Environmental Rules in Doña Ana County, NM (2026)
4 rules for unincorporated Doña Ana County, New Mexico.
Verified from official government sources
Stormwater Management
Doña Ana County's grading and drainage rules, § 350-605G, require developed sites to hold post-development stormwater runoff to no more than pre-development levels and size drainage structures for the 100-year storm, with detention ponds built to 125% of that volume. The permit follows from the county's MS4 discharge permit under the federal Clean Water Act's NPDES program.
Doña Ana County Stormwater Drainage Design Standards
Some RestrictionsCode of Doña Ana County § 350-605G(17), (19)(a)
Total surface runoff from the proposed improved site into existing or future developments shall not exceed the runoff from the area of land prior to development. The engineer may utilize retention/detention ponds, swales, drainage channels, pumping facilities or any other approved methods to restrict runoff to accomplish this task. ... Construction plans and details for drainage structures shal...
Erosion Control
Any grading, construction, demolition or development that needs a county permit must have an approved erosion control plan (ECP) in place first, under § 350-605D of the Doña Ana County Code. Grading is capped to the building pad, pond, driveway and five extra feet around them unless the applicant justifies more, and the plan can be folded into construction drawings.
Doña Ana County Erosion Control Plan Rule
Some RestrictionsCode of Doña Ana County § 350-605D, D(1)
Erosion control plan (ECP). Any grading, construction, demolition, or development requiring a permit or other form of approval under any County ordinance shall have an approved ECP in place prior to receiving a permit. The ECP may be separate documents, or incorporated as part of required construction plans. ... New development. Any development that requires a permit under any County ordinance ...
Flood Zones
Doña Ana County adopts FEMA's Flood Insurance Study and rate maps by reference, and any development inside a mapped special flood hazard area needs a floodplain development permit before work begins. New residential construction must sit at least one foot above the base flood elevation, verified by a licensed surveyor.
Doña Ana County Floodplain Development Rules
Some RestrictionsDoña Ana County Code § 350-604A, C, H(1)
A. Basis for establishing area of special flood hazard. The areas of special flood hazard identified by the effective Federal Emergency Management Agency in a scientific and engineering report entitled "The Flood Insurance Study for Doña Ana County, New Mexico," with accompanying Flood Insurance Rate Maps and Flood Boundary-Floodway Maps (FIRM and FBFM), and any revisions thereto are hereby ado...
Flood Elevation Requirements
Doña Ana County requires new and substantially improved structures in FEMA-mapped special flood hazard areas to elevate the lowest floor one foot above the base flood elevation. A floodplain development permit and elevation certificates, prepared and sealed by a New Mexico-registered surveyor, are required before, during and after construction. The rule applies only in the unincorporated county.
Doña Ana County Flood Elevation Freeboard Rule
Some RestrictionsCode of Doña Ana County § 350-604H(1)
New construction substantial improvement, or reconstruction due to substantial damage of any insurable structure, in addition to all equipment or mechanical items servicing the structure shall have the lowest floor (including basement) elevated to one foot above the base flood elevation. A registered professional land surveyor shall submit an elevation certification to the Floodplain Administra...
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