Draft Water System Report Recommends Pipe Replacement Over Water Pressure Reduction

A preliminary study and engineering report by the Dufresne Group recommends that Montpelier focus on replacing about half of its aging water pipes rather than taking steps to reduce the system’s water pressure, which is well above the state recommended level. Replacing the pipes will cost $61.8 million, the report says, and would be necessary even if $19 million was spent on reducing water pressure.

The recommendation endorses the pipe-focused approach that has been taken to date by the Montpelier Department of Public Works (DPW), although the report is only considered 90% complete, in part because the final version could be changed based on comments from the state, which regulates drinking water systems in Vermont. When completed, the report will be presented to the city council. 

Dana Nagy, drinking water community operations section supervisor for the state of Vermont, said that providing state comments and agreeing on changes to the report could take “a couple of months, depending on how the back and forth with the city goes.” In the end, the city “has to come up with an acceptable solution that we can sign off on,” he said. 

The state is unlikely to change the report’s focus on pipe replacement, however, since it has little or no authority when it comes to water pressure. That means that unless the city council goes in a different direction than that recommended by Dufresne, the potential will remain for pressure-reducing valve (PRV) failures and appliance damage, problems that some Montpelier property owners have been experiencing because of high pressure and silt from pipe repairs.

Even without addressing water pressure, the recommended pipe replacement work would be an expensive undertaking for the city, as significant work is needed and the plastic replacement pipes that would be used have doubled in price in the last few years.

“[A] large portion of the water system distribution network is approaching, or has exceeded, its expected useful lifespan,” the draft Dufresne study says. “It is estimated that approximately 11% of distribution mains have exceeded their expected useful lifespan while an additional 35% are expected to exceed their useful lifespan within the next 20 years.” 

“The City of Montpelier requires significant investment in the water distribution network to maintain reliable service,” the report says at another point. “The City should continue to evaluate rates and capital improvement reserves to plan significant water system replacement projects over the next 20 years.”

Twenty years is a shorter timeline than that contained in the city’s existing 50-year plan for replacement of half of the city’s water and sewer pipes, but finishing the $61.8 million worth of work in 20 years, while it might be “prudent,” is not mandated by the report, according to Dufresne Project Manager Stan Welch, one of the report’s authors. However, he said the state could require specific timelines for replacing aged-out pipes.

Department of Public Works Director Kurt Motyka said that while he does not think all of the older pipes need to be replaced within 20 years, the city can easily take care of its pipe deficiencies and replace the pipes that have high-frequency breaks within 20 years, and perhaps, he hopes, within 10 years. 

The city’s existing 50-year plan to replace water and sewer lines, as outlined in a June 2021 memo, calls for spending $83.2 million on water pipe replacement in 50 years to replace half of the city’s 58 miles of water pipes. Replacing all the pipes at that rate would take 100 years, according to Motyka. (The 50-year plan also calls for spending another $83.2 million on the replacement of half of the sewer lines).

Nagy, of the state, has said in the past that the city’s 50-year plan for water pipes is unacceptable in light of frequent water main breaks, which he said could threaten public health. The city has had to issue 60 boil water notices in the past five years because of leaking water mains.

Nagy has also been critical of the city’s elevated water pressure, which can reach 200 pounds per square inch (psi), more than double the highest level recommended by the state and probably the highest in the state, which he thinks could be a partial cause of the city’s frequent leaks. About half of Montpelier’s service area has water pressure above 150 psi, and half below that level, the report indicates. 

However, the state might not be able to force changes to water pressure. The state water supply rule states that the “minimum working pressure in the distribution system should be 35 psi and the normal working pressure should be approximately 60 psi.” Because the rule says “should” instead of “shall,” the state’s authority in this area appears to be limited. That could change if the state ever amends the wording in the rule. 

The reason that Montpelier has such high pressure, particularly in lower elevations of the city, is that the water comes from a water treatment plant that is at a relatively high elevation. Water pressure builds quickly as the water rushes downhill. The high pressure allows water to reach higher elevations in other parts of town, and two large water tanks on upper Terrace Street and Towne Hill help maintain pressure in those areas.

By contrast, Barre’s water source also starts at a high elevation, but it has a two-part water system, one for lower elevations in which measures are taken to lower water pressure, and another for higher elevations, where the pressures are not so great when they reach that elevation, according to Brian Baker, Barre’s director of public works. One way Barre reduces pressure on the lower elevation system is running the water through small turbines that generate electricity.

Pipes or Pressure

The Dufresne report investigated two alternatives for Montpelier’s water system: reducing high pressure services and replacing older water mains with adequate pressure pipes.

For the first alternative, the report looked at reducing the water pressure to 88 psi. This would “reduce the thrust force generated during a high flow demand and decrease the likelihood of breaks associated with water hammer damage,” the report says.

Although pressure reduction to the main zone of the city is possible through the use of pressure-reducing vaults, there are several key areas of the system where water pressure would then be too low, the report says. This would require investing in numerous pumps and possibly more water tanks to keep pressure up at higher elevations.

The report states: “It is also important to consider that although this pressure reduction would likely decrease the number of water main breaks and the volume of lost water through leakage, it would not address the distribution system age and current condition.”

The total cost of the various projects needed to reduce high pressure would be $19,013,000, according to the study.

The second alternative does not include any pressure reduction and instead proposes investment to replace poor condition or aged water distribution piping with modern materials rated for the existing pressures. 

Reduce or Replace

One reason for the leaking water mains in Montpelier is that ductile iron pipes installed starting in the 1970s, which were expected to last 100 years, are failing much sooner than expected. For example, ductile iron pipes installed without an exterior lining system on East State Street in 1988 are now leaking and breaking prematurely, according to the report.

“The likely cause is the presence of acidic soils, and induction of electrical currents generated by electrical services grounded to water services,” the report said. 

Other areas known to have corrosive soils are School Street, Gallison Hill Road, and Mechanic Street. About 34% of the city’s water system is made up of ductile iron.

Dufresne’s conclusion that 46% of the system’s pipes have already or will age out in the next 20 years “is based on a 100-year lifespan for cast iron assets and a reduced 50-year lifespan for ductile iron assets to account for the observed premature failure of ductile iron assets as a result of corrosive soil conditions.”

Other pipes needing replacement are those mains that are less than 8-inches in diameter and are unable to provide the required minimum flow to fire hydrants. In 2015, Dufresne identified the mains needing updating for this reason; the city has since replaced seven of those mains. A table in the report shows another 13 still need upgrading. 

The state, which has jurisdiction over fire hydrant flow, has required the city to submit a detailed plan and schedule for completing the upgrading of mains with fire hydrants. The cost of that remaining work adds up to about $5.5 million.

The total cost estimate for replacing approximately 144,900 linear feet (27.4 miles) of the aged or concerning water mains of various types throughout the distribution system would be $61.8 million. The city has a total of 307,545 linear feet (58 miles) of water pipes.

As a result of the pandemic and inflation, the price of the high-density polyethylene (HDPE) and PVC pipes that would be used for replacement has risen substantially. 

“The price for PVC and HDPE pipe has doubled in the last few years,” according to Devyn Hogan, a salesman at E.J. Prescott, a pipe provider with an office in Barre. “The price has stabilized over the last six months, but I doubt it will go down much.”

Dufresne compared the costs of the two alternatives and found that the pipe replacement alternative was cheaper, since the water pressure reduction alternative would still require pipe replacement on the same scale. It also created a “selection matrix” that concluded the pipe replacement alternative was the best alternative.

However, Dufresne said, the matrix scoring differences “are relatively slight, and it should be noted that these parameters are subjective in nature and different reviewers could rate these items differently … [B]udgetary constraints, funding options, and local preferences may also factor into the City’s decision.”

The report also examines transient pressure issues in the system, such as when fire hydrants are being used. ‘[A] pressure fluctuation during a high demand period is not abnormal, but with aged infrastructure any fluctuation can lead to the generation of forces that could damage failing assets,” the report states. 

Other Solutions

Fluctuations could be reduced by adding another new tank to the system, the report says.

“[O]ne solution the City may elect to pursue would be partnership with the Central Vermont Medical Center (CVMC) to replace their existing water storage tank in poor condition with a water storage tank sized to feed the City, and also provide the required fire protection to the medical center,” Dufresne suggested. 

The total costs of the CVMC tank and new distribution lines would be another $8 million, the report states, which was not included in the $61.8 million pipe replacement cost. It is unclear whether the hospital would share in the cost of the new tank and pipes.

The report concludes by identifying the water pipes in most urgent need of replacement, including pipes on Quesnel Drive, School Street, Walker Terrace, North Street, George Street, Dwinell Street, and Route 2 from Route 302 to Country Club Hill. 

These “high priority” projects, which are a mix of pipes that need to be increased in size for fire hydrant pressure and pipes that are close to failing, could be completed over the next five years at a total cost of $2.3 million, the report says. Dufresne’s Welch said the high priority list was provided by the city.

City Manager Bill Fraser said the city can fund that work as well as another $4 million in priority work over the next five years and stay within the water and sewer fund’s debt and fee policies. The second five-year set of priorities is not laid out in the draft report, but it will be added to Appendix G of the report before the report is complete, according to Welch. 

Fraser said the city will focus on the high-priority projects, but said he thinks the rest of the $61.8 million in pipe replacement could be spread out over a longer time period. Some of the older pipes may not necessarily need to be replaced at the end of their lifespan if they are still working, he said.

Because the Dufresne report was written as a preliminary engineering report, it could be used as the basis for requesting a federal Rural Development loan, a state drinking water revolving fund loan, or using the Vermont Municipal Bond Bank. Motyka said the city is also hopeful there may also be funding opportunities under the recently passed federal infrastructure law.

In addition, the city just applied on March 16 to Sen. Peter Welch for a $3 million Congressional “earmark” to fund water pipe replacement, according to Fraser. Congressional earmarks were banned for a time, but returned two years ago. Fraser cautioned that many municipalities and organizations apply for the earmarks, so they are hard to get. Montpelier applied for other earmarks recently but did not get any, he said.

Editor’s note: This is part three of our series on Montpelier’s water and sewer system. Read part two here, and part one here.