Arizona's Water Infrastructure Finance Authority board approved about $14.2 million in study funds for two Mexico-based water projects on 5 October 2026, according to reporting published on 7 October 2026: roughly $8.5 million for a second Gulf of California seawater desalination feasibility study and about $5.7 million for a separate water-reuse and purification study that could include treatment for Tijuana, Mexicali and San Luis Rio Colorado (azcentral.com and The Arizona Republic). Both projects are pitched as Arizona helping produce water for Mexico in exchange for a share of Mexico's Colorado River allocation.
Key takeaways
- Arizona's Water Infrastructure Finance Authority board approved the study funds at a special meeting on 5 October 2026 (azcentral.com and The Arizona Republic).
- The desalination study alone is budgeted at nearly $8.5 million, and a separate water-reuse study received about $5.7 million (azcentral.com and The Arizona Republic).
- Both Mexico projects are proposed by the Acciona-Fengate Water Augmentation Alliance, the same international coalition that has pitched California and Baja California options to the board (azcentral.com and The Arizona Republic).
- The desalination plant could be sited near Puerto Peñasco or Playa Arenosa, could take at least 12 years to develop, and is sized at up to 500,000 acre-feet a year; the reuse project could be delivered in less than half that time at around 50,000 acre-feet a year (azcentral.com and The Arizona Republic).
- Mexico is preparing to scale reuse, with 143.8 cubic metres per second of wastewater processed by municipal plants in 2024 and roughly 40% delivered through purple-pipe networks (Mexico Business News).
What was approved and what it means for Arizona supplies
The board action was framed as a way to import water to offset Colorado River shortages that are already being felt this year and could deepen. "This is not about finding one silver bullet project," authority Executive Director Chelsea McGuire said, describing the search for regional tools rather than a single asset (azcentral.com and The Arizona Republic). Board member Ted Cooke added that communicating why cross-border projects are a win-win is part of the authority's remit (azcentral.com and The Arizona Republic).
Both Mexico projects would funnel capital south of the border in return for a portion of Mexico's Colorado River water, with the desalination plan also leaving open an option to pipe water north (azcentral.com and The Arizona Republic). The board separately has roughly $12 million in earlier approvals for two California projects and, in August, directed $7 million toward studies EPCOR is running for two California schemes that the Canadian utility says could yield 200,000 acre-feet for Arizona, one of which would clean Tijuana River sewage for reuse (azcentral.com and The Arizona Republic).
Arizona is bracing for cuts of at least 760,000 acre-feet a year from its 2.8 million-acre-foot Colorado River allocation, a level the report ties to the pending federal acceptance of a 1.25 million acre-feet-a-year collective reduction by Arizona, California and Nevada (azcentral.com and The Arizona Republic). The new Mexico studies will look at capital cost, buyer demand, and whether affected residents, local governments, tribes and other stakeholders in Mexico and California will accept the projects (azcentral.com and The Arizona Republic).
Why this matters for cross-border reuse
The Mexico study is being read against a national reuse market that is already sizeable but uneven. Mexico Business News reported that municipal treatment plants processed 143.8 cubic metres per second of wastewater in 2024, of which roughly 40% was delivered directly through purple-pipe networks and about 53% counted as indirect reuse (Mexico Business News). The outlet quoted a CONAGUA 2025 reference and noted that the National Association of Water and Sanitation Utilities (ANEAS) treats the headline 93% total reuse figure as inflated by indirect reuse that is not the product of deliberate planning, agreed water-quality requirements or contracts (Mexico Business News).
Reported benchmark projects already in operation frame the engineering choices: SAPAL in León is planning to convey up to 400 litres per second of reclaimed water to El Palote Reservoir through 26 km of purple-pipe infrastructure that aggregates the Municipal, Las Joyas and El Avelín treatment plants, and the Atotonilco plant in the Mezquital Valley is described as one of the country's largest agricultural reuse systems (Mexico Business News). A Sept. 24-25 forum convened by CONAGUA, the Consejo Consultivo del Agua, CERSHI and several UNAM departments concluded that a single reuse rule for Mexico would need to use differentiated, risk-based criteria for parks, industrial supply, food production and aquifer recharge, and that treatment, demand and institutional capacity have to be designed as one system (Mexico Business News).
Specification read
The reported 500,000 acre-feet/year target for the Gulf of California desalination plant works out to roughly 1.65 million m³/day, and the 50,000 acre-feet/year reuse study works out to roughly 165,000 m³/day; an acre-foot of about 326,000 gallons is enough to support roughly three households for a year, per the figures the reporting cited (azcentral.com and The Arizona Republic). For an asset of this class the reference treatment train is intake screening, pretreatment, seawater reverse osmosis with energy recovery, and brine discharge management for the desalination side, and for the reuse study the relevant train is screening, primary clarification, biological treatment (A2O, MBR, MBBR, SBR or UASB depending on influent), tertiary filtration, and disinfection, with polishing and concentrate handling if indirect potable or industrial reuse is in scope. The event itself does not yet fix a flow, influent BOD/COD envelope, or discharge standard, so any unit-capacity or feed-strength reading here is the buyer's own input rather than a reported value.
For an operator or municipal utility evaluating a cross-border reuse or desalination scheme, the signal is that Arizona is now funding the feasibility work that will set baseline cost, throughput, and acceptance parameters for a project class sized in the hundreds of thousands of m³/day range. If your plant is in the same band — flows in the tens of thousands to low hundreds of thousands of m³/day, BOD/COD in the typical 200-500 mg/L municipal envelope, with a discharge or reuse limit that ties into a national reuse framework — this is the kind of large-scale reference project you will be benchmarked against. The 2026-2030 National Water Program is promoting treated water in landscaping, industry and agriculture under circular-economy principles, and the next step the Mexico forum flagged is a national reuse policy with technical, institutional and financial certainty (Mexico Business News).
Procurement leads tracking reference designs for very large reuse trains can line up the engineering options on MBR membrane systems and the broader water purification equipment class, and engineers scoping new-build or upgrade projects can use the 2026 modular wastewater treatment buyer's guide alongside the 2026 PFAS treatment technology evaluation buyer's guide.
FAQ
How much has Arizona committed to the Mexico water studies so far? The board approved about $8.5 million for a second Gulf of California desalination feasibility study and about $5.7 million for a separate water-reuse study at a 5 October 2026 special meeting, on top of roughly $12 million earlier for two California projects (azcentral.com and The Arizona Republic).
Who is behind the Mexico desalination and reuse proposals? Both projects are proposed by the international coalition Acciona-Fengate Water Augmentation Alliance, which has also pitched Pacific Coast desalination and Southern California farm-fallowing options that the board asked staff to refine before a possible later vote (azcentral.com and The Arizona Republic).
What size of plant is the study pointing to? The reporting cites up to 500,000 acre-feet a year (roughly 1.65 million m³/day) for the desalination option near Puerto Peñasco or Playa Arenosa, and about 50,000 acre-feet a year (roughly 165,000 m³/day) for the reuse study, with a development horizon of at least 12 years for desalination and under half that for reuse (azcentral.com and The Arizona Republic). A specific influent load, footprint or capex number for either scheme was not reported.
What is Mexico's policy direction on reuse if these projects advance? Mexico's 2026-2030 National Water Program promotes treated water in landscaping, industry and agriculture, and a Sept. 24-25 forum concluded the country now needs a national reuse policy with risk-based criteria, assigned institutional responsibility, and financial certainty, including tariffs that reflect life-cycle cost (Mexico Business News).
