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

Fountain Valley Municipal Code § 18.04.020 amends Section 105.2 of the California Building Code to list work exempt from a building permit. Item 4 covers retaining walls not over four feet (1,219 mm) in height measured from the bottom of the footing to the top of the wall, unless supporting a surcharge or impounding Class I, II or III-A liquids. The measuring point matters: height is counted from the base of the footing, not from the finished grade, so buried footing depth adds to the number.

Two conditions remove the exemption. A wall supporting a surcharge, and a wall impounding Class I, II or III-A liquids, are outside it even at four feet or less. Section 18.12.020 carries the same retaining wall exemption in the residential code list for the City of Fountain Valley.

A wall that needs a permit can also trigger site reports. Under § 18.04.070 the Building Official can require a geologic or geotechnical report or both. A geologic report must be prepared by a Certified Engineering Geologist licensed by the State of California, and a geotechnical report must be prepared by a registered Civil Engineer versed in soils engineering. When both are required they are coordinated before submission, and a fee is collected for review of the reports and any required addendums. The reports must contain a finding on the safety of the site from geologic hazards and on the effect of the work on the stability of the site and property outside it.

For freestanding fences and block walls, § 18.04.020 separately exempts fences not over six feet high and block walls not over three feet high. Fence and wall height in yards is governed by § 21.18.070. Permit work started before the permit issues costs double the permit fees under § 18.04.030. Building code appeals go to the planning commission under § 18.02.025.