Cross-border agreement aims to combat ocean pollution through addressing San Diego's sewage crisis
The United States and Mexico signed a Memorandum of Understanding (MOU) on July 24, 2025, aiming to provide a long-term solution to the cross-border flow of untreated sewage from Tijuana into San Diego, California. This agreement, a significant step towards binational progress, follows high-profile discussions and visits between U.S. and Mexican officials, who have emphasized the urgency and importance of the issue[1][3][5].
The MOU lays out a comprehensive, accelerated binational plan focused on expanding wastewater treatment capacity, completing infrastructure upgrades by 2027, securing necessary funding, and ending the environmental hazard of raw sewage flowing from Tijuana into Southern California permanently[1][3][5].
Key details and progress of the MOU include:
- Infrastructure Expansion: The U.S. International Boundary and Water Commission (IBWC) committed to completing the expansion of the South Bay International Wastewater Treatment Plant (SBIWTP) to increase its capacity from 25 million gallons per day (MGD) to 35 MGD by August 28, 2025, on an accelerated 100-day construction schedule[1][5]. The San Antonio de los Buenos plant in Mexico will have its capacity doubled by Mexico[4].
- Completion Timeline: The agreement sets a fast-tracked schedule to finish all related infrastructure projects under the previously established Minute 328 of the U.S.-Mexico Water Treaty by December 31, 2027. It also includes provisions to handle future sewage growth and system maintenance[5].
- Financial Commitments: Mexico pledged to allocate the remaining $93 million of funds from Minute 328 to implement these projects, fulfilling financial obligations crucial to the plan[3].
- Environmental and Health Impact: The MOU aims to stop billions of gallons of untreated sewage and toxic chemicals crossing the border, which have caused beach closures, pollution of the Pacific Ocean, health issues, and economic damage on both sides of the border for decades[1][3].
- Political and Binational Cooperation: The signing was led by EPA Administrator Lee Zeldin and Mexico’s Secretary of the Environment Alicia Bárcena Ibarra, highlighting a strong cooperative commitment to the issue[1][3][5].
However, the agreement does not directly address the river and its pollution, potentially causing further complications. Local proponents, such as Supervisor Paloma Aguirre, have called for a more straightforward agreement regarding the river and its pollution[6]. Since 2018, over 100 billion gallons of trash and industrial chemical-laden sewage have contaminated San Diego's seas[7].
In addition, California is distributing air purifiers due to airborne contaminants from evaporated sewage foam[2]. The contamination has caused beach closures for more than 1,000 days in a row and health problems for Border Patrol agents, Navy SEALs, and locals[1].
Mexican President Claudia Sheinbaum has hailed the agreement as a sign of binational progress, bringing hope to Imperial Beach and other affected communities[1]. The MOU will be finalized with a new Minute by December 2025[1].
References: [1] The New York Times. (2025). U.S. and Mexico Sign Agreement to End Tijuana River Sewage Crisis. Retrieved from https://www.nytimes.com/2025/07/24/us/us-mexico-tijuana-sewage-crisis.html [2] ABC News. (2025). California Distributing Air Purifiers Due to Sewage Foam Contamination. Retrieved from https://abcnews.go.com/US/california-distributing-air-purifiers-sewage-foam-contamination/story?id=83645667 [3] The Washington Post. (2025). Mexico to Spend $93 Million to Improve Tijuana's Sewage System. Retrieved from https://www.washingtonpost.com/world/the_americas/mexico-to-spend-93-million-to-improve-tijuanas-sewage-system/2025/07/24/341e186e-62f3-11ed-960a-91d0d4909d8b_story.html [4] Associated Press. (2025). Mexico to Double Capacity of San Antonio de los Buenos Wastewater Plant. Retrieved from https://apnews.com/article/mexico-wastewater-tijuana-san-antonio-de-los-buenos-pollution-3a50068a903e91731a685136b67c523c [5] The Los Angeles Times. (2025). U.S.-Mexico Sign Agreement to End Tijuana River Sewage Crisis. Retrieved from https://www.latimes.com/california/story/2025-07-24/us-mexico-sign-agreement-to-end-tijuana-river-sewage-crisis [6] San Diego Union-Tribune. (2025). Local Leaders Call for More Direct Action on Tijuana River Pollution. Retrieved from https://www.sandiegouniontribune.com/news/environment/story/2025-07-26/local-leaders-call-for-more-direct-action-on-tijuana-river-pollution [7] KPBS. (2025). Over 100 Billion Gallons of Trash and Sewage Contaminate San Diego's Seas Since 2018. Retrieved from https://www.kpbs.org/news/2025/07/29/over-100-billion-gallons-of-trash-and-sewage-contaminate-san-diegos-seas-since-2018
- The signed Memorandum of Understanding (MOU) between the United States and Mexico focuses on environmental issues, specifically addressing the environmental hazard of untreated sewage flowing from Tijuana into Southern California.
- In addition to the agreement, local advocates are calling for a more direct policy-and-legislation-oriented approach to address the pollution of the Tijuana River.
- The MOU includes provisions for environmental science, committing to expanding wastewater treatment capacity and securing funding for the projects, which will have a significant impact on reducing climate-change-related issues like beach closures and pollution of the Pacific Ocean.
- To further address environmental concerns, environmental NGOs and the general news media are closely monitoring the reporting of the progress of the MOU and its potential impact on policy-and-legislation regarding the environmental issue.
- The MOU's signing represents a significant step in binational cooperation and politics, with key figures like EPA Administrator Lee Zeldin and Mexico’s Secretary of the Environment Alicia Bárcena Ibarra emphasizing the importance of environmental issues.
