Mexico, United States Reach Agreement on Water Deliveries

Amid renewed political tension and unprecedented hydrological stress, Mexico and the United States have reached a bilateral understanding to strengthen water management in the Rio Grande basin under the 1944 Water Treaty. The Government of Mexico has reiterated that it has not violated the treaty and that all actions taken remain fully aligned with its provisions, water availability, and infrastructure constraints.

The agreement comes after weeks of intensive technical negotiations aimed at improving management of the current five-year cycle and addressing the deficit carried over from the previous cycle, as explicitly allowed under Art. 4 of the treaty in cases of extraordinary drought.

Extraordinary Drought and Treaty Flexibility

Last week, President Claudia Sheinbaum along with other Mexican authorities emphasized that the Rio Grande basin has experienced an extraordinary and unprecedented drought affecting users on both sides of the border. Under these conditions, Mexico has made additional water deliveries whenever hydrological conditions permitted, states Sheinbaum, while prioritizing drinking water supply for border communities and safeguarding domestic agricultural production.

Officials argue that treaty compliance must be assessed over the full five-year cycle, not through short-term political deadlines. As of Oct. 24, 2025, the final accounting date of the current cycle, Mexico had delivered 1,091 million m³ (884,861 acre-feet), equivalent to 50.6% of the required volume, according to the US section of the International Boundary and Water Commission (IBWC). Mexico maintains that this outcome reflects historic drought conditions rather than noncompliance.

Under the joint understanding, Mexico intends to release 249.2 million m³ (202,000 acre-feet) of water to the United States, with deliveries expected to begin the week of Dec. 15, 2025. Both governments confirmed that negotiations are ongoing to finalize a broader plan by Jan. 31, 2026, covering both current obligations and the repayment of the previous cycle’s deficit.

The two countries reaffirmed their commitment to continued cooperation within the institutional framework of the IBWC/CILA, while acknowledging that each retains sovereign rights to act in accordance with national interests and international treaty obligations in the event of noncompliance.

US Political Pressure and Tariff Threats

Last week, US President Donald Trump accused Mexico of violating the treaty and threatened to impose a 5% tariff on Mexican imports if additional water was not released immediately. In a Dec. 9 post on Truth Social, Trump claimed Mexico owed more than 800,000 acre-feet of water and demanded that 200,000 acre-feet be delivered before Dec. 31, framing the issue as an emergency for Texas farmers and ranchers.

Trump also linked treaty compliance to broader environmental concerns, sharing a video alleging untreated sewage flows from Tijuana into the Tijuana River, although Mexican officials argue this issue is unrelated to Rio Grande treaty accounting and stems from local infrastructure failures.

US Secretary of Agriculture Brooke Rollins welcomes the agreement, stating that it would provide greater certainty to South Texas producers. She warns that the United States reserves the right to impose tariffs if Mexico fails to meet its commitments.

Mexico’s Response: Hydrology, Infrastructure, and Human Rights

Mexican officials have strongly rejected accusations of treaty violation. Roberto Velasco, Deputy Minister for North America at the Ministry of Foreign Affairs, stresses that the treaty explicitly allows drought-related shortfalls to be repaid in subsequent cycles.

President Claudia Sheinbaum underscores that compliance is constrained not only by rainfall but also by physical infrastructure and constitutional obligations. As of December 2025, La Amistad Reservoir holds about 153 million m³, less than 9% of Mexico’s usable storage, while Falcon Dam holds about 51 million m³, under 4% of Mexico’s share. These volumes are largely reserved to guarantee drinking water for 13 Mexican border cities.

Sheinbaum also highlights operational limits, noting that infrastructure such as El Granero Dam has a maximum release capacity of around 20m³/s, making sudden large-scale releases physically impossible regardless of political pressure.

“We will comply with the treaty, but always respecting the human right to water and ensuring that Mexican communities and agriculture are not put at risk,” Sheinbaum states.