Fremont, CA Fence Regulations: Retaining Walls (2026)

Under Fremont Municipal Code Section 18.171.020(d), where the height of a retaining wall within a required yard prevents a property owner from also erecting a fence at least four feet tall, the code allows an open fence up to four feet to go up in that same yard despite the retaining wall already occupying part of the vertical space. This is a narrow height accommodation, not a blanket exemption: the retaining wall and any fence on top of it are still measured together for overall height purposes elsewhere in the fence chapter.

Where a retaining wall is built as part of a grading project inside a designated slope control area, Fremont Municipal Code Section 18.205.330(f) imposes engineering standards beyond the fence chapter. Retaining walls are to be avoided where possible, particularly at the toes of high slopes, and if installed they must be constructed of concrete or other masonry (or approved timber capped at three feet), engineered to carry all earth pressure including embankment surcharge. The code further limits height: a retaining wall cannot exceed one-half of the horizontal distance from the dwelling's foundation wall to the face of the wall, and side yard walls are capped at four feet, unless no required window faces the wall. Section 18.205.330(g) separately requires fencing along the top of slopes over 15 feet or walls over four feet, if the city engineer determines it is needed for safety.