Projects to turn wastewater into drinkable water are progressing in San Diego and East County, but their costs have once again spiked.
In East County, a milestone is approaching as a 24-inch pipeline that will transport water from the Advanced Water Purification plant under construction in Santee to the Lake Jennings reservoir in El Cajon is on track to be completed by the end of the month. The entire project is scheduled to be finished by the end of 2026. It will convert 15 million gallons of wastewater a day into enough drinkable water to meet 30% of East County’s demands.
Construction of another stretch of pipeline needed for East County’s and San Diego’s water treatment projects is beginning soon in Mission Trails Regional Park.
Costs of that project recently saw a significant price increase for the city of San Diego’s $5 billion Pure Water sewage recycling system and the $1 billion Advanced Water Purification program.
In January, the San Diego City Council agreed to fund an additional $50 million for a new pipeline and rehabilitation of an existing one. Council members admitted to some sticker shock at the price increase, but voted 8-1 to approve the new agreement, with Councilmember Henry Foster in opposition.
In November, the East County Advanced Water Purification Joint Powers Authority agreed to a $26 million increase for its share of the project.
As explained by Padre Dam Municipal Water District CEO and General Manager Kyle Swanson, a significant part of the cost increase is for the rehabilitation of the 8-mile, 48-inch East Mission Gorge force main line, including a long stretch through Mission Trails Regional Park.
The project includes a new 10-inch line that will carry less than a million gallons a day of residuals that are a byproduct of the Advanced Water Purification plant’s treatment process. The residuals will flow into the city of San Diego’s wastewater line and ultimately to the Point Loma Wastewater Treatment Plant. San Diego agreed to fund part of the project to divert the residuals away from its Pure Water plant.
A second, 27-inch pipeline under construction will be used during storms to prevent an overflow of the gravity line that carries wastewater from East County communities. Both lines will be inside the 48-inch East Mission Gorge force line in Mission Trails Regional Park, and a temporary bypass line will be installed during their construction.
The total costs include $80 million for the residual line, with San Diego assuming about 89% of the cost, and $101.3 million for the East Mission Gorge force main rehabilitation project, with the East County JPA assuming about 60% of the cost.
According to the staff report that went to the San Diego City Council, the latest cost increases were caused by a number of factors, including a new assessment of the condition of the Mission Gorge line and the rising cost of labor and materials.
In discussions about the project, San Diego City Councilmember Raul Campillo said abandoning the project and starting over would be much more costly than the new $50 million bill.
“I understand the significant cost increase for this contract,” he said. “It’s daunting, and it’s not something anybody takes lightly. But I think the context here is incredibly important.”
Construction of the plant was launched in 2021 as the largest infrastructure in San Diego’s history. When completed over two phases in 2035, it’s expected to reduce the city’s share of imported water from about 85% to less than 50%.
Campillo said the residual line and upgrades are crucial to the Pure Water system, and not approving the new agreement could mean abandoning the $1.3 billion already invested and possibly investing $2.5 billion or $4 billion to upgrade the Point Loma Wastewater Treatment Plant to meet standards of the Clean Water Act.
The Pure Water project is intended to make the upgrades unnecessary because sewage from the plant will be purified at a new Miramar plant just east of Interstate 805, then stored in Lake Miramar reservoir near Interstate 15 and later piped to homes and businesses as potable water.
Preliminary construction of the stretch of pipeline through Mission Trails Regional Park is scheduled to begin at the end of this month, which will close vehicle traffic on the two-mile Father Junípero Serra Trail from the visitor’s center to Old Mission Dam for about a week.
More construction is scheduled to begin in the spring, and the road will be closed for vehicle traffic for 14 months but still will be open for hikers and cyclists.
A video describing more details about the park project was posted by East County Advanced Water Purification, and updates on the entire project are posted on the AWP website.
This was not the first significant cost increase to the project, and it wasn’t even the highest. The San Diego City Council approved an additional $130 million to the project in 2021 and another $130 million was added to the cost in 2024.
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