U.S. Conditions Aid to Mexico on Water Debt and Anti-Drug Cooperation

Washington, D.C. — The United States has conditioned aid to Mexico on the country fulfilling its water debt under a 1944 treaty and supporting joint anti-narcotics operations.

The U.S. State Department spending bill for fiscal year 2026, passed by Congress on Tuesday and signed by President Donald Trump the same day, includes a clause in the Latin America and Caribbean Assistance section that affects aid for projects in Mexico.

The law states: “None of the funds appropriated or made available by this Act may be used for assistance to the Government of Mexico until the Secretary of State [Marco Rubio] certifies and reports to the Appropriations Committees that such Government is supplying the water that Mexico owes to the United States, as established in Article 4, Section B, of the Treaty between the United States of America and Mexico relating to the utilization of the waters of the Colorado, Tijuana, and Rio Grande rivers, February 3, 1944.”

The condition does not apply, the law emphasizes, “to funds made available to counter the flow of fentanyl, fentanyl precursors, and other synthetic drugs into the United States.”

The law does not detail the allocated funds, but in fiscal year 2023, the latest with more complete data, aid to Mexico totaled $104 million.

According to the approved law, of the funds allocated for assistance to Mexico, 30% can only be committed after Rubio certifies and reports to the Appropriations Committees that, in the previous 12 months, the Mexican government took measures to:

• Reduce the amount of fentanyl reaching the U.S.-Mexico border;
• Dismantle and hold transnational criminal organizations accountable;
• Support joint anti-narcotics operations and information exchange with U.S. counterparts;
• Respect extradition requests for criminals sought by the United States; and
• Increase participation in the fight against drug trafficking at both federal and state levels.

On Tuesday, Mexico and the United States announced the definition of a technical plan to manage water deliveries by the Mexican government. Trump had threatened to impose a 5% tariff on Mexico if it did not comply with the water shipments stipulated in the 1944 treaty.

Under the plan, Mexico committed to guarantee the delivery of “an agreed minimum annual quantity between both countries, according to the hydrological conditions of the basin and the mechanisms provided in the Treaty, also prioritizing supply for human consumption and agricultural production.”

Mexico did not specify what the minimum amount of water to be delivered will be, but the U.S. government reported that Mexican authorities committed to sending a minimum of 350,000 acre-feet of water (about 430 million cubic meters) per year to the United States during the current five-year cycle, as well as a detailed plan to settle the pending water debt from the previous cycle.