U.S. and Mexico Sign New Colorado River Deal as Both Nations Confront a Shrinking Supply

Friday, 11 September 2026

The United States and Mexico signed a new agreement on September 2 governing how they will share Colorado River water through 2028, in what water policy experts are calling a rare bright spot of cross-border cooperation amid growing strain on the river system. The deal was finalized through the International Boundary and Water Commission (IBWC) in a signing ceremony in El Paso, Texas.

Under the new agreement, which takes effect at the start of 2027 and runs through the end of 2028, Mexico will accept a reduction of 250,000 acre-feet in its Colorado River allocation, about 17% less than its original treaty share. In exchange, Mexico gains firm, multi-year certainty about exactly how much water it can count on, replacing a previous 2017 agreement set to expire at the end of this year.

Jennifer Pitt, Colorado River programs director at the National Audubon Society, called Mexico's willingness to accept the cuts "remarkable," particularly given how much disagreement and uncertainty currently surrounds Colorado River management on the U.S. side of the border. Carlos de la Parra, managing partner of the Mexico-based Luken Center for Strategies on Water and Environment, said the deal's success reflects years of direct, in-person negotiation between U.S. and Mexican water officials at the border itself rather than remote diplomacy from Washington or Mexico City.

The binational agreement stands in sharp contrast to the situation among U.S. states sharing the river, where years of negotiation have failed to produce a voluntary agreement on how to divide mandated cutbacks. The federal government was ultimately forced to impose its own water-sharing plan, which has proven controversial and could trigger lawsuits from affected states; even without further legal challenges, that plan only provides guidance for the next two years. Snowpack in the Colorado River Basin peaked at just 58% of normal on March 18, 2026, the second-earliest and second-lowest peak on record, underscoring the physical scarcity driving these disputes.

The Colorado River once reached the Pacific Ocean at its delta in Mexico, but it has rarely done so since the 1960s due to heavy water use by cities and farms throughout the American Southwest. A coalition of conservation groups known as Raise the River has spent more than a decade using modest water allocations to restore patches of riparian habitat in the delta; a June study found the effort has helped plant more than 250,000 trees across nearly 1,400 acres. The coalition said its own water holdings, secured independently of government allocations, remain sufficient to sustain that restoration work despite the new agreement's cuts to Mexico's overall share.

Water officials on both sides described the deal as evidence that the IBWC framework, in place in some form since 1889, remains capable of producing workable agreements even as the river's overall supply continues to shrink and political tensions over its remaining water intensify.