Our New Evolution in Wastewater Treatment Is Now Complete
In spring 2023, Regional San completed the EchoWater Project—a
monumental, decade-long expansion of our treatment
plantthat 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
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
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.
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.