Bernalillo County, NM Fence Regulations: Retaining Walls (2026)

Section 105.1 of the Uniform Administrative Code sets the baseline: "Except as specified in subsection 110.2, no building, structure or building service equipment regulated by this Code and the Technical Codes shall be erected, constructed, enlarged, altered, repaired, moved, improved, removed, converted, or demolished unless a separate appropriate permit for each building, structure or building service equipment has first been obtained from Bernalillo County." Section 105.2 then exempts a narrow category of retaining walls: "Retaining walls that are not over three feet in height measured from the bottom of the footing to the top of the wall, unless supporting a surcharge or impounding Class IO, II or IIIA liquids."

The three-foot measurement runs from the bottom of the footing, not from finished grade, so a wall on a deep footing can trip the permit threshold well before it looks three feet tall from the yard side. The surcharge language removes the exemption regardless of height whenever the wall holds back an added load, a slope, parking surface, driveway, or structure sitting above the retained soil, rather than plain earth alone. Any wall that needs a permit falls under the plan-review process in section 105.3, and section 107.1.1 lets the certified building official "require special calculations regarding three story wood framed building, retaining walls, or any other data or computations not specifically mentioned herein in order to show correctness of the plans," meaning taller or surcharge-loaded walls commonly need a New Mexico-licensed engineer's sealed design rather than a homeowner's own drawing. Fences and freestanding masonry walls up to six feet are separately exempt under the same section 105.2, so a retaining wall and a screening fence on the same slope can face different permit rules even sitting side by side.