Construction on the Rosarito desalination plant must begin by early August or the project risks yet another collapse. CONAGUA, Mexico’s national water commission, has scheduled the contract award for July 24, using a restricted bid process after two open tenders failed to produce a winner. If the timeline holds, the 2,200-liter-per-second facility would begin operating between 2029 and 2030.
The plant would be the second largest desalination facility in Latin America. It is designed to supply Tijuana, Rosarito and parts of Ensenada for 30 years. President Claudia Sheinbaum committed six billion pesos (roughly $300 million USD) to the project in late June 2026.
Two Open Tenders Failed Before CONAGUA Switched to Restricted Bid
CONAGUA declared both previous procurement rounds desierto, meaning no valid contract resulted. The first was a national tender in November 2025. The second was an international tender in June 2026. Neither produced a contract-ready winner, though multiple firms submitted proposals in the June round.
After the second failure, the federal government pivoted to a restricted bidding process. Under Mexican procurement law, a restricted bid (invitación a cuando menos tres personas) allows the contracting authority to skip public tender and invite a small number of prequalified firms. The process is legal but narrows the competitive field and reduces public visibility into pricing and selection criteria.
Three companies received invitations: Acciona Agua México, a subsidiary of the Spanish infrastructure giant that operates desalination plants across the Mediterranean and the Middle East; Cox Energy, which submitted the lowest economic proposal in the June round; and Tecno Arrendamientos y Construcciones, which earned the highest technical score in that same round. Acciona has been the most visible participant across both previous tenders, dropping its bid from 6.89 billion pesos to 6.32 billion pesos between rounds. It still ranked fourth in cost.
Sheinbaum hinted at a reverse auction mechanism to finalize pricing within the restricted format. In a reverse auction, bidders compete downward on price in real time, which can lower costs but also raises concerns about whether winning firms cut corners to secure the contract.
Baja’s Water System Has Struggled Through Repeated Summer Shortages
The desalination plant is not a new idea. Proposals for a large-scale reverse-osmosis facility near Rosarito have circulated since at least 2010. Multiple administrations at the state and federal level have announced timelines, allocated budgets and held groundbreaking ceremonies. None produced a working plant.
Meanwhile, the region’s water infrastructure has deteriorated. CESPT, Tijuana’s municipal water utility, delivers water through a system plagued by aging pipes, illegal connections and chronic underfunding. Summer months bring the worst stress. High demand, low reservoir levels and pipeline breaks combine to produce rolling service cuts across dozens of colonias in Tijuana and Rosarito. In 2024 and 2025, CESPT imposed rationing schedules that left some neighborhoods without service for 48 hours or more at a time.
The problem is compounded by population growth. Tijuana’s metro area, which includes Rosarito and Tecate, has grown to roughly 2.2 million residents. Thousands of foreign nationals hold property in the corridor between Rosarito and Ensenada, many in developments built without guaranteed long-term water access. The new plant’s 2,200-liter-per-second capacity is projected to serve about 2.5 million people, closing a supply gap that currently leaves the region dependent on overdrawn aquifers and water piped from the Colorado River via an aging canal system.
Three Firms Will Compete for a Contract Worth Billions
Each of the three invited firms brings a different profile. Acciona Agua México has the deepest desalination portfolio, operating facilities in Spain, Saudi Arabia and Australia. Its parent company, Acciona S.A., reported revenues of €17.8 billion in 2024. Cox Energy is a renewable energy firm with operations in Mexico and Central America. Its desalination experience is thinner, but its low-cost June bid attracted attention. Tecno Arrendamientos is a Mexican firm that scored highest on technical criteria in the June tender, suggesting strong engineering capability but less international track record.
The six-billion-peso federal commitment covers the expected construction cost, but the contract structure has not been made public. Key unknowns include who will operate the plant after construction, how water pricing will be set, and whether the 30-year supply agreement will include inflation adjustments or performance penalties.
If CONAGUA awards the contract on July 24, construction is expected to start within days. The build timeline is 36 to 48 months, placing completion between mid-2029 and mid-2030. The next public milestone is the July 24 award date. Reporting for this article drew on coverage from El Sol de Tijuana and Zeta Tijuana.