Doña Ana County explores desalination, wastewater reuse and operator training to bolster water supply

Doña Ana County commissioners discussed plans on Feb. 4 to pursue desalination, wastewater recharge and workforce training as tools to shore up long-term drinking-water supplies.

The county’s assistant county manager, Steven Lopez, told the commission the county sits above substantial brackish aquifers and that tapping them with desalination and related projects could provide a local source of water “first” because those brackish zones are not covered by interstate water compacts. “This is also one of those topics that nobody else in New Mexico has talked about yet. So we would be leaders in the state,” Lopez said.

Lopez summarized options presented during a recent utilities convening hosted by the county and RCAC: desalination of deep brackish aquifers, returning treated wastewater to the aquifer through injection wells, flood-water capture and injection, and physical or regulatory linking of water systems to add redundancy. He said U.S. Geological Survey data show a brackish “sweet spot” roughly 4,000 feet down and estimated the aquifers could represent a large multi-century resource under current usage projections. He also noted contamination risks including PFAS and PFOS and said desalination and appropriate filtration would address those contaminants.

Why it matters: commissioners repeatedly framed water as a countywide priority tied to growth, public health and emergency resilience. Several commissioners urged staff to move quickly on feasibility and to involve small, local utilities so those providers do not get left behind as larger systems plan projects.

Key technical and policy points discussed - Desalination and brackish aquifers: Lopez said brackish water resources exist countywide and are not subject to existing interstate compacts, which makes local development legally attractive. He described desalination as unproven at commercial scale in New Mexico but established elsewhere in the Southwest. - Wastewater return and flood capture: Lopez described injecting treated effluent or captured stormwater back into the aquifer as a lower-cost alternative to extensive “purple pipe” reclaimed-water systems, but said these approaches require state-Engineer approval and close attention to pollutant risk. - Operator shortage and training: commissioners and staff flagged a regional shortage of certified water/wastewater operators. Lopez and several commissioners proposed internships, scholarships and a county-supported pipeline tied to Doña Ana Community College to keep trained operators local. - Regulatory barriers: staff noted statutory and regulatory constraints, including Public Regulation Commission rules that can prevent for-profit utilities from selling water to mutual domestic associations and the need for state-engineer waivers or statute changes to pursue certain flood-capture strategies.

Direct remarks and sources - Steven Lopez (Assistant County Manager): presented the convening results, described brackish aquifer data and said desalination could be a long-term county opportunity. He explained PFAS in plain terms to commissioners: “It is the stuff that makes your cooking utensils slippery… it was used in firefighting applications because it makes water more wet.” - Commissioners (Reynolds, Sanchez, Vice Chair Chaparro, Gametos and others) raised questions about phasing, cost, how to include micro-utilities and whether the county should franchise utilities or consider creating a county utility.

Board direction and next steps Commissioners gave staff direction to continue feasibility work, hold follow-up utility convenings, pursue partnerships with utilities and Doña Ana Community College, and return with legal, budget and staffing options. Lopez asked for “three heads nodding” on direction so staff could proceed with legwork and future updates. No formal vote was taken.

Ending Staff said it will refine cost estimates, identify likely pilot projects and coordinate legal review and intergovernmental outreach; commissioners asked for further briefings and a future update to the board.