Marble Falls scales back wastewater plant to offset rising costs
The One Water wastewater treatment plant rendering which is expected to be complete by May 2029. Courtesy image of the city of Marble Falls.
Marble Falls is making small cuts to its new One Water wastewater treatment plant to offset rising construction costs, though the latest changes still add $88,129.79 to the construction contract.
Marble Falls City Council approved the changes to its contract with MGC Contractors Inc. on Tuesday, Oct. 6, combining cost-cutting measures, which included eliminating a planned odor control system, with additional expenses driven by rising material and equipment prices.
The changes follow a February contract restructuring after the project’s estimated cost rose $34 million, from $87.84 million to approximately $121.84 million.
The latest cost increases stem from tariffs, fuel and equipment prices, and competition for construction resources in the Austin area. Those costs climbed during a nearly six-month gap between the project’s Dec. 4, 2025, contract award and May 28, 2026, notice to proceed, according to the city’s agenda packet.
To help offset the increases, the city is removing the odor control system because nearby land owned by the Lower Colorado River Authority cannot be developed, providing a buffer between the plant and surrounding properties.
The Texas Water Development Board approved its removal, and project engineers determined it would not negatively affect public health or the environment. The system could be added later if funding becomes available.
The alternative concrete coating meets construction standards at a lower cost. Other modifications include additional protective lining for pipes carrying untreated sewage.
The 10 modifications result in a net contract increase after accounting for the cost-saving measures. The additional expense will be covered by the project’s existing contingency fund, leaving approximately $3.14 million available.
The changes will not require additional funding or extend the construction timeline.
Background
The One Water facility, the largest construction project in Marble Falls history, broke ground in May 2025 on city-owned land off Colt Circle Drive, behind Walmart.
The project is among several major city investments contributing to higher property taxes. Marble Falls increased its property tax rate for the 2026-27 fiscal year to help cover debt payments on projects including One Water, a second fire station and downtown improvements.
The plant will replace the city’s more than 70-year-old wastewater facility, which was damaged in the 2018 flood and has struggled to keep pace with population growth. In 2019, the Texas Commission on Environmental Quality required the city to expand its wastewater treatment capacity after the existing plant operated at 75 percent capacity for three consecutive months.
One Water will more than double the city’s treatment capacity to 3 million gallons per day. It also is designed to eventually allow treated wastewater to be reused for irrigation, reducing demand on the city’s drinking water supply.
Originally expected to begin operating by 2028, the project is now scheduled for final completion in May 2029.