San Bernardino County, CA Fence Regulations: Retaining Walls (2026)

Retaining walls in the unincorporated area are regulated separately from ordinary fences. Per the County's Residential Development Guide, a building permit is required for "Retaining Walls over 4 ft. in height, measured from the bottom of footing or any retaining wall supporting a surcharge." Walls 4 ft or shorter without a surcharge generally do not need a building permit, but they must still respect setbacks and the Development Code. Retaining walls are not governed by the fence height table; Section 83.06.020 states the fence chapter does not apply to retaining walls, which "are regulated by Section 83.02.070 (Setback Regulations and Exceptions)." Section 83.02.070(b)(1)(B) exempts from the setback requirements "Retaining walls less than three feet in height above finished grade not to exceed four such walls within the setback" - meaning short retaining walls under 3 ft above grade may be placed in a required setback, up to a maximum of four. Taller retaining walls, walls supporting a surcharge (such as a slope or structure load above), and grading of 100 cubic yards or more may trigger grading permits and engineered calculations. The County publishes Retaining Wall Information and may require engineering for these structures. Always verify your setbacks and grading requirements with Building and Safety before construction.