California could sue the IBWC over pollution coming from Mexico.

Although states suing each other over cross-boundary water pollution is nothing new, it is somewhat more novel to have a city sue an international body. This may soon be the case, as Imperial Beach, CA has threatened to sue the International Boundary and Water Commission (IBWC) over failure to address pollution coming in from the Mexican side of the Tijuana River, according to Bloomberg BNA. The IBWC, an international body made up of both United States and Mexican officials, oversees transboundary water issues between the United States and Mexico per the U.S.-Mexico Water Boundary Treaty of 1889. Last November, IBWC regulated a boundary dispute between the two nations involving an encroachment by citizens in Zapata, Texas.

Imperial Beach has alleged that the IBWC “has made ‘zero’ effort to address water pollution from daily unchecked discharges of stormwater, sewage, and trash flowing into the U.S. from Mexico.” The city claims that trucks have been illegally dumping sewage into the Tijuana River on the Mexican side of the border. The River flows across the border, where it is treated by the South Bay International Wastewater Treatment Plant in San Diego, CA, before reaching Imperial Beach and, consequently, the Pacific Ocean. Imperial Beach alleges that the South Bay Plant, which was established by the IBWC in 1999 to resolve the issue of untreated sewage flowing across the border, is unable to handle the amount of sewage being dumped, and has thus violated the United States Clean Water Act (CWA) by permitting untreated sewage to reach Imperial Beach. In response, the IBWC claims that it is already taking measures to address the city’s concerns, including proposed plant expansions and additional flow meters on both sides of the border.

If Imperial Beach’s allegations about trucks dumping sewage into the Tijuana River are true, this may invoke additional international concerns between the two countries. Water pollution in Mexico is primarily regulated by the National Waters Law (Ley de Agus Nacionales, or LAN), which in part regulates discharges into federal water bodies. If Mexico is found to not effectively be enforcing the LAN, it may be found to be in violation of the North American Agreement on Environmental Cooperation (NAAEC), sometimes referred to as the NAFTA Environmental Side Agreement. The NAAEC is a parallel agreement to NAFTA, where the United States, Canada, and Mexico have agreed to take certain steps towards protecting North America’s environment, including adequate enforcement of domestic environmental laws. Private citizens and NGOs of any NAFTA country can submit concerns online regarding any nation’s inability to meet NAAEC obligations. A failure to meet NAAEC obligations is subject to the same methods of dispute resolution as would govern other NAFTA disputes.

When sued by the Arizona Department of Environmental Quality in May of 2012 for similar international discharges that were not processed through the Nogales International Wastewater Treatment Plant in Rio Rico, IBWC responded by suing the city of Nogales, Arizona, as owners of the Plant. If Imperial Beach ends up filing suit against IBWC in the present case, the Commission may be expected to bring the city of San Diego into the case as owners of the South Bay Plant. It remains to be seen how this issue will be handled, and whether or not international dispute resolution will become a necessity to resolve it.