A California senator has introduced a resolution urging the United States to freeze renewal of the USMCA trade agreement until Mexico makes binding commitments to stop sewage flowing into the Tijuana River. Senate Joint Resolution 13, filed in late March by Democratic Sen. Steve Padilla of San Diego, targets the treaty’s 2026 review window as leverage to force environmental action on a crisis that has plagued both sides of the border for decades.
The resolution is non-binding, meaning it cannot compel the White House or Congress to act. But it marks the most explicit attempt yet to link the Tijuana River pollution crisis to the enormous trade relationship governed by the USMCA, the successor to NAFTA that took effect in 2020.
Tijuana River Pollution Ranked Second Worst in the US in 2025
The Tijuana River was named the second most contaminated river in the United States in 2025. The contamination is not new. Chronic sewage spills have triggered prolonged beach closures along the San Diego County coastline, affecting communities from Imperial Beach to Coronado. In early May 2026, a sewage plume from Tijuana reached Coronado beaches, prompting public health warnings and renewed fury from residents on both sides of the border.
The root cause is an infrastructure deficit that stretches back three decades. When NAFTA took effect in 1994, it spurred rapid industrial growth in northern Mexico. Tijuana’s maquiladora sector boomed, and the city’s population surged past two million. But wastewater infrastructure never kept pace. CESPT, Tijuana’s municipal water and sewer utility, operates aging treatment plants that routinely fail during heavy rains or mechanical breakdowns. When they fail, raw or partially treated sewage flows into the Tijuana River channel and, eventually, into the Pacific Ocean.
On the US side, the International Boundary and Water Commission (IBWC) operates the South Bay International Wastewater Treatment Plant in San Ysidro. That facility, built in the 1990s, was designed to handle 25 million gallons per day of diverted Mexican sewage. Congress approved $300 million through the USMCA Implementation Act in 2020 for upgrades and expansion, and additional federal funds have trickled in since. Yet construction timelines have stretched, and the volume of cross-border flows regularly overwhelms existing capacity. During major spill events, tens of millions of gallons of untreated wastewater have crossed the border in a single day.
USMCA Article 34.7 Requires a Joint Review in 2026
Padilla’s resolution zeroes in on a specific provision of the trade agreement. Article 34.7 of the USMCA requires the three signatory nations, the US, Mexico, and Canada, to conduct a formal joint review six years after the treaty’s entry into force. That review, due in 2026, determines whether the parties agree to extend the agreement for an additional 16 years. Without extension, the treaty expires on July 1, 2036.
The resolution calls on the US government to suspend extension discussions until Mexico provides “binding and measurable commitments” to eliminate wastewater discharges into the Tijuana River basin. It also covers the New River, which carries industrial and agricultural pollution from Mexicali into California’s Imperial Valley. Padilla framed the issue in stark terms: “Trade agreements must not ignore environmental harm or the real threat that increased economic activity poses to our border communities.”
The USMCA is the framework governing roughly $1.6 trillion in annual trade among the three countries. Mexico is the United States’ largest trading partner, and Baja California’s economy depends heavily on cross-border manufacturing and commerce. Tijuana alone hosts more than 900 maquiladoras employing over 200,000 workers, many producing goods destined for the US market.
Beach Closures and Water Advisories Affect Both Sides of the Border
The practical consequences of the pollution crisis are felt daily along the coast. In San Diego County, Imperial Beach has endured more than 1,000 consecutive days of beach closures or water-contact advisories at various points in recent years. On the Mexican side, Playas de Tijuana regularly posts contamination warnings, and swimmers are advised against entering the water near the river mouth.
Property values in affected coastal areas have taken a hit. Small businesses that depend on beach tourism, from surf shops to seafood stands, have reported steep revenue declines during extended closure periods. The health effects are also documented: residents in the Tijuana River Valley on the US side have reported respiratory issues linked to hydrogen sulfide gas emanating from contaminated flows.
Padilla’s resolution faces long odds in the current US Senate, where trade policy is largely controlled by the White House under fast-track authority. Still, it adds political pressure at a moment when the USMCA review is already complicated by disputes over auto manufacturing rules, labor enforcement, and energy policy. The joint review process is expected to unfold throughout 2026. This story was first reported by Punto Norte.