San Diego may scale back its ambitious pure water and wastewater purification plans or scrap some of them entirely

San Diego

Work is more than halfway complete on the first phase of San Diego’s pure water wastewater recycling system, and city officials say they are considering major changes to how the second phase will be handled.

Construction on the first phase continues to overcome obstacles such as flooding at the pump station and impenetrable boulders at the tunnel site, and is on track to be completed by the end of 2027.

But plans for the second phase were mostly developed 13 years ago and could change significantly based on new state regulations and new information about how much purified water the city expects to need.

Amy Dorman, assistant director of the city’s Department of Public Utilities, said all parts of the second phase plan are now being considered.

Populations, wastewater flows, water demand projections and regulations have all changed significantly since the original plan was completed in 2011, she said. It won’t be starting from scratch, but we will re-evaluate the plan based on these and other factors.

One thing that won’t change in Phase 2 is the construction of a small demonstration facility that requires state approval at the Point Loma Wastewater Treatment Plant. In fact, it’s already under construction.

But the city may abandon plans to build a second-phase purification plant on 17 acres of vacant land in Mission Valley and plan to store the plant’s purified water in Lake Murray or the San Vicente Reservoir.

It’s unclear what other sites the city could use to build purification plants. Land is scarce in large areas of San Diego, and the purification plant must be relatively close to the Point Loma Treatment Plant because that will be the source of the sewage it purifies.

San Diego recently hired Stantec Engineering Consultants to help evaluate previous Phase 2 plans and recommend any appropriate changes. These measures may include reducing phase two ambitions.

Pure Water plans to provide 30 million gallons of drinking water per day in the first phase and 53 million gallons per day in the second phase.

When the City Council approved the purified water project a decade ago, it was expected that the 83 million gallons of daily production would account for one-third of the city’s drinking water supply.

But thanks to improved water conservation efforts, latest projections suggest that purified water will account for nearly half of the city’s drinking water supply between 2035 and 2040.

Dorman said phase two decisions will take time.

“Due to the scale and complexity of phase two, we expect the reassessment to take at least 12 months,” she said.

Meanwhile, work on the first phase continues apace.

City officials said last week they had finally solved flooding problems at a large sewage pumping station on Morena Boulevard by completing a secant wall, essentially a dam around the pumping station.

Another major problem is impenetrable boulders where the city wants to build a pipeline tunnel under Interstate 805 near Executive Drive.

The city is addressing issues that halted tunnel construction last August due to boulders by switching to microtunnels and adding a second crew.

City officials said the boulder issue won’t slow down Pure Water’s overall construction schedule because a second crew will handle tunneling in Rose Canyon and San Clemente Canyon so the first crew can focus on I -805 Highway.

Delays caused by flooding and boulders could jeopardize the entire system, whose 10 components need to work together like a carefully choreographed ballet.

Due to flooding delays, the city has scaled back Pure Water’s drinking water production from 30 million gallons per day to 7.5 million gallons per day when it is expected to begin operations in mid-to-late 2026.

The system is expected to reach full capacity later in 2027, when pumping stations delayed by flooding are completed.

Flooding and boulder problems added millions of dollars to the total cost of the first phase, reducing the emergency budget reserved by city officials. Flood damage was approximately $26 million, and boulder damage was approximately $8.5 million.

The city has set aside $114.7 million in contingency funds for the nearly $1.2 billion first phase of the project, of which about $68.4 million has been spent. The first phase is now more than halfway complete, and the city has used less than 60 percent of its emergency fund.

Other recent milestones include the completion of tunneling at the bottom of Lake Miramar in Scripps Ranch, where the city will store water from the Phase 1 purification plant being built west of Miramar.

All major structural work on the purification plant has been completed and piping and equipment installation can begin.

At the North City Recycling Plant, where sewage and other wastewater will be treated before entering the purification plant, crews have built two secondary clarifiers, each with a capacity of 2.5 million gallons, and plan to build two more.

The pipeline project will ultimately total 30 miles, with 40% of 12 miles currently complete. It affects the communities of Claremont, Bayfront Park, College Station, Miramar and Scripps Ranch.

Most of the remaining work is planned north of Interstate 52 in College Station.

Councilor Jennifer Campbell, whose district includes all of Claremont, thanked residents for their patience and cooperation during last week’s council environment committee meeting.

She said they’ve had to give up parking spaces and sometimes even sleep, but they’ve taken it really well.

Councilmember Marni von Wilpert praised Pure Water as one of the most climate-resilient projects in the state. She said the cost overrun was disappointing but understandable given the complexity of the project, which is the largest in the city’s history.