Environmental activists and scientists from both sides of the U.S.-Mexico border met this week to coordinate a comprehensive response to the Tijuana River’s chronic pollution crisis. The talks focused on building shared monitoring systems, joint enforcement, and treating the entire 1,750-square-mile watershed as one ecological unit rather than two separate national problems. Participants committed to quarterly coordination sessions and real-time water quality data sharing, but the question now is whether those pledges translate into lasting infrastructure before the next contamination event.
Decades of Sewage Spills and Stalled Fixes
The Tijuana River begins in the Cerro El Rayo highlands east of Tecate, flows west through Tijuana’s urbanized canyons, and empties into the Pacific Ocean at Imperial Beach, California. Along the way, it collects raw and partially treated sewage, industrial runoff, and tons of sediment and trash from colonias that lack adequate drainage infrastructure. CONAGUA, Mexico’s national water commission, has estimated that Tijuana’s aging sewer system loses roughly 30% of its capacity to leaks and blockages.
On the U.S. side, the International Boundary and Water Commission (IBWC) operates the South Bay International Wastewater Treatment Plant, built in the 1990s to handle transboundary sewage. But the plant was designed to treat 25 million gallons per day and has frequently been overwhelmed during rain events that flush untreated waste across the border. Between 2019 and 2024, San Diego County issued more than 700 consecutive days of beach advisories for Imperial Beach and nearby shores.
Congress approved $300 million in 2022 through the U.S. EPA for border water infrastructure, and the IBWC broke ground in 2024 on an expansion of the South Bay plant to handle 60 million gallons per day. Yet construction timelines have slipped, and environmental groups say the expansion alone cannot solve the problem without parallel upgrades on the Mexican side of the watershed.
California Committed $46 Million for Border Pollution Projects
Earlier this year, California pledged $46 million for border pollution initiatives, funding that could support new pump stations, sediment basins, and trash capture systems in the Tijuana River Valley. The state allocation followed years of lobbying by South Bay communities and environmental organizations, including Wildcoast (Costasalvaje) and the Surfrider Foundation, both of which participated in this week’s binational meeting.
The $46 million, combined with the federal EPA funds, brings total committed U.S. spending on Tijuana River pollution to roughly $350 million since 2022. On the Mexican side, spending figures are harder to track. CONAGUA has announced multiple rehabilitation projects for Tijuana’s sewer collectors in recent years, but activists say many of those projects remain incomplete or underfunded.
This week’s meeting sought to close that coordination gap. Participants called for mapped pollution sources on both sides of the border, identification of the most critical failing infrastructure, and accountability systems designed to survive changes in local or national administrations. Mexico holds midterm elections in 2027, and Baja California will elect a new governor that same year, creating a window where political attention could shift away from environmental commitments.
Beach Closures and Health Warnings Affect Both Sides
The river’s condition determines beach safety from Imperial Beach south through Playas de Tijuana and the Rosarito corridor. On the U.S. side, the San Diego County Department of Environmental Health posts contamination advisories when bacterial counts exceed safe swimming thresholds. Those advisories have become routine rather than exceptional.
On the Mexican side, COFEPRIS, Mexico’s federal health and safety agency, monitors water quality at Baja California beaches but posts advisories less frequently and with less public visibility. Playas de Tijuana, one of the most popular beach areas for Tijuana residents and cross-border visitors, sits less than two miles south of the river mouth. During heavy rain events, plume models show contaminated water drifting south along the coast.
The health risks are not abstract. A 2023 study by San Diego State University researchers found elevated levels of antibiotic-resistant bacteria in Tijuana River sediment, raising concerns about long-term exposure for beachgoers, surfers, and residents of nearby communities. Border Patrol agents working in the Tijuana River Valley have also reported respiratory issues and skin infections linked to contaminated water and sediment.
This week’s meeting also addressed habitat restoration in the Tijuana River Estuary, a 2,500-acre reserve managed by the U.S. Fish and Wildlife Service. The estuary supports more than 370 bird species but has been degraded by repeated contamination events and invasive sediment flows that have filled channels and buried native vegetation.
The next quarterly coordination session is scheduled for October 2026, when participants plan to present a unified infrastructure priority list to officials in both countries. The binational meeting was first reported by Uniradio Baja.