This story by Liberty Darr was first published in The Other Paper on April 2, 2026.

In 2023, South Burlington residents approved a $33.8 million bond to pay for three wastewater projects in the city, including upgrades to the city’s aging Bartlett Bay wastewater treatment facility.

Now, three years later, the city needs another $16.4 million to get the projects finished, and voters may be asked later this year to approve the funding.

The largest chunk of the initial bond amount came from upgrades to the Bartlett Bay facility, which is more than half a century old. Built in 1970, its last major upgrade was in 1999. While a typical lifespan of these facilities lasts around 50 years, upgrades are typically necessary after 20 years or so, especially as the city grows and anticipates even more growth, according to city officials.

The facility collects and treats wastewater from about one-third of the city, processing roughly 750,000 gallons of wastewater per day.

“We’re replacing mechanical, electrical process equipment,” Jon Olin, an associate with the engineering firm Hoyle, Tanner & Associates, said of the project. “This also incorporates advanced technologies and upgrades for regulatory requirements. So, the plant is designed for the future of the city and to carry it beyond for the next 30 years.”

The price tag also included upgrades to the Airport Parkway wastewater facility to better manage solids generated from the Bartlett Bay site. That was originally set to cost $1.8 million. A third portion of the project also included upgrades to the Queen City pump stations, which were projected to cost approximately $4.5 million.

But when construction bids were opened in January for the Bartlett Bay facility’s reconstruction, the lowest bid came in $11.6 million higher than previously estimated. Additionally, revised construction estimates for the Airport Parkway project were $400,000 higher.

The Queen City Park pump station project is also now estimated to cost $6.1 million.

Olin said the cost index across the industry has shown that construction costs have increased 50% in the past five years.

“Five years have been as hard as it can be to predict the escalation and inflation that we’ve seen in the industry, and it’s been across all sectors of the public industry,” Olin said.

“It’s not ideal,” he added. “I don’t want to be here telling you that the project came in 40% over what my team estimated.”

With all these factors combined, including construction and engineering fees, the project is roughly $18 million higher than what was bonded for in 2023. However, the city could leverage roughly $1.8 million from wastewater reserves to cover a portion of cost overages.

Still, the project’s new price tag will likely translate into steep wastewater rate increases for city residents. In simple terms, the annual payment on an additional $16.4 million loan would increase annual payments by about $1 million over the life of a 20-year loan.

According to estimates provided by Public Works Director Tom DiPietro, with an additional $16.4 million loan, residents could see an 11.7% increase in wastewater rates in Fiscal Year 2028, with ensuing years leveling down to around a 10% increase, landing at 9% higher in Fiscal Year 2033.

While the City Council made no concrete decision on whether to go out to bond or value engineer the project for cost savings, city officials say the best course of action is to bring it back to voters.

Additionally, re-engineering the project to find cost savings could mean removing key elements that would just need to be fixed later. This could be more expensive in the long run, officials said.

“If we change the project design, we have to go back through the kind of gauntlet of permitting that the project had to go through originally,” DiPietro said. “So, if we start moving things around or eliminating, we’d have to go back, not just locally, but potentially (to) some other state permits that were issued.”

A lot of behind-the-scenes work still needs to be completed by city officials, but the City Council is anticipated to take up the issue again soon.