Doña Ana County, NM Fence Regulations: Retaining Walls (2026)

Doña Ana County adopted Appendix DD, the New Urbanism District Regulations, in April 2024 by Ordinance No. 351-2024, to carry out the Santa Teresa Master Development Concept first approved under Resolution No. 08-010. The appendix, codified at § 350-830, applies only to land zoned into the county's New Urbanism transect and mixed-use districts (STR-1, STR-2, MU-NC, MU-MSC, and MU-CC), not to the rest of the unincorporated county's standard residential and commercial zones. 7E governs fences and walls together, and its retaining-wall rules sit inside the location standards.

Retaining walls built after a lot's original development may not cross the property boundary: no part of the wall or its footing may extend onto a neighboring parcel. Once a retaining wall holds back more than 30 inches of soil or other fill material, or once any wall in the district exceeds 72 inches in height, the design must come from a professional engineer licensed to practice in New Mexico, the same engineering threshold the section applies to tall screening fences generally. 7E(1) requires a zoning permit from the Zoning Administrator, valid for 180 days, which is itself a prerequisite for the building permit the county then issues.

Outside the New Urbanism district, the county's general grading ordinance in Chapter 350, Article VI, separately requires retaining walls built as part of a grading permit to be handled by a licensed engineer and caps fill-slope retaining walls at 15 feet.