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

Otero County's Subdivision of Land regulations, Chapter 200, require every preliminary plat to come with a draft disclosure statement, and the chapter's purpose language directs the county to assure the adequacy of drainage facilities before land is divided. The operative drainage rule sits in § 200-12.C(4): the disclosure statement's attachments must include a terrain management plan covering soils types, conditions and surface flow data, and that plan must affirmatively provide that runoff generated by improvements on the lots is contained on the lots and that the subdivision produces no increase in discharge once improvements are built.

The same subsection requires an evaluation of subsurface drainage adequacy tied to septic systems, since most unincorporated lots rely on individual wells and septic rather than county sewer. Section 200-12.A(15) separately requires the preliminary plat itself to show existing drainage channels, water and erosion control structures, and surface water flow paths, including any diversion ditch, dam, or earth berm already in place on or off the subdivision, and § 200-12.C(5) requires a vicinity map showing every drainage channel and watercourse within three miles so reviewers can judge the upstream drainage area.

The Planning Coordinator reviews this material for completeness within 30 days of application under § 200-13, and an incomplete submission gives the subdivider 60 days to fix the deficiencies. For land within a mapped Special Flood Hazard Area, Otero County's separate Flood Damage Prevention chapter adds a further check: § 135-20.E requires a full drainage study for any subdivision or development covering more than 50 lots or five acres, and floodwaters from that land cannot be allowed to drain off faster or in greater volume than existed before development.