According to reports by Reuters and other foreign media, U.S. President Donald Trump once again accused Mexico on the 8th (local time) of violating the 1944 water-sharing treaty. He threatened to impose an additional 5% tariff on Mexico if it fails to “immediately provide more water resources” to assist American farmers.

In a social media post that day, Trump stated, “I have authorized the relevant documents—if water is not released immediately, I will impose a 5% tariff on Mexico.” He added, “The longer Mexico delays, the more our farmers suffer. Mexico has an obligation to resolve this issue immediately.”

Trump also claimed that due to violations over the past five years, Mexico “owes” the U.S. 800,000 acre-feet of water. He demanded that Mexico release 200,000 acre-feet by December 31 and provide additional water “as soon as possible” thereafter.

A spokesperson for Mexico’s Economy Ministry did not immediately respond to requests for comment.

Bloomberg noted that the dispute centers on water supply for farmers in Texas. The Trump administration is increasing pressure on Mexico to fulfill its obligations under the 1944 treaty. Last month, the U.S. State Department stated that officials from both sides had met to discuss how Mexico could take steps to “reduce water shortages and ensure compliance with the treaty.

In April this year, Donald Trump threatened to impose sanctions, including punitive tariffs, against Mexico if it failed to deliver the agreed-upon water supply to Texas under a 1944 bilateral treaty.

Mexico attributed the shortfall to climate change-induced droughts. President Claudia Sheinbaum responded to Trump’s threat on social media, stating that despite enduring three years of drought, Mexico had been mobilizing available water resources to meet its obligations to the U.S.

The U.S.-Mexico border spans over 3,000 kilometers, with 65% demarcated by international rivers. From the late 19th century to the 1950s, the two nations signed a series of treaties to address border issues, including transboundary water management—effectively burdening Mexico with a heavy “water debt.”

For example, the 1944 treaty requires Mexico to deliver one-third of the Rio Grande’s (known as the Río Bravo in Mexico) mainstream water to the U.S. every five years. By September 2020, Mexico’s compliance had exacerbated domestic water shortages in its northern states, sparking violent clashes between protesters and police.

As of July 2023, Mexico had fulfilled only about 40% of its 2020–2025 water delivery quota due to scarcity.