Trenton Water Works Takes Interim Measures While Independent Engineers Review Raw Water Intake Performance

Trenton, NJ — Trenton Water Works (TWW) announced today that it will deploy three high-capacity pumps at its Route 29 South water filtration plant as a precautionary, interim measure to ensure uninterrupted water service to more than 200,000 customers across its five-municipality service area during periods of extreme cold.

The temporary pumping system will allow operators, if necessary, to bypass the plant’s submerged raw water intake in the Delaware River and deliver raw water directly into the treatment process. TWW implemented a similar strategy during extreme cold weather last winter after slushy frazil ice impeded the intake’s performance.

“This is not our preferred method of operation, but it is the most reliable way to ensure continuity of service while we complete a comprehensive, independent evaluation of the intake system,” said Sean Semple, Director of the City’s Department of Water and Sewer, which operates Trenton Water Works. “Protecting our customers’ water supply remains our top priority.”

From January 15 through March 7, 2025, TWW operators were required to bypass the intake and utilize diesel-powered pumps after frazil ice clogged multiple intake screens, reducing the system’s capacity. That approach—approved by the New Jersey Department of Environmental Protection—allowed the plant to continue producing approximately 33 million gallons of drinking water per day while maintaining nearly three days of reservoir storage.

The current intake system, completed in 2022 at a cost of approximately $9 million, was designed by engineering firm Mott MacDonald to replace a concrete intake that had been in service since 1954. The project was intended to improve resilience, including during cold-weather conditions. However, operational data, inspections, and consultations with subject-matter experts indicate that the intake’s performance during extreme cold did not meet expectations.

Based on this review, TWW has found no evidence that operator actions caused the reduced performance observed last winter. Rather, the conditions experienced revealed design and system limitations that were not fully anticipated in the intake’s current configuration.

Last month, TWW issued a request for proposals seeking an independent engineering firm with experience designing and evaluating river-based surface water intakes in cold-weather climates. The selected firm will assess the intake’s design, construction, and hydraulic performance and recommend necessary modifications or supplemental systems to ensure long-term reliability, a multi-year project.

TWW has briefed NJDEP on its winter operations plan and will continue to coordinate closely with regulators while advancing permanent improvements to the intake system. The utility remains committed to transparency, operational accountability, and the delivery of safe, reliable drinking water to the communities it serves.