Broomfield, CO Fence Regulations: Retaining Walls (2026)

Section 15-03-070(B), B.M.C. lists work exempt from the building permit requirement, and item 1 under the 'Building' category exempts 'retaining walls that are three feet (1,219 mm) or less in height measured from the bottom of the footing to the top of the wall, unless supporting a surcharge or impounding flammable liquids.' That measurement runs from the footing, not from finished grade, so a wall with a deeper footing counts taller than it looks above ground. The surcharge carve-out means even a short wall needs a permit if it bears extra load, such as a driveway, patio, or structure built above it.

Any retaining wall over three feet, or a shorter wall with a surcharge or flammable-liquid load, requires an application to the building official under section 15-03-070(A), review of construction documents and, where the building official requires it, an engineered design (15-03-080). The permit is reviewed and issued by the Division of Building Safety and Inspection Services (15-03-050), and lapses if work is not started within 180 days or is suspended that long (15-03-070(E)). Site grading around a retaining wall is regulated separately: Broomfield's local Appendix J112 amendment requires 'all grading' to secure a permit from the City and County Engineering Department (J112.3.1), on top of any building permit for the wall itself.