Mysterious, 143-Million-Gallon Sewage Spill Sparks International Investigation

Officials in the U.S. and Mexico are investigating a massive sewage spill that polluted the shores of Southern California.

The spill “from Mexico's Tijuana River that polluted miles of coastland in Southern California and northern Mexico has prompted an investigation, with U.S. officials calling it deliberate and Mexican authorities saying it was an accident caused by heavy rain,” Reuters reported.

One official said the spill “polluted 20 miles of coastland from the areas of Rosarito in Mexico to Coronado in California,” according to Reuters.

According to CNN, the problem originated in Mexico. “The spill was first spotted in early February along the beaches of San Diego, California down through Tijuana, Mexico,” the report said, citing the International Boundary and Water Commission (IBWC), a joint government entity that oversees water deals between the U.S. and Mexico.

The investigation by the IBWC is expected to wrap up by April 1, according to CNN.

"This is the worst spill we've had in over a decade," Imperial Beach Mayor Serge Dedina told FOX 5 San Diego. "More than 143 million gallons of raw sewage were discharged into the Tijuana River, which flowed through south San Diego, into Imperial Beach [causing] closed beaches from the border all the way to Coronado."

U.S. officials such as Dedina say the spill was deliberate. He said it was the result of decisions by Mexican officials to cut corners on sewer infrastructure, according to Reuters.

"It was intentional," Dedina said, per Reuters. "The big picture is we need to work to support Mexico's effort to improve the sewage infrastructure system in Tijuana so this doesn't happen again."

Mexico officials differ on that point. “A spokeswoman at the Tijuana State Public Service Commission said the spill was an accident that resulted from heavy rains collapsing a sewage interceptor in the city, adding that they notified the IBWC,” the report said.

To read more about sewage spills visit Water Online’s Source Water Contamination.