Commerce City, CO Fence Regulations: Retaining Walls (2026)

Sec. 21-7735 of the Commerce City Land Development Code caps retaining wall height at 4 feet for any wall that is not attached to a primary structure and not needed to compensate for a change in grade on the site. A retaining wall attached to a primary structure and necessary to compensate for a grade change, with no artificial fill, can rise to 6 feet. Rather than building one tall wall, the code directs that a series of low retaining walls be used whenever possible, and where multiple walls are used, they must be spaced at least 4 feet apart horizontally.

Pedestrian safety triggers a separate rule: wherever a retaining wall creates a downward vertical drop of more than 30 inches within 4 horizontal feet of a sidewalk, walkway, or other public circulation area, a railing at least 42 inches high must run along the top edge of the wall to keep pedestrians from falling over the edge. On materials, the code favors dry-stacked native stone, precast masonry block, cast-in-place concrete, or masonry block faced with stone, brick, or stucco. Treated timber and railroad-tie walls are barred except on single-family detached and attached residential properties, and tires can never be used as a retaining wall material in any zone district.

Because a retaining wall interacts with grading and drainage, taller or structurally significant walls typically require engineering review and a building permit through Community Development before construction, and the height rules apply on top of, not instead of, the site's underlying fence standards when a fence sits on top of a retaining wall.