Federal plant that treats wastewater from Tijuana given deadline to meet water quality standards

SAN DIEGO – The San Diego Regional Water Quality Control Board on Monday moved to compel the operators of a federal wastewater plant treating sewage flows from Tijuana to comply with a schedule for repairs and compliance. This enforcement action seeks to bring the plant into alignment with a 2021 cease-and-desist order requiring it to meet water quality standards for discharges to the Pacific Ocean.

The South Bay International Wastewater Treatment Plant, which is owned by the U.S. Section of the International Boundary and Water Commission (USIBWC), was built in 1996 to accept sewage from Tijuana via a pipe collection system and treat it to primary standards. In 2010, the plant was upgraded to include secondary treatment of effluent (liquid waste) that is discharged three miles offshore via the South Bay Ocean Outfall.

When flows began exceeding the facility’s capacity in 2020, the aging equipment failed, leaving solids and bacteria in the effluent that pose risks to marine life and human health. In response, the San Diego Water Board issued a cease-and-desist order in 2021, requiring the USIBWC to immediately address repair and maintenance issues at the treatment plant. The corrective actions included replacing and installing additional pumps, cleaning out sedimentation tanks, replacing a junction box and temporary influent pipe, and rehabilitating all mechanical parts for primary sedimentation tanks.

Despite the regional board’s 2021 directive, the plant remains out of compliance with the cease­and­desist order and exceeds effluent limitations repeatedly. The board’s action Monday escalates enforcement of the order and requires the plant to execute repairs according to a timeline and return to compliance no later than Aug. 15, 2024.

“After years of neglect, the U.S. Section of the International Boundary and Water Commission is finally making progress to repair or replace damaged or outdated equipment,” said David Gibson, executive officer of the regional board, “but several major repairs still need to be completed. This action by the board is necessary to ensure compliance with the Clean Water Act and set the stage for planned expansion to reduce transboundary flows.”

For more information about the regional board’s work on Tijuana River water quality issues, please visit the regional board website.

The San Diego Region stretches 85 miles of coastline from Laguna Beach to the U.S.- Mexico border and extends 50 miles inland to the crest of the coastal mountain range. Its growing population enjoys many water-related activities; however, the area receives little precipitation. About 90% of the water supply is imported from Northern California and the Colorado River.