In 2022 the International Boundary and Water Commission, a joint commission of the United States and Mexico, and the U.S. Environmental Protection Agency announced they had awarded a $4.65-million contract to Arcadis, the first contract in an effort to double the size and capacity of the U.S. section of the IBWC’s South Bay International Wastewater Treatment Plant in San Diego.

Since then local lawmakers have asked for even more federal funding for a system that's been consistently overwhelmed by sewage flows, with components breaking down from rainfall events like Tropical Storm Hillary and generally from a previous lack of maintenance. Imperial Beach in San Diego County has had swimming advisories for over 500 days due to due to raw sewage being pumped from three sources around Tijuana and San Diego into the Pacific Ocean.

Earlier this month, Rep. Scott Peters (D-Calif.) and several other members of California's congressional delegation sent a letter to the U.S. State Department demanding a full accounting of how the South Bay International Wastewater Treatment Plant fell into such a severe state of disrepair.

In their letter, the representatives said, "It remains unclear how the plant fell behind on maintenance since it was previously expanded in 2002." They asked who is responsible for the plant's maintenance, when did the USIBWC become aware of its deteriorated condition and whether or not a contractor is partially responsible for the plant’s deterioration.

Peters writes, "the State Department highlighted the deferred fundamental repairs and excess wastewater flows from Mexico beyond the plant’s capacity as the 'main reasons the plant is in poor condition today.'"

In August, Sen. Alex Padilla (D-Calif.) and the late Sen. Dianne Feinstein (D-Calif.) sent another letter to Senate Majority Leader Chuck Schumer (D-N.Y.) asking to include another $310 million in the then-expected emergency supplemental bill to repair infrastructure needed to treat raw sewage spilling across the border from Mexico.

In their letter, the senators said, "In 2019, the California delegation secured $300 million in the U.S.-Mexico-Canada Agreement to expand the South Bay International Wastewater Treatment Plant from 25 million gallons per day to 50 mgpd which will alleviate the pollution burden. However, the International Boundary and Water Commission and U.S. Environmental Protection Agency have identified urgent repairs to the South Bay International Wastewater Treatment Plant that must be undertaken before expanding capacity."

Of the $300 million appropriated by Congress for expansion of the plant in 2020, the USIBWC now estimates at least half of that is needed for repairs just to get it back normal operation at 25 mgpd. The projects identified to receive the USMCA project money were collection systems, the expansion of the South Bay plant and introducing advanced primary treatment of wastewater that would otherwise go untreated. Other projects were recently identified in treaty negotiations with Mexico.

The San Diego plant is not the only part of the complex, cross-border wastewater treatment system that requires immediate repairs. The Punta Bandera Wastewater Treatment Plant six miles south in Baja California is not currently being used and hasn't been effective at treating wastewater due to its own maintenance problems. It's shut down not because of maintenance, though, but because a critical set of pipes that gets the raw sewage there from Tijuana were damaged in August 2022 due to erosion. 

EPA engineers said the current configuration of the Punta Bandera plant isn't ideal, and it shouldn't be repaired as pumping raw sewage uphill in pipes from Tijuana could lead to similar breaks and environmental damage. 

Commissioner Maria-Elena Giner, appointed by President Biden in 2021 to head the U.S. section of the IBWC, said recently in a video presentation to the California Coastal Commission that her agency has documented $1 billion in work needed to do with only a $50 million budget. 

"We want to achieve our permit compliance within the South Bay within the next nine to 12 months, but we should see incremental improvements along the way, that is our plan," Giner told the commission. IBWC has awarded $10 million in 2023 for rehabilitation and maintenance projects at the South Bay plant including replacement of influent pumps, the cleaning of sedimentation tanks and the replacement of a critical junction box. Giner says the IBWC has identified $100 million to $150 million in urgent rehabilitation projects it needs to complete to get within permit compliance. Mexico is also replacing the 42-in. wastewater line it lost last year and the project is expected to be completed by December.