AUSTIN, TX — Austin Water and city leaders broke ground on the $1.5 billion expansion of the Walnut Creek Wastewater Treatment Plant (WWTP), marking the beginning of key upgrades to critical infrastructure that will improve the treatment processes and protect the health of the Colorado River downstream of Austin, Texas. All improvements will be made while the plant remains fully operational, without interruptions.

“This generational investment to expand and modernize the Walnut Creek Wastewater Treatment Plant is about taking care of Austin,” Austin Mayor Kirk Watson said. “We’re making improvements to keep these essential services strong and building a future we can count on.”

Walnut Creek WWTP continues to stand among the nation’s top-performing plants, earning the National Association of Clean Water Agencies’ Platinum Peak Performance Award. Built in 1977, when Austin’s population was just over 320,000, the plant expanded over time to meet the needs of the growing city, which has more than 1 million people. Today, it serves more than 50 percent of Austin and operates at a treatment capacity of 75 million gallons per day (MGD). Through this expansion, that capacity will increase to 100 MGD — helping meet future demand and state-mandated requirements set by the Texas Commission on Environmental Quality, for Austin’s projected growth of 1.5 million by 2040.
In addition to increased treatment capacity, other significant improvements include:

• Advanced treatment technology to reduce the nutrients that contribute to algae growth and blooms, benefiting the health of the Colorado River
• Replacing chlorine gas with a modern ultraviolet disinfection system, for the safety of workers and the surrounding community
• Advanced odor control technologies, which include biofilters and activated carbon filters
• Construction of a flood wall to protect vital infrastructure during extreme weather
• Modernization to rebuild or replace aging parts of the existing plant and incorporate improved operational and environmental features

Located on FM 969, Walnut Creek WWTP is one of two regional wastewater treatment plants in Austin, treating more than 50 percent of the city’s wastewater. A portion of the treated effluent is reused for irrigation on site and other non-drinking uses through the city’s reclaimed (purple pipe) system, while the rest is safely returned to the Colorado River.

“The health of the Colorado River is tied to the work we do at Walnut Creek, and this expansion project strengthens that connection,” Austin Water Director Shay Ralls Roalson said. “We’re making smart, cost-effective improvements to help protect our environment and provide the reliable services our community depends on every day.” This expansion project will be funded through a combination of federal and state low-interest loans, including up to $1 billion from the U.S. Environmental Protection Agency’s Water Infrastructure Finance and Innovation Act program and $59 million from the Texas Water Development Board Clean Water State Revolving Fund program, along with Austin Water’s funding. Partners of this expansion include: MWH Constructors (construction manager at risk) and AECOM (design engineering).