Water Treaty Puts Mexico Under U.S. Delivery Pressure

Mexico says it met the minimum Rio Grande water volume owed to the United States for the first year of a new five-year cycle, under a treaty backed by Washington’s tariff threat. The full delivery tally remains unpublished, as does the amount applied to Mexico’s earlier water debt.

A treaty measured in water and tariffs

The 1944 Water Treaty divides Rio Grande and Colorado River water, with the International Boundary and Water Commission (IBWC) administering the agreement and settling disputes. Under its terms, the United States receives one-third of the flow reaching the Rio Grande from six named Mexican tributaries. That share “shall not be less, as an average amount in cycles of five consecutive years, than 350,000 acre-feet annually,” in the commission’s wording.

Across five years, Mexico’s Rio Grande obligation totals 1.75 million acre-feet, or about 2.16 billion cubic meters. Mexico is guaranteed 1.5 million acre-feet a year from the Colorado River. Those cross-border allocations run through a joint commission, while the people living with drought and water restrictions have no accounting power described in the agreement.

On December 12, 2025, the US Department of Agriculture announced that Mexico would release 202,000 acre-feet and repay the previous cycle’s deficit. US Agriculture Secretary Brooke Rollins warned that “if Mexico continues to violate its commitments,” the United States would impose 5% tariffs on Mexican goods. The water arrangement came with an economic penalty attached.

The shortfall, and the missing numbers

The IBWC’s last posted tally for the previous cycle, which ended October 24, 2025, showed an estimated 884,861 acre-feet delivered against a 1,750,000-acre-foot target. The remaining balance hasn’t been reported. The account of the new cycle offers no full year-one total, no precise figure for debt repayment, and no clarity on whether the commission’s records match the figures reported by both governments.

El Economista reported on April 6 that 413 million cubic meters had been delivered between January and March, citing Mexico’s section of the commission. It said the amount exceeded the monthly pace needed for the five-year total, while some of the December release was meant to address both the earlier shortfall and the current cycle. What portion went to each obligation remains unclear.

Drought gives these obligations a human cost. Mexico’s Foreign Ministry said the country met the minimum volume despite extreme drought and without putting at risk the human right to water, community consumption or food production, particularly along the border. An April report citing Mexico’s national water commission said Chihuahua, Coahuila, Nuevo León and Tamaulipas faced the worst drought. El Economista reported in July, citing a researcher at El Colegio de la Frontera Norte, that Mexico’s Colorado River supply was cut by 182 million cubic meters, or 10%, in 2026.

Officials claim cooperation; the pressure remains

A February 3, 2026, statement by Secretary of State Marco Rubio and Rollins said Mexico had committed to deliver at least 350,000 acre-feet annually and to a detailed plan to repay all outstanding debt. Monthly meetings would follow a call the previous week between Presidents Donald Trump and Claudia Sheinbaum. No announcement said whether Washington would consider the year-one result sufficient to end its tariff warning.

In July, Sheinbaum said the treaty wasn’t part of USMCA negotiations, known in Mexico as the T-MEC. She called claims that Mexico was missing its quota “false” and said, “we are complying perfectly.” Mexico’s ambassador in Washington, Roberto Lazzeri, wrote that the result “shows what our two countries can achieve when they work together.”

Rollins said pending deliveries “remain critical” for South Texas farmers and ranchers who rely on the water “to sustain their operations and feed our nation.” She credited President Trump’s leadership and coordination with Sheinbaum for reaching the target, and said, “The work is not finished.” The sources don’t say what she meant by pending deliveries, or whether rainfall will let Mexico maintain its pace. Cycle 37 runs from October 2025 to October 2030, leaving four yearly accounting periods after the first.