WASHINGTON, Texas - U.S. Senator John Cornyn is linking Mexico’s water debt to the United States with the current review of USMCA.
Cornyn has sent a letter to the United States Trade Representative, Ambassador Jamieson Greer, urging him to bring up the ongoing 1944 Water Treaty issue during the United States-Mexico-Canada Agreement (USMCA) joint review.
Texas’ senior senator believes this will put more pressure on Mexico to comply with its annual water deliveries to the United States.
"Mexico has repeatedly refused to meet its obligations under the 1944 Water Treaty, even when having a sufficient supply. To make matters worse, Mexican agriculture, particularly in the Chihuahua area, which uses water from the Treaty Tributaries, has seen significant expansion," Cornyn wrote.
Here is the letter:
January 28, 2026
Ambassador Jameson Greer
United States Trade Representative
Office of the United States Trade Representative
600 17th Street NW
Washington DC, 20508
Dear Ambassador Greer,
I write to express my concern regarding Mexico's decades-long failure to meet its obligations under the 1944 Water Treaty relating to the “utilization of waters of the Colorado and Tijuana Rivers and of the Rio Grande.”
As you and the Trump Administration review the United States-Mexico-Canada Agreement (USMCA), I ask you to consider raising the 1944 Water Treaty during the 2026 USMCA review.
As you know, the 1944 Water Treaty requires Mexico to deliver 350,000 acre-feet of water annually to the United States in five-year cycles. However, during the past five-year cycle, Mexico continually failed to deliver its obligated water to the United States, hurting many South Texas agriculture producers.
I'm grateful President Trump has prioritized this issue and for the actions taken last year by U.S. Department of State Secretary Marco Rubio and U.S. Department of Agriculture Secretary Brooke Rollins. It was onl.y because of President Trump's leadership that Mexico began making water deliveries in 2025.
As of October 25, 2025, Mexico delivered 884,863 acre-feet out of the required 1.7 5 million acre-feet required for a five-year cycle. Under President Trump's leadership, Mexico delivered more water over the last year than in the four previous years combined under the Biden Administration. Under President Trump's leadership, now is the time to continue to ensure Mexico complies with their water delivery obligations.
Texas, specifically the Rio Grande Valley, which encompasses more than 500,000 acres of irrigated farmland and over one million residents, is significantly impacted by Mexico's failure to deliver water. The region's farmers, including those producing fresh fruits and vegetables, have faced years of reduced production due to Mexico's lack of compliance. As a result, in 2024 Texas' only sugar mill closed after 51 years due to insufficient water to sustain cane crops, resulting in the loss of 500 jobs in Texas.
Mexico has repeatedly refused to meet its obligations under the 1944 Water Treaty, even when having a sufficient supply. To make matters worse, Mexican agriculture, particularly in the Chihuahua area, which uses water from the Treaty Tributaries, has seen significant expansion.
Mexican farmers are growing competing crops, using water that should have been shared between the United States and Mexico. In 2022, Mexico has around 3 million acre-feet in its Treaty Tributaries, and still refused to deliver water to the United States. If Mexico had delivered its obligated water to the United States in 2022 and 2023, the Rio Grande Valley Sugar Mill would likely still be in operation today.
Consequently, Mexico's ongoing non-compliance with the 1944 Water Treaty has resulted in significant economic harm and substantial losses for the agricultural industry in South Texas. Without action, additional agriculture operations and related industries across the South Texas region will remain at risk.
Therefore, I respectfully request that you consider raising Mexico's lack of compliance with the 1944 Water Treaty during the USMA review process and consider any possible mechanisms to ensure Mexico complies with the obligated annual water deliveries to the United States.
I appreciate your leadership on the USMCA and trade relations with Mexico, and I look forward to working with you and President Trump as you examine the 1944 Water Treaty and its possible inclusion in the USMCA review. Thank you for your consideration of this request. I look forward to your reply.
Sincerely,
John Cornyn
United States Senator
Ambassador, Jamieson Greer, U.S. Trade Representative. (Photo credit: U.S. Sen. Marsha Blackburn)
The Trade Representative's Office issued this statement on Jan. 28, 2026:
Ambassador Greer met today with Mexican Secretary of Economy Marcelo Ebrard to discuss bilateral trade relations and the upcoming USMCA Joint Review. Both sides recognized substantial progress in recent months and agreed to continue intensive engagement to address non-tariff barriers. In addition, they agreed to begin formal discussions on possible structural and strategic reforms in the context of the first USMCA Joint Review, including stronger rules of origin for key industrial goods, enhanced collaboration on critical minerals, and increased external trade policy alignment to defend workers and producers in the United States and Mexico and to combat the relentless dumping of manufactured goods in our region.
