Why an Old Water Treaty Opens a New Front Between the United States and Mexico?
The current cycle ends on October 24, and Mexico owes 1,555.9 million cubic meters—72% of what it must deliver by that date—according to the International Boundary and Water Commission (IBWC).
A bridge with flags of Mexico and the United States can be seen at the border between El Paso, Texas, and Ciudad Juárez, Chihuahua.
Mexico’s water debt to the United States, under the rules of a mutual supply treaty signed in 1944, is opening a new point of contention in the already tense relationship between the two countries. The non-compliance, which Mexico attributes to an extraordinary drought, led the U.S. to deny a water delivery to the border city of Tijuana (northwest) last Thursday.
Meanwhile, the northeastern state of Tamaulipas warns that U.S. demands for Mexico to meet its obligations could compromise its own water supply. In recent years, Mexico has struggled to meet its quota. In 2020, attempts to pay off the debt sparked protests among farmers, resulting in one fatality.
The agreement was signed to divide the water from rivers that run along the 3,100-kilometer shared border. It obliges the U.S. to deliver 1,850 million cubic meters of water annually from the Colorado River (west), while Mexico must provide 432 million cubic meters from the Río Bravo (east), known as the Rio Grande in the U.S.
To meet its obligations, Mexico has a five-year period, extendable by another five years. The current cycle ends on October 24, and Mexico still owes 1,555.9 million cubic meters—72% of what it must deliver by that date—according to the International Boundary and Water Commission (IBWC).
The situation is “critical,” said Gonzalo Hatch Kuri, a geographer and researcher at the National Autonomous University of Mexico (UNAM). “Only extreme storms during the upcoming August and September rainy season could, by miracle, allow Mexico to comply,” he explained.
The U.S. State Department’s office for Latin America and the Caribbean announced last Thursday that it would deny Mexico’s request for water from the Colorado River for Tijuana due to “ongoing deficiencies” in Mexico’s water deliveries under the treaty.
American farmers and lawmakers complain that Mexico waits until the end of each cycle to fulfill its allocation and has fallen short in recent years.
The Colorado River’s flow has decreased due to drought and high agricultural consumption in the southwestern U.S., where nearly half of the water is used for cattle and dairy farming. In southern Texas, farmers are concerned about the future of cotton, citrus, and other crops.
The water dispute adds to existing tensions, including President Donald Trump’s decision to impose a 25% tariff on Mexican imports—a measure temporarily suspended until April 2 for goods covered under the USMCA trade agreement, which also includes Canada.
In 2024, the Mexican government explained that the Río Bravo basin has suffered from a 20-year drought, which reached extreme levels in October 2023. In addition to the “extraordinary drought,” excessive water concessions for agricultural and industrial use on the Mexican side of the basin have led to overexploitation, according to the Tamaulipas Hydraulic Resources Department during a forum last Friday.
In November, the two countries signed an agreement to prevent water shortages in the southern U.S. by ensuring a more stable and reliable supply from Mexico.
To achieve this, Mexico committed to using water from the San Juan River, which flows through the states of Nuevo León and Tamaulipas. However, the Tamaulipas government claims this move “violates” the original treaty and threatens water availability in the northern region.
Mexico’s attempts to comply with the treaty have previously led to conflicts. In 2020, farmers in the northern state of Chihuahua seized the La Boquilla dam to prevent the government from using its water to supply the U.S. The confrontation between protesters and the Mexican National Guard resulted in one fatality.
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