule. Walls up to six feet in height are permitted, with one condition: if the wall is over 30 inches high and visible from off-site locations, it has to be landscaped with shrubs or vines served by automatic irrigation. A low wall of 30 inches or less is not subject to that planting condition.

Subsection H(2) deals with safety railings. Open railings up to 48 inches high placed on top of a retaining or other wall and required for pedestrian safety are allowed only if an increase in height is approved per subsection (J).

Subsection J is the path for anything beyond the printed maximums. Fences higher than the maximums set out in the section, up to a maximum of 10 feet, can be approved by the director as an exception permit under AVMC 15.74.070. Applications for fences exceeding 10 feet in height go to the city council as a site development permit under AVMC 15.74.020 and need a public hearing. Because subsection A counts a retaining wall as a type of fence, a retaining wall proposal over the printed maximum follows that route.

Height measurement also matters on sloping City of Aliso Viejo lots. Height runs from finish grade at the base to the highest point on the interior or exterior side, whichever is higher, and where an adjoining site is higher than the base within a side or rear setback, measurement can start from that site but cannot exceed eight feet from the lower side. The section prints no engineering or stamped plan requirement for retaining walls.