Cross-border environmental cooperation reaches a pivotal moment as the United States and Mexico formalize their commitment to ending decades of sewage contamination affecting both nations. The signing of Minute 333 represents a breakthrough in diplomatic negotiations that have historically stalled over funding disputes and infrastructure responsibilities. This landmark agreement promises to transform the polluted Tijuana River Valley while protecting public health across the San Diego-Tijuana metropolitan region.
Historic Minute 333 accelerates binational sewage solutions
The International Boundary and Water Commission signed Minute 333 on Monday. It defines a holistic strategy that will solve the sewage problem in the Tijuana River. This development came after the signing of the Memorandum of Understanding in July 2025 in Mexico City by Environmental Protection Agency Administrator Lee Zeldin and Mexican Environment Minister Alicia Bárcena Ibarra.
The agreement outlines the type of projects associated with infrastructure and the ability to monitor and maintain them, taking into consideration the growing population of the developing area of the Tijuana border region. The significance of the agreement has not escaped the notice of EPA Administrator Lee Zeldin, who made mention of the infrastructure projects on the Mexican side of the border.
Minute 333 has been agreed and signed in a record time of five months, while there are some Minute agreements that have taken years to arrive at, thus highlighting the efforts of the Trump administration in using effective mechanisms in order to address transboundary environmental issues competently and efficiently by both countries.
Large-scale projects target sources of pollution
The agreement calls for several key infrastructure enhancements on the Mexican side of the border, including doubling the treatment capacity and adding an ocean outfall at the wastewater treatment facility in southwestern Tijuana. Mexico will also construct a sediment basin in the vicinity of the Matadero Canyon to hold the polluted runoff that currently crosses the border to California.
According to the agreement, Mexico has the mandate to develop a master plan aimed at providing water resources to cater to the projected population increment. This should be done within a period not exceeding six months. Some additional projects comprise the construction of the Tecolote-La Gloria Wastewater Treatment Plant, which would have a capacity to treat 3 million gallons per day as of December 2028.
Key agreement components:
- Doubled treatment plant capacity with ocean outfall
- Sediment basin construction in Matadero Canyon
- Master infrastructure plan within 6 months
- New 3 MGD treatment plant by December 2028
- Operations and maintenance funding account
Financial Structure ensures sustainable long-term operation
Minute 333 encourages innovative funding arrangements, which helps U.S. taxpayers because it ensures the sustainability of the programs through the guarantees of the Mexican government and development banks. Minute 333 establishes the operations and maintenance account at the North American Development Bank and provides initial levels of funds to undertake the operations and maintenance of the facilities.
Notably, this agreement will not require any further public funds from U.S. taxpayers, including those on the Mexican side, while offering a cost-sharing formula in working to clean up and dredge sediment within the Tijuana River Basin. Of note, this agreement has remedied problems in the former agreements by ensuring mandatory maintenance to offer a lasting environmental impact to both countries.
“A lot of progress has been made this year towards achieving the 100% solution to the problem in the Tijuana River sewage issue, but none of it would matter if we didn’t take action to address natural growth in the Tijuana area,” EPA Administrator Lee Zeldin explained, referring to Minute 333.
This historic accord represents a paradigm shift with regard to addressing transboundary environmental matters by pursuing creative diplomacy and infrastructure approaches. It was clearly necessary to address the health and economic issues faced by the border regions within the time frames and through funding that was sustainable and included within the accord.
