USMCA Tijuana River Watershed Public Updates
In accordance with the Memorandum of Understanding (MOU) signed by the United States and Mexico in Mexico City on July 24, 2025, U.S. Environmental Protection Agency (EPA) and Secretariat of Environment and Natural Resources (SEMARNAT) are providing the following quarterly public updates.
EPA and SEMARNAT are committed to fully and faithfully implementing the July 2025 MOU and implementing a permanent solution to the Tijuana River sewage crisis that’s afflicting communities on both sides of the U.S.-Mexico border. EPA and SEMARNAT also agree that, in accordance with the MOU, transparency and public participation are key to successfully achieving a durable solution to this crisis.
March 20, 2026 Quarterly Public Update
- On December 15, 2025, U.S. and Mexico signed a historic new agreement, called Minute 333, committing both nations to new actions, including infrastructure projects, evaluations, enhanced monitoring, and planning for operation and maintenance (O&M) of critical sites and systems that will account for future population growth in Tijuana, Mexico. The following commitments are underway:
- An interagency binational Minute 333 Work Group has been established to evaluate the following commitments:
- Review existing engineering and financial feasibility studies by the end of March 2026 on the construction of an ocean outfall at the San Antonio de los Buenos Wastewater Treatment Plant and provide a recommendation on additional studies and work that may be needed.
- Prepare a scope of work by April 2026 to conduct a comprehensive mass balance flow analysis of the Tijuana water system.
- An O&M work group has been established by EPA to develop alternative O&M strategies to fund future O&M along the border.
- An interagency binational Minute 333 Work Group has been established to evaluate the following commitments:
- With the signing of Minute 333, the U.S. met all of its obligations under the MOU for 2025. That includes:
- the completion of a 10 gallons per day (MGD) expansion of the South Bay International Wastewater Treatment Plant (SBIWTP) in 100 days;
- a 100-day review of all Minute 328 projects to ensure completion at the earliest possible date; and
- issuing the first-ever quarterly public update on MOU implementation progress.
- Mexico has begun construction of the effluent relocation project from the Arturo Herrera and La Morita Wastewater Treatment Plants. This is a phased project, with Phase 1 having an anticipated completion in mid 2027 and costing $16M. Phase 2 is anticipated for completion in December 2027. Once completed, this will prevent 10 MGD of effluent from being discharged to the Tijuana River.
- Mexico continues to make progress on the rehabilitation of the Parallel Gravity Main. Mexico secured $8.9M for this project and construction began in November 2025 with estimated completion in July 2026.
- Since Mexico has met the requirements in the MOU to begin the Effluent Relocation and Parallel Gravity Main and is exceeding their 2026 funding commitment, EPA is releasing U.S. Mexico Border Water Infrastructure Program (BWIP) funds to begin the Tijuana River Gates and PB-1 projects. These projects will prevent 5 MGD of transboundary sewage from entering the Tijuana River, and BWIP funds will ensure the PB-1 project remains on track. Immediately beginning construction also maximizes the 9-month timeline reduction secured following the July 2025 MOU signing.
- Mexico has obligated $59M in state and federal funding to begin the following projects in 2026, surpassing the $46M funding commitment for 2026 as agreed to in the MOU.
- Insurgentes Collector rehabilitation
- Two pump stations: PB-Matadero and Laureles PB-2
- Poniente Interceptor rehabilitation
- Oriente Interceptor rehabilitation
- Carranza rehabilitation
- Diversion of 10 mgd of treated effluent to the Rodriguez Dam
- Rehabilitation of the Parallel Gravity line
EPA and SEMARNAT look forward to providing further quarterly public updates in furtherance of the July 2025 MOU. Interested members of the public may submit comments or questions to EPA or SEMARNAT using the contacts listed below:
November 21, 2025 Quarterly Public Update
Accomplishments
- U.S. Section, International Boundary and Water Commission (USIBWC) completed 10 million gallons per day (mgd) interim expansion of the South Bay International Wastewater Treatment Plant (SBIWTP) on August 28, 2025. The facility is now fully operational and capable of handling 35 mgd of wastewater.
- On October 30, 2025, a list of projects to be further expedited was released, a product of a US-Mexico binational working group. This was done in accordance with Section 5 of the MOU. EPA and its partners were able to compress project timelines by 9 additional months for two key Mexico-side projects, including Tijuana River Gates and Rehabilitation of PB1 A and B.
- In total, the MOU has memorialized time savings of approximately seven (7) years for projects in Mexico and over five (5) years for projects in the United States.
- Mexico expects to secure funding for the following projects, which will begin construction in 2026:
- Insurgentes Collector
- PB-Matadero and Laureles PB-2
- Poniente Interceptor
- Oriente Interceptor
- Carranza Collector
- Backup power supply for PB1.
- In September 2025, Mexico initiated the construction of the First Phase of the Tijuana River Gates, a collection pipes project, with Mexican state and federal funds.
- Mexico is initiating the process for the construction of the following priority projects:
- Diversion of 10 mgd of treated effluent entering the Tijuana River from the Arturo Herrera and La Morita wastewater treatment plants to a site upstream of the Rodriguez Dam.
- Rehabilitation of the Parallel Gravity Line.
- U.S. and Mexico IBWC Commissioners met August 15; September 24; October 1, 7, 16, 22, 23, and 30; and November 10 and 14. International cooperation is key to fully and faithfully implementing the MOU.
- USIBWC completed a nanobubble ozonation pilot project for the Tijuana River. Preliminary results showed promise at reducing odors and bacteria. Results of the data analysis will be forthcoming.
- USIBWC started planning to accelerate the expansion of SBIWTP to 50 mgd. This is currently in the planning phase. Public updates to come.
- U.S. EPA and Mexico SEMARNAT are developing strategies for operations and maintenance (O&M) costs and accounts. EPA and SEMARNAT set up a Binational O&M workgroup (EPA, SEMARNAT, CONAGUA, NADBank and both IBWC sections) to work on this issue.
- New Treaty “Minute.” The U.S. and Mexican Sections of the IBWC are in final negotiations to undertake additional actions to address transboundary pollution at San Diego-Tijuana, leading up to signing by the end of December 2025.
EPA and SEMARNAT look forward to providing further public updates in furtherance of the July 2025 MOU. Interested members of the public may submit comments or questions to EPA or SEMARNAT using the contacts listed below: