Austin breaks ground on $1.5B Walnut Creek WWTP expansion

Austin Water and city leaders have broken ground on a $1.5 billion expansion of the Walnut Creek Wastewater Treatment Plant, launching a major infrastructure project aimed at increasing capacity and improving treatment performance while the facility remains fully operational.

The project will expand the plant’s capacity from 75 million gallons per day (MGD) to 100 MGD, helping meet future demand as Austin’s population continues to grow. Built in 1977, the facility currently treats more than half of the city’s wastewater and has earned top performance recognition from the National Association of Clean Water Agencies.

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

Planned upgrades include advanced nutrient removal to reduce algae-forming pollutants in the Colorado River, conversion from chlorine gas to ultraviolet disinfection, enhanced odor control systems and construction of a flood wall to improve resilience during extreme weather. The project will also modernize aging infrastructure across the facility.

“The health of the Colorado River is tied to the work we do at Walnut Creek, and this expansion project strengthens that connection,” said Austin Water Director Shay Ralls Roalson in a press release. “We’re making smart, cost-effective improvements to help protect our environment and provide the reliable services our community depends on every day.”

Funding for the project includes up to $1 billion from the U.S. Environmental Protection Agency’s Water Infrastructure Finance and Innovation Act (WIFIA) program and $59 million from the Texas Water Development Board’s Clean Water State Revolving Fund, alongside local investment.