San Diego Coastkeeper Releases 2025 Tijuana River Valley Water Quality Report

SAN DIEGO, Calif. – San Diego Coastkeeper published its 2025 Tijuana River Water Quality Monitoring Report, providing a comprehensive picture of water quality conditions in the Tijuana River Valley over the past year. The findings confirm that sewage contamination, chemical pollutants, and aquatic life threshold exceedances remain chronic and widespread throughout the lower watershed and estuary. Coastkeeper collected monthly samples at two to four sites depending on flow conditions, and the data is shared with the public through an interactive data map at www.sdcoastkeeper.org/tijuana-river-map.

Key findings

• Pollution is chronic and persistent: Sewage contamination, chemical pollutants, and aquatic life threshold exceedances remain chronic and widespread throughout the lower watershed and estuary. E. coli levels at all four monitoring sites were often so high they exceeded the laboratory’s measurable range for most of the year.
• Industrial pollution: Detections of metals and industrial chemicals point to inadequate wastewater treatment at Tijuana’s manufacturing maquiladoras, with pollutants entering the sanitary sewer system or being dumped directly into surface waters.
• The case for long-term monitoring: Consistent data collection helps document persistent pollution, identify emerging concerns, evaluate changes over time, and provide the foundation for informed action.

“Our monitoring documents the unprecedented levels of sewage and industrial pollution in the Tijuana River that are causing severe impacts to public health, the Tijuana River Estuary and our coastal ocean waters,” said Phillip Musegaas, Executive Director of Coastkeeper. “Urgent action is needed at every level of government to address this crisis, and every step must be taken to compel Mexico to address the pollution from Tijuana.” 

Program Achievements

Coastkeeper uses this water quality data to drive advocacy and community engagement throughout the Tijuana River watershed. In 2025 and 2026, this work reached major milestones:

• Settled our Clean Water Act lawsuit against USIBWC following a full overhaul and 40% capacity expansion of the South Bay International Wastewater Treatment Plant, backed by nearly $800 million in federal funding
• Supported two new binational agreements, a July 2025 Memorandum of Understanding and December 2025’s Minute 333, accelerating wastewater infrastructure repairs and establishing new funding mechanisms
• Filed a USMCA petition with the Commission for Environmental Cooperation, pressing Mexico on wastewater enforcement failures
• Engaged the community through Tijuana River Action Month, Latino Conservation Week, and San Diego’s inaugural Climate Week, and continued binational data-sharing through the One Coastal Community initiative with PFEA

Future Actions & Recommendations

Coastkeeper will continue monitoring the Tijuana River through 2026, with funding sought to extend the program through 2027 and build a robust, multi-year dataset. The report calls for:

• Enforcement action against industrial polluters operating in Tijuana, on both sides of the border
• Accelerated expansion of the South Bay treatment plant no later than 2031
• Binational investment in wastewater recycling to reduce reliance on the Colorado River and desalination
• Improved trash and sediment controls to protect the estuary
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The full 2025 Tijuana River Water Quality Monitoring Report is available here.

About Coastkeeper

Founded in 1995, San Diego Coastkeeper safeguards our region’s inland and coastal waters through a strategic blend of community science, education, grassroots outreach, policy advocacy, and legal enforcement of environmental laws. This approach allows us to effectively tackle the most pressing water issues facing our region. For more information, visit sdcoastkeeper.org.