More than 143 million gallons of raw sewage - slowly leaking into the Tijuana River - has made its way to the coast, stinking up parts of Imperial Beach.
According to a report by the International Boundary and Water Commission, the leak started February 6. The sewage, which came from Mexico, slowly began seeping into the river.
All over Imperial Beach, signs warn residents: "Don't go in the water."
“This by far was the worst sewage spill in over a decade, if not ever,” said Imperial Beach Mayor Serge Dedina.
Mayor Dedina says the city filed an official complaint on February 15.
“It stunk up an area probably about 15 miles along the river, so you had residents along the river complaining about it," he said. "And then it contaminated a stretch of coastline for more than 20 miles in the US and Mexico."
The IBWC says the leak was likely caused by sewer construction gone wrong.
Dedina is asking for a federal investigation into what happened.
“This shouldn't have happened," Dedina said. "It was absolutely unacceptable that it happened and number two, it was unacceptable that we weren't notified.”
The next step will be a community meeting on the issue, which will take place March 2, 2017.