Neighbors got an apology Thursday about the process of developing an empty, Cambridge-owned acre at 135 Sherman St. to take a giant, buried water storage tank, but no sign the plan wasn’t happening.
There was nearly as much quiet confidence from city staff that the land above would be used as a Public Works facility, likely for the parks and forestry divisions, though John Nardone, that department’s commissioner, told residents at a community meeting that “nothing’s been set in stone.”
He did point them back to the meeting in August 2023 at which city councillors approved buying the former school parking lot for $8.3 million.
“We may have gotten off on the wrong foot, and I will take responsibility for that. I assumed that people already knew that sewer and stormwater work was one of the reasons that the city had purchased this property,” Nardone said.
Still, while the DPW and tank uses were made explicit before the 2023 vote, Nardone admitted: “There was also a clear commitment to involving the community in decisions about the site.”
Where Nardone and other officials dug in was that placement of infrastructure such as a tank was decided by staff, and public discussion was about impacts and making the process as tolerable as possible. “We are not really looking for people’s input in [infrastructure] design,” Nardone said.
The CSO problem
The lot would be dug up and a concrete tank about 170 feet long by 70 feet wide would be settled within to hold 2.1 million gallons. That can help avoid Combined Sewer Overflows, which dump waste into Alewife Brook and other public waters when the city’s remaining 19th century infrastructure gets overwhelmed – a growing threat as climate change accelerates. The CSOs keep waste from backing up into people’s homes but have become the area’s biggest ecological problem. The past six years have seen from seven to 20 discharges, senior project manager Lucica Hiller said. The average year sees 11.2 million gallons of waste spewed, the equivalent of 17 Olympic-sized pools.
“We’re talking about sewage, E. coli, things that are not good for the environment, the ecosystem, the water quality. It’s a public health issue,” Hiller said.
Cambridge, Somerville and the Massachusetts Water Resources Authority have submitted a draft control plan to the federal Environmental Protection Agency and state Department of Environmental Protection, but that doesn’t mean the problem will be fixed anytime soon. After decades, Cambridge is around 55 percent separated in its water and sewer infrastructure, Hiller said.
Faster, but still impacts
A full CSO solution in Cambridge could cost $400 million and take 20 years to finish, said Jim Wilcox, a city engineer.
The Sherman Street tank will play a role in CSO management, but can help keep the discharges from happening on a faster timeline: Construction could start in the summer of 2027 and be finished within two and a half years for an estimated $36 million.
“There will definitely be impacts that will be felt by the people that live in the area,” Wilcox acknowledged, citing excavation vibrations, noise, dust, air quality and traffic from the trucking of soil away from the site and trucking in of construction materials. The city would work with whatever contractor is hired to avoid using Sherman Street as a staging area; as one resident put it Thursday, traffic there is already “a catastrophe.” Residents were also concerned about the return of piercing train whistles with the new activity taking place around rail tracks.
One of many storage tanks
Placement of a water tank on Sherman Street puts it near the city’s most active outfall site, a regulator called Cam401A. That’s ideal, Wilcox said, “because these CSO holding facilities are much more effective when they are close to the regulator structure.”
There are 13 other water tanks around the city. Cambridge seizes on large construction projects as a chance to install them, such as under Parking Lot 6 on Bishop Allen Drive in Central Square, where the Market Central apartment complex was built between 2017 and 2020. There’s a 1 million gallon holding tank at the Tobin Montessori and Darby Vassall Upper School, which opened in West Cambridge in 2025.
Meanwhile, CSO work continues on Broadway in Kendall Square, and $188 million in sewer separation work is planned over the next five years, including on Hampshire Street and Western Avenue and in the Baldwin neighborhood, Wilcox said.
Residents remember promises
Residents were bitter about the coming years of construction and cynical about how the project came together, especially as some saw unfulfilled assurances from the 2023 meeting.
“Specific promises were made that the community would get input in what was going to go there. We were also promised that this community involvement was going to start in early 2024, and a number of City Council members in their comments at that meeting cited this public process as a reason why they supported it,” resident Jennifer Wade said.
The 2023 meeting seemed to go in two directions. Councillors and city staff did talk repeatedly about a public process (“We are committed to have a longer conversation before major decisions are made to work through actually what this is,” city manager Yi-An Huang said), but alongside repeated references to the site’s use for Public Works. The tank was brought up early and explicitly by then deputy city manager Owen O’Riordan (“Regardless as to whether we ultimately end up using this for affordable housing or for DPW purposes, we believe that we can accommodate the stormwater and sewer system controls in this space”) and drew no questions.
Use of the space for affordable housing was brought up repeatedly, but almost wholly in the negative, with Sherman Street rejected as a sensible location for it by residents and at least one city councillor. On Thursday, affordable housing was barely mentioned. There was one reference to use as open space.
“I did go back and I did look at that [2023] meeting,” Nardone said to Wade. “I thought it was pretty clear that then deputy city manager O’Riordan talked about sewer separation at that location, and the importance.”
“We are trying to do better with communication,” Nardone said.
Wade said Friday that the neighbors were left frustrated by the meeting the previous day. A community pop-up for the tank is expected in June, though first comes a meeting about the combined CSO plan that is scheduled for Tuesday. The Sherman Street project has a website here.
This post was updated May 31, 2026, to remove some references to stormwater and replace some with refererences to a combined sewer overflow use for an underground tank.
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