Phil Dodd
Montpelier’s aging water pipe system has experienced multiple water line breaks and valve failures in recent years, leading to inconvenient boil-water notices, stressful overtime work for city employees, extra expenses for the city, and, in three cases this winter, the flooding of basements or yards.
In addition to those problems, one engineer who lives in Montpelier — Scott Muller — believes pipe leaks, both major and minor, are also undermining city roads, a fair number of which are in poor condition.
Muller is an environmental engineer who has been working for international organizations on urban systems, including water systems, for the past three decades. He has been telling city officials for some time that the city needs to deal with the system’s high pressure, which reaches close to 200 pounds per square inch (psi) downtown, far above the pressure in most cities and well above levels recommended by the state.
“The deplorable state of the streets in Montpelier is a direct result of the over-pressure of the system,” Muller said. The moisture around leaking pipes starts a cycle of freezing and thawing, he said, and also creates cavities that cause roads to collapse or slump.
Muller sent The Bridge a number of articles and studies to support his position that the leaks are affecting the roads. One was a 2014 article in the American Water Works Association Journal entitled “Failure of street pavements resulting from underground water pipeline breaks.” The study “examines the consequences of water main breaks, especially the failure of street pavements caused by the pressure of leaking water and the erosion of pipe bedding,” according to an abstract.
Another article, published in 2021 by an engineering association, has this catchy title: “Mechanistic Mathematical Modelling of Pothole Development from Loss of Roadway Subsurface-Materials.” It suggests that water pressure and erosion of subsurface materials caused by underground leaks can lead to cavity formation, voids, and potholes.
Lost Water
Montpelier does lose more water to leaks than most cities. The Environmental Protection Agency estimated in 2014 that public water systems lose, on average, 17% of their water — mainly from leaks in pipes, according to The New York Times. Montpelier officials say the city’s system loses roughly 30% of its treated water, also mostly to leaks.
The “un-metered” water has to go somewhere, but Public Works Department Director Kurt Motyka does not believe the freeze-thaw cycle is affecting the streets in a significant way. “The water mains are around six feet deep, which is usually below the frost line, he said. “There could be some impact on the roads, but I don’t think it’s a primary contributor to road deterioration because of the depth.”
Motyka acknowledged that “there are cases where water leaks will displace soils resulting in roadway settlement. These areas typically become known leaks and are excavated and repaired.”
While water leaks under the roads could be a factor in the city’s plethora of potholes and rough or slumping pavement, it is also true that the city has not been keeping up with paving needs as described by its own employees.
Department of Public Works Assistant Director Zach Blodgett has recommended for at least the past couple of years that the city spend $1.2 million per year on paving, but the budgets presented to the city council by the city manager and approved by the council in an attempt to keep taxes down have been for far less than that. For Fiscal Year 2026, for example, the city has budgeted $725,000 for paving.
Pressure Reduction Vs. Pipe Replacement
Muller believes Montpelier’s very high water pressure is a major factor causing small and large leaks in the city’s water system. State regulators flagged the high pressure as a serious issue when reviewing the city’s application for a drinking water permit in 2023, but in the end did not require any changes to pressure, instead requiring the city to replace its most problematic pipes at a faster pace.
One way to deal with the pressure, Muller said, is to monitor pressure levels in various locations around the city. “It can then be controlled with a series of valves around the city,” he said. “It would require someone to tweak valves and volumes and pressure across the city, trying to harmonize the distribution system.”
Motyka said the water system’s high pressure levels may contribute to pipe problems, but he maintains that focusing on replacing failing pipes with new and stronger pipes — and increasing their size — is the most efficient response to the leaks.
“Larger pipes don’t change the pressure, but it reduces the velocity in the pipe, which reduces water hammer pressure spiking,” he said. He then recounted an example of how installing new, larger pipes helped in one case.
“We were having a lot of water line breaks on Northfield Street, but also on nearby Colonial Drive,” he said. “In 2016 we upgraded the pipes on Northfield Street from a 6-inch pipe to a 16-inch pipe, and after that all the leaks on Colonial stopped.”
Another solution that could help the pressure situation would be to build a new storage tank near the airport in Berlin to serve the hospital and reduce pressure spikes in the system, Motyka said. The city already has two water storage tanks, one on Towne Hill and another off of Terrace Street.
“If you had a tank feed using gravity, that could eliminate spiking from pump changes when we have a pipe break,” Motyka said. “But that would require a whole new water line from the new tank to the water plant, which would be a pretty big capital investment.”
This story is the third in a series about Montpelier’s water pipes. For other stories in the series see “Water Line Breaks Flooded Three Homes This Winter” and “Montpelier’s Frequent Water Main Breaks Prompt More Questions About City’s Water System Plans”.
