After decades of pollution and finger-pointing, both countries are teaming up to reclaim a coastline in crisis.
For decades, raw sewage has flowed across the U.S.-Mexico border into the Tijuana River and onto the beaches of San Diego. The toxic brew has closed shorelines, sickened swimmers, and turned what should be paradise into a public health disaster.
But now, a landmark binational agreement offers a glimmer of hope. Backed by over half a billion dollars from both governments and coordinated by the International Boundary and Water Commission, the deal focuses on fixing treatment plants, repairing failing infrastructure, and expanding capacity on both sides of the border.
For communities in San Diego and Tijuana, this isn’t just a win for water quality—it’s a long-overdue act of justice. If implemented fully and transparently, the agreement could mark a turning point in one of North America’s longest-running environmental crises.
1. The Tijuana River has dumped sewage into San Diego for decades
The Tijuana River flows north from Mexico into California, and when it rains, it carries untreated sewage, chemicals, and trash straight onto U.S. beaches. This issue has plagued the region for over 30 years. Storm drains in Tijuana overflow easily, and with limited wastewater treatment capacity, much of the waste goes straight into the river.
On the U.S. side, Imperial Beach is usually the first to suffer. During heavy rainfall, the contamination becomes so severe that the beach is often closed to the public for weeks or even months. Residents have reported illness, respiratory problems, and economic losses from the tourism downturn.
Locals and activists have long called for a fix. Now, with federal funding and cross-border collaboration finally aligned, there’s a shot at ending this toxic cycle.
2. U.S. beaches have closed hundreds of times because of this pollution
According to San Diego County officials, beach closures from cross-border sewage have skyrocketed in recent years. In 2023 alone, over 700 beach closure days were logged—some stretches closed for more than 200 consecutive days. Imperial Beach, Coronado, and Silver Strand have all been impacted.
The contamination isn’t just gross—it’s dangerous. High levels of bacteria like E. coli and enterococcus have made the water unsafe for swimmers and surfers, prompting lifeguards to raise black flags almost constantly.
Families and local businesses have suffered as public trust in the water quality has plummeted. For a coastal region that relies on clean beaches for both recreation and revenue, the economic and emotional toll of constant closures can’t be overstated.
3. A $474 million agreement was signed to tackle the crisis
In a rare show of binational cooperation, the U.S. and Mexico signed a $474 million agreement in 2023 to overhaul the aging sewage systems on both sides of the border. The plan is spearheaded by the International Boundary and Water Commission (IBWC) and includes funding from the U.S. Environmental Protection Agency, Mexico’s National Water Commission (CONAGUA), and other state and local partners.
The goal is to expand sewage treatment capacity, repair broken infrastructure, and reduce the amount of untreated waste flowing north. The deal includes firm targets and timelines, and both nations are being held accountable for hitting those marks. While implementation will take years, it’s the most ambitious and well-funded solution ever proposed for this problem—and environmental advocates are cautiously optimistic.
4. The expansion of the South Bay International Wastewater Plant is key
A central part of the agreement is a major expansion of the South Bay International Wastewater Treatment Plant (SBIWTP) in San Ysidro. The plant is operated by the U.S. section of the IBWC and treats wastewater from Tijuana. However, it has long been over capacity and under-resourced. Under the new deal, the plant will nearly double its treatment capacity—from 25 million gallons per day to 50 million. This will help prevent sewage from bypassing the system entirely during heavy rains.
The upgrades include advanced filtration, odor control, and infrastructure to handle future growth. For decades, the plant has been a political football. Now, with real money on the table, it could finally become a reliable bulwark against pollution.
5. Tijuana will also get its own wastewater upgrades
Mexico isn’t off the hook in this agreement. A portion of the funding will go toward fixing broken sewer lines and treatment plants in Tijuana. Many of the city’s pipes are cracked, corroded, or simply overwhelmed by population growth and inadequate planning. The deal includes money to repair the San Antonio de los Buenos plant—one of the worst polluters—and to build more modern pump stations to direct sewage into proper treatment facilities.
Mexico’s government has also committed to long-term maintenance, not just temporary fixes. If both countries follow through, the result will be fewer emergency discharges and a healthier binational watershed.
6. Surfers and environmental activists helped bring the issue to light
While politicians and bureaucrats debated, it was local surfers, residents, and environmental groups who sounded the alarm. Organizations like Wildcoast, Surfrider Foundation, and Clean Border Water Now have led protests, filed lawsuits, and organized water quality testing for years. Surfers falling ill after riding waves near the border shared their stories, drawing media attention and public outrage. Grassroots pressure ultimately pushed lawmakers in both countries to act.
The new agreement is, in part, a testament to that persistence. It shows that citizen action can eventually break through political inertia—especially when public health and natural ecosystems are at stake.
7. The U.S. Navy has also been impacted by the pollution
This isn’t just a surfer or tourist issue—military readiness has also taken a hit. U.S. Navy SEALs train along the beaches of Coronado and Imperial Beach, and several exercises have been canceled or relocated due to bacterial contamination from sewage spills. Navy officials have expressed frustration that their elite forces are being exposed to health risks while trying to train in domestic waters.
The Department of Defense has even joined advocacy efforts to support funding for clean water infrastructure. When one of the world’s most advanced naval forces can’t safely use American beaches, it’s a clear sign that the problem has national security implications as well as environmental ones.
8. Public health threats from the sewage are growing
Doctors and researchers have documented increasing cases of gastrointestinal illness, skin infections, and respiratory problems in communities near the polluted coastline. A 2022 San Diego State University study linked cross-border pollution to spikes in emergency room visits and hospitalizations, particularly during rainy seasons. Children, the elderly, and those with preexisting conditions are most at risk.
The contamination includes more than just human waste—it can contain industrial chemicals, heavy metals, and pharmaceutical residues. Every day that untreated sewage flows onto U.S. soil is another day people are being exposed to substances that could impact their long-term health. It’s more than an inconvenience—it’s a public health crisis.
9. The plan includes new monitoring and accountability measures
A key part of the new agreement is transparency. Both nations have agreed to step up water testing, publish pollution data regularly, and involve the public in oversight. Sensors and sampling stations will be installed along the Tijuana River, coastal estuaries, and affected beaches to track progress in real time. Independent watchdog groups will also be invited to monitor the results.
This kind of visibility is a major shift from the secrecy and finger-pointing of past decades. It ensures that if pollution continues, there will be no hiding behind vague promises. For the public, this means real-time alerts and more trust in the system.
10. Delays, politics, or underfunding could still derail the deal
As promising as the new agreement is, it’s not immune to the same roadblocks that have plagued past efforts. Construction delays, permitting backlogs, or shifts in political leadership could slow implementation. Critics worry that without continued pressure from the public and consistent funding, the project could lose momentum. Congress must continue appropriating funds, and local officials need to make sure work stays on schedule.
If this becomes another half-built solution, it will only deepen public cynicism. That said, the project has more bipartisan support than ever before—so there’s real hope that it will survive the hurdles ahead.
11. A cleaner future could boost tourism and the local economy
San Diego’s southern beaches could see a massive tourism resurgence if pollution is controlled. Right now, families avoid the area because of health warnings. Hotels lose bookings, restaurants struggle, and the regional economy takes a hit. Fixing the sewage crisis won’t just clean the water—it could revitalize an entire coastline.
Surfing competitions, beach festivals, and eco-tourism could return to Imperial Beach and neighboring areas. With improved public trust and fewer closures, local businesses would thrive. The cost of inaction has been counted in sick days and shuttered doors. The benefits of fixing the problem go far beyond public health—they ripple through the economy.
12. If it works, this could become a model for international cooperation
What’s happening between Mexico and the U.S. on the Tijuana River could be a global example of how to address shared environmental crises. Border regions around the world face similar challenges—rivers that don’t care about jurisdiction, pollution that crosses invisible lines. If this agreement succeeds, it may inspire similar frameworks in places like India and Bangladesh, or between countries sharing the Nile or Mekong rivers.
Climate change and population growth will only make cross-border pollution worse in the years ahead. The Tijuana deal shows that with political will, public pressure, and solid science, nations can find common cause—even in a toxic mess.