What is the water agreement that Trump is accusing Mexico of violating (and for which he is threatening to impose tariffs on Mexican products)?

Farmer with a mask that says: "The water comes from Chihuahua" — caption, A farmer in Chihuahua, northern Mexico, during protests in 2020 against the withdrawal of water in times of drought to comply with the treaty with the United States.

- Author, Drafting
- Author title, BBC News World
April 11, 2025

Updated December 9, 2025

The dispute over the implementation of a treaty signed in 1944 regulating the distribution of the waters of the Bravo and Colorado rivers between the United States and Mexico is heating up again.

President Donald Trump announced Monday that he had given the green light to documentation to impose a 5% tariff on products from Mexico if the neighboring country “continues to violate the treaty.”

In a message published on his network Truth Social, the president emphasized that Mexico owes the United States more than 986 million cubic meters of water and set December 31 as the deadline for Mexico to deliver more than 246 million cubic meters of water.

“The longer it takes for Mexico to release the water, the greater the damage will be to our farmers,” Trump warned, calling on Claudia Sheinbaum’s government to “solve” the problem now.

Implementation of the treaty has in the past sparked strong protests from Mexican farmers who say the withdrawal of water is unacceptable to the United States. In times of drought, it seriously threatens their livelihood.

Trump had already threatened Mexico with tariffs and even sanctions over the water issue in April.

“Mexico is failing to meet its commitment. This… is seriously harming farmers in South Texas,” Trump wrote on his Truth Social platform at the time.

“Last month I stopped water shipments to Tijuana until Mexico complied with the 1944 water treaty… and “We will continue to escalate the consequences, including tariffs and perhaps even sanctions, until Mexico complies with the treaty and gives Texas the water it deserves,” he added.

The President of Mexico, Claudia Sheinbaum, responded to Trump at the time with a message on her official X account.

“Yesterday a comprehensive proposal was sent to the undersecretary of state of the US State Department to regulate the delivery of water to Texas under the 1944 treaty, which provides for very short-term measures. There have been three years of drought and Mexico has complied with it in terms of water availability.”

“I have directed the Secretaries of Agriculture, Rural Development and Foreign Affairs and the Secretary of Environment and Natural Resources to immediately contact the Secretary of Agriculture and the Department of State of the United States Government. I am sure that, as on other issues, an agreement will be reached,” the president said in April.

Clashes between farmers with sticks and the National Guard in Chihuahua — caption, In 2020, farmers in Chihuahua confronted the National Guard when the government announced it would withdraw water from the Boquilla Dam to send to the United States.

What is in the contract?

In a sense, one could say that it is the so-called Treaty on the Distribution of International Waters The agreement signed by Mexico and the United States in 1944 predates another agreement concluded almost a century before that date.

The Treaty of Peace, Friendship, Boundaries and Final Settlement (better known as the Treaty of Guadalupe Hidalgo), signed in 1848 at the end of the war sparked by the Texas Dispute between the two countries, stipulated that Mexico would at that point cede more than half of its territory to the United States.

In addition, it also formed the border between the two countries on the Rio Grande – called the Rio Grande by the Americans – and whose waters have always been the center of the conflict in Chihuahua.

The strategic location of the river required a distribution plan between both actors. After years of negotiations and several failed proposals, Mexico and the United States signed the treaty in force today in Washington.

Map with explanations of the 1944 water treaty — caption,

According to the agreement, Mexico retains two-thirds of the Bravo’s main flow and leaves the rest to its neighbor, which cannot be less than about 432 million cubic meters (Mm3) per year.

In return, the USA gives Mexico 1,850 million m3 of the Colorado River every year, which runs mostly on US soil but also crosses the border between the two countries until it flows into the Gulf of California between the Mexican states of Baja California and Sonora.

The agreement also specifies that the International Boundary and Water Commission (IBWC), a binational body, will be responsible for resolving possible differences over boundaries.

Representatives of Mexico and the USA sign the treaty in Washington in 1944 — caption, Representatives of Mexico and the United States signed the treaty in Washington in 1944.

The pact stipulates that the US will meet its water deliveries every year, while Mexico will be able to do so in five-year periods.

“It is one of the best agreements reached in history regarding the United States,” former President Andrés Manuel López Obrador said in 2020.

Should the Treaty be reformed?

Reforming or updating the terms of a treaty signed 76 years ago could be one of the ways to resolve conflicts.

However, some analysts believe that both the agreed liters of water and the ability to deliver some of it every five years instead of annually are advantages that Mexico should not lose.

Aerial view showing low water level in Boquilla Dam — caption, In this April 2025 image you can see low water levels in the Boquilla Dam in Chihuahua due to drought.

For farmers on the Mexican side of the border, something much more immediate is at stake than the diplomatic back-and-forth between the two countries in times of drought made worse by climate change.

The 2020 clashes between farmers and the National Guard in Chihuahua came after the government decided to withdraw water from the Boquilla Dam to comply with its contract with the United States.

At that time, farmers’ spokesman Salvador Alcantar, president of the Association of Irrigation Users of Chihuahua (Aurech), pointed out that the future of about 20,000 families living in the region’s countryside was at risk.

Alcantar shared one of his biggest fears with BBC Mundo:

“In 1995, the dams were not opened for planting and there was a massive exodus from our communities. Men of productive age left the country to support the family; it was a severe family breakdown that we are still suffering from,” he recalls.

“And that’s the social problem we could see again if we don’t plant next year.”