Mexico and U.S. Sign Agreement to Address Border Sanitation in Tijuana, Baja California–San Diego, California

• This agreement advances comprehensive border sanitation efforts in the Tijuana-San Diego region. These measures will significantly reduce discharges of untreated wastewater and sediments into the Tijuana River and the Pacific Ocean, benefiting the environment and the health of the border population.

On December 15, 2025, through Minute 333 of the International Boundary and Water Commission (IBWC), titled "Comprehensive Actions to Address the Border Sanitation Problem at Tijuana, Baja California - San Diego, California," both governments established a clear path for binational collaboration to comprehensively, structurally, and sustainably address this historic problem. The Minute was signed in the city of Tijuana and received approval from both governments, entering into force immediately.

This agreement sets out a series of technical, financial, and governance measures to carry out specific sanitation projects in Tijuana, including new treatment and sediment control infrastructure that will have a positive impact on public health, the environment, and the beaches of Tijuana and San Diego. It also establishes long-term water planning for the area through a master plan and comprehensive technical studies that will anticipate urban growth and prevent future crises.

Notably, the United States will assume financial co-responsibility through the North American Development Bank (NADB) to ensure the operation and maintenance of the infrastructure on the Mexican side and prevent its deterioration over time. This new arrangement confirms that the solution to border sanitation is not one country's obligation alone but a shared responsibility.

This agreement gives continuity to the Memorandum of Understanding signed on July 24, 2025, in Mexico City between Mexico's Secretary of Environment and Natural Resources, Alicia Bárcena Ibarra, and the Administrator of the U.S. Environmental Protection Agency, Lee Zeldin, reinforcing the technical and institutional cooperation between both countries.

Mexico reaffirms its commitment to work with the United States in a spirit of cooperation and mutual respect to advance lasting solutions that contribute to the wellbeing of the border communities and deepen the bilateral relationship.