EchoWater Project

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Our New Evolution in Wastewater Treatment Is Now Complete

Aerial photo of the treatment plant

In spring 2023, Regional San completed the EchoWater Project—a monumental, decade-long expansion of our treatment plant that takes our region’s wastewater treatment to a whole new level. The project was completed under budget and on schedule to meet strict regulatory mandates. The new tertiary treatment process now removes 99 percent of ammonia and 89 percent of nitrogen from the wastewater. With this upgrade, the treatment plant has been renamed the EchoWater Resource Recovery Facility.

The result of this landmark $1.7 billion upgrade is cleaner treated water for discharge to the Sacramento River, which benefits the Sacramento-San Joaquin Delta downstream. The expansion also provides a drought-resistant source of recycled water for non-potable uses—like irrigating local agriculture and supporting habitat land for Regional San’s landmark Harvest Water program.

The EchoWater Project was among the largest public works projects in Sacramento’s history. With its nutrient removal and tertiary treatment facilities, the expanded treatment plant is the second largest of its kind in the nation.

The Road to EchoWater

The EchoWater Project began in 2010 when the Central Valley Regional Water Quality Control Board issued new treatment requirements in Regional San’s wastewater discharge permit. The Board took that action to improve water quality and help alleviate ecological problems in the Delta.

Regional San tested many possible treatment strategies to meet the new permit requirements. Once a specific strategy was selected, engineering designs were completed and construction began. The massive upgrade consisted of 22 individual projects that together used 41,350 tons of steel and more than 225,000 cubic yards of concrete.

The centerpiece of the upgrade was the Biological Nutrient Removal (BNR) Project—the heart of the new treatment process. BNR is a sprawling complex, roughly equivalent in size to 18 football fields.

To complete the upgrade to tertiary treatment, the plant also now has a granular media filtration system that removes smaller particles and a larger amount of bacteria and viruses from the effluent compared to secondary treatment. Additional liquid chlorine disinfection inactivates any bacteria and viruses that may remain after filtration.

Containing Costs

Original estimates projected EchoWater to cost as much as $2.1 billion to design and construct. Regional San worked hard to implement efficiencies that helped keep the final cost to about $1.7 billion—reducing the impact to customers’ rates. The project also received nearly $1.6 billion in low-interest financing from the state’s Clean Water State Revolving Fund, which saved ratepayers more than a half-billion dollars in interest costs.


Press Release – May 15, 2023: Regional San’s monumental wastewater treatment plant expansion project delivered ON schedule and UNDER budget

EchoWater Fast Facts

Infographic with various statistics about the project

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