Regional leaders representing both the United States and Mexico will gather in Imperial Beach, California Friday for a rare discussion between the two countries about a flow of sewage crossing the border in the South Bay region of San Diego.

Elected leaders and non-government representatives from both countries hope the meeting at the Dempsey Holder Safety Center Friday afternoon will begin a dialogue as to how to solve the sewage seepage.

San Diego-area residents have complained for years that their health and wellbeing is being affected by pollution to the Tijuana River Estuary. Polluted runoff likely comes from a Tijuana sewage treatment plant in need of upgrades that would likely cost upwards of $370 million, a study by Mexican officials found.

The Tijuana River Estuary and shorelines from Imperial Beach to Coronado are often closed to the public after spills on the Mexican side of the border cross into the United States via the Tijuana River, especially following heavy rainfall.

The meeting aims to go over what work has been done so far to address the problem and provide an overview of current plans, as well as addressing what hurdles remain.

The long-standing problem has become a source of contention between leaders on both sides of the border as to who is responsible for a solution. The issue reached the courts last year when Attorney General Xavier Becerra sued the International Boundary Water Commission.

The suit alleges millions of gallons of waste, including untreated sewage, trash, pesticides and heavy metals have been discharged from the IBWC's treatment facilities in violation of the Clean Water Act. The San Diego Regional Water Quality Board and the city of San Diego have also joined the suit.

It asks the court to force the IBWC to comply with the Clean Water Act and the National Pollution Discharge Elimination System (NPDES) permit. But the IBWC argued in a motion to dismiss the lawsuit that the agency is not responsible for the millions of gallons of raw and partially treated sewage that flow into the Pacific Ocean from the Tijuana area.

The last time a sewage spill caused long-lasting beach closures in San Diego County was in December 2018. That's when officials with Mexico's IBWC told the U.S. that an estimated 6 to 7 gallons of sewage per day was flowing into the Tijuana River Valley due to a failure at their plant.

The Tijuana River crosses the U.S.-Mexico border just west of the Otay Mesa Port of Entry and travels northwest, through the Tijuana River Estuary and into the Pacific Ocean south of Imperial Beach.