Southern New Hampshire Regional Water Project

Dec. 28, 2021

Cost: $40 million
Location: Manchester, Derry, Salem, Windham, Hampstead, Atkinson and Plaistow, New Hampshire
Year: 2021-12-21
Size: 3.13 mgd
Owner: Manchester Water Works, Towns of Derry, Windham, Salem, Plaistow, Pennichuck Corporation, & the Hampstead Area Water Company Inc. Manchester, Derry, Salem, Windham, Hampstead, Atkinson, and Plaistow, New Hampshire
Designers: Underwood Engineers Weston & Sampson Lewis Engineers
Contractor: Defelice Corporation: Lewis Builders Development Inc. dba HAWSCO Revoli Construction American Excavating DN Tanks

The Southern New Hampshire Regional Water Project is a collaboration between seven communities and water companies: Manchester Water Works; the towns of Derry, Windham, Salem, and Plaistow; Pennichuck Corporation; and the Hampstead Area Water Company Inc.

This project aimed to supplement stressed drinking water resources in southern New Hampshire. Water recipients are primarily in need of supplemental drinking water due to methyl-t-butyl ether (MtBE) contamination of local wells and the region’s growing population. It is New Hampshire’s largest regional water distribution system interconnection, connecting six large water systems. These systems are designed to provide up to 3.13 mgd of safe, reliable drinking water to the water recipients. Construction is underway for Phase 1 of the project, encompassing 1 mgd.

The state of New Hampshire sued 22 gasoline manufacturers and refiners for damages in connection with the statewide contamination of groundwater with the gasoline additive MtBE in 2003. This resulted in the conceptualization of a drinking water infrastructure project interconnecting the six communities in southern New Hampshire with a regional water line. 

The lawsuit was settled with all but one of the defendants from 2013 to 2016, obtaining approximately $82 million as a result. These funds formed the State’s MtBE Settlement Funds, and received verdict monies from the remaining defendant, ExxonMobil Crop., of approximately $307 million, of which 90% formed the Drinking Water and Groundwater Trust Fund (DWGTF). 

In 2018, the Drinking Water and Groundwater Advisory Commission, which oversees the DWGTF, approved an appropriation of $19.6 million in grant funds for capital improvements necessitated by the project. The project would address the construction work in two phases: phase 1 is focused on completing the design and construction of the infrastructure necessary to deliver up to 1 mgd; phase 2 increased capacity up to 3.13 mgd while addressing additional infrastructure needs and upgrades to deliver the full design flow.

After MtBE Settlement funds were received, preliminary design work determined the most feasible approach to deliver safe and reliable drinking water to the southern region of the state. The MtBE impacts to private wells in Windham and Plaistow were examined, as well as the loss of significant supply capacity in Salem due to MtBE contamination of two water supply wells. 

The Southern Interconnection Agreement (SIA) was established to outline the roles and responsibilities of each party involved in the project. Before the SIA was drafted, a Memorandum of Understanding (MOU) was developed for the project and executed in October 2018. Phase I of the project is nearing completion with funding for engineering and construction provided by the DWGTF and MtBE Settlement funds. 

The water recipients will receive a total of up to 1 mgd of water per day from 2020 to 2023 and up to 3.13 mgd at the completion of Phase 2.

Project Year: 2021-12-21Contractor: Defelice Corporation: Lewis Builders Development Inc. dba HAWSCO Revoli Construction American Excavating DN TanksDesigners: Underwood Engineers Weston & Sampson Lewis EngineersOwner: Manchester Water Works, Towns of Derry, Windham, Salem, Plaistow, Pennichuck Corporation, & the Hampstead Area Water Company Inc. Manchester, Derry, Salem, Windham, Hampstead, Atkinson, and Plaistow, New HampshireLocation: Manchester, Derry, Salem, Windham, Hampstead, Atkinson and Plaistow, New HampshireCost: $40 millionSize: 3.13 mgd