Valencia County, NM Environmental Rules: Stormwater Management (2026)

013 (Engineering Design Criteria) under Chapter 94: Streets and Roads, set the drainage requirements that apply whenever a road, street, or subdivision is built or improved in the unincorporated county. Subsection (D) requires a standard 6-inch high barrier-type curb and gutter with a 1-inch gutter depth as the exterior curb section for every class of road or street required to have curb and gutter, built to the county's Standard Details; a shallower mountable curb may be used on local roads only if both traffic and drainage needs are satisfied to the Public Works Director's approval.

Concrete curb and gutter must be Class A, 4,000-psi Portland cement concrete, with expansion joints every 24 feet and construction joints at least every 8 feet. Where a road is built without curb and gutter, every driveway crossing it must instead be provided with a culvert at least 12 inches in diameter, or larger if drainage-flow calculations for a 10-year, 24-hour storm event require it, at every driveway that accesses a public or county road. The culvert has to be set for positive downhill drainage and placed in the graded swale that actually carries the runoff, not just anywhere convenient.

Any developer or property owner wanting to deviate from these curb, gutter, or culvert standards needs the Public Works Director's written approval first; there is no self-certification path. 014, requires permits and easements for any drainage work tied to a subdivision, and requires all construction to follow the New Mexico Standard Specifications for Public Works Construction as modified by the county's own Standard Details, with the county's Subdivision Regulations controlling first if the two conflict.