The sewer system for Allenstown and Pembroke is getting an upgrade.
The system, built in 1977 and expanded in 2011 to a capacity of 1.5 million gallons a day, empties into the Suncook River at its confluence with the Merrimack River. The upgrade is expected to start this month and last through summer of 2027, according to Hoyle Tanner, the engineering firm overseeing the project.
The $11 million upgrade is being paid for by the New Hampshire Department of Environmental Services Clean Water State Revolving loan fund, which uses federal funds to pay for wastewater and drinking water projects. It includes two new clarifiers, site improvements, upgrades to sludge pumping capacity and relocation of the plant water system.
Planning for the upgrade has been going on since 2023. The work is being done by Penta Construction of Moultonborough.
The plant is at 35 Canal Street.