Transboundary flows from Mexico have historically posed challenges to water quality, public health, and the environment in the San Diego border region. Today, dedicated efforts on both sides of the border are helping to reduce pollution, improve stormwater and wastewater management, and safeguard natural ecosystems.
Progress Timeline & Announcements
• In September 2024, the United States Environmental Protection Agency (EPA) formally transferred
United States-Mexico-Canada Agreement (USMCA) funds to the U.S. International Boundary and
Water Commission for the South Bay International Wastewater Treatment Plant (SBIWTP)
Rehabilitation and Expansion Project. For more information and updates on this important project,
visit: https://www.epa.gov/sustainable-water-infrastructure/usmca-tijuana-river-watershed.
• In May 2025, the IBWC and EPA announced that the incremental expansion of SBIWTP, from existing
capacity of 25 million gallons per day (MGD) to 35 MGD, will be fast-tracked to complete in 100 days,
rather than the originally projected two years.
• In June 2025, the United States International Boundary and Water Commission (USIBWC) announced
that they are exploring further acceleration toward full expansion (50 MGD).
For the most up-to-date information and FAQs regarding the current progress on Tijuana River pollution, please visit the City of Imperial Beach’s official website here.
