More than six miles of shoreline along San Diego Bay have been posted with warning signs after an estimated 500,000 gallons of sewage spilled Monday following a sensor malfunction at a wastewater pumping station.
Untreated wastewater flowed out of manholes into streets and storm drains in downtown San Diego and the Midway District after Pump Station 2 near San Diego International Airport — which sends wastewater to the treatment plant in Point Loma — shut down for nearly a half-hour.
Three other sewage spills also were reported in the county on Monday.
“The malfunction caused the wastewater pumps to shut down. As a result, wastewater backed up in the system and there were spills in various locations in the Midway and Downtown areas that flow into San Diego Bay,” city spokesperson Arian Collins said in an email.
The pumps shut down around 2:50 p.m. They were manually restarted 27 minutes later, but by then, wastewater had backed up in the system.
Customers in 18 locations in downtown San Diego and the Midway District reported issues created by the spill, Collins said. When sewage backups occur, Collins said, “it comes out of the manholes and it goes into the storm drains.”
He said cleanup work began Monday. He was unsure if the work was continuing Wednesday.
The sewage spill fouled a section of San Diego Bay and prompted county officials to post closure signs from Chollas Creek near Barrio Logan north to Shelter Island, county officials said.
Heavy rains caused other smaller sewage spills Monday, as manhole covers overflowed. That included 29,000 gallons of sewage in Bonita that closed Morrison Pond, 21,000 gallons in Spring Valley that flowed into the Sweetwater Reservoir and a spill in San Marcos that closed beach access around Batiquitos Lagoon State Marine Conservation Area.
The closures will remain intact until daily testing shows the bacteria is within state-allowed thresholds.
Residential and commercial customers who were impacted by the sewage spill were told to call city officials at (619) 515-3525. Collins said city staff members are investigating what caused the sensor to fail.
Collins said officials initially estimated the sewage spill at 500,000 gallons, but he said that number could increase as they investigate further.
“By the end of the week, City crews will have a final estimate of the number of gallons spilled. Our initial estimate is that the spill accounts for roughly 6% of the total amount of wastewater treated Monday at the Point Loma Wastewater Treatment Plant,” Collins said in an email.