Hooksett officials say Merrimack Street pump station, local pipes at capacity; infrastructure funding planned

Hooksett sewer staff told the Selectboard on Feb. 12 that the Merrimack Street pump station and several downstream pipelines are at capacity, and no additional sewer capacity will be issued for developments in the affected area until a new pipeline is installed.

The lack of capacity affects multiple projects clustered near Merrimack Street and Thompson Avenue, officials said. That group of projects includes the University Heights townhouses (the last 20 of which were already allocated capacity), several proposed apartment projects and a sand-and-gravel developer; one developer who prepaid for more connections will be limited to 50 living units until the piping is upgraded.

The statement from sewer staff followed an update about area development. “There’s no capacity left in that area. There’s a pipeline that needs to be put in before any more building is done in that area,” sewer department staff told the board. The department said the plant can accept additional flow but the limiting factor is pipe size and the Merrimack Street pump station’s receiving capacity.

Why it matters: Without downstream piping improvements, the town cannot authorize additional sewer connections in a cluster of pending projects. Developers who previously bought capacity — in one case for 130 units — will be given far fewer hookups while the pipeline issue is fixed, town staff said.

Details and projects affected - University Heights: staff said the sequence of hookups carved out a final allocation for the last 20 townhouses; the project uses capacity that runs to the Merrimack Street pump station. - Manchester Sand & Gravel and an unnamed sand-and-gravel developer: projects in the same drainage area are competing for limited capacity. - A developer who prepaid for 130 connections will initially be granted 50 living units because of current pipe limitations. - Brady Sullivan: staff said the company has enough capacity for an office building but far less capacity for residential units in the same area.

Sewer staff described a potential fix: a new gravity sewer that would take flow off Merrimack Street pump station and route it directly to the treatment plant, avoiding the need for an additional pump station. “Part of the solution is this new pipe… it’ll be a gravity line all the way to the plant,” sewer staff said, adding the work would take time to design and require coordination with developers.

Funding and the TIF warrant article Selectboard members and staff also discussed a proposed warrant article that would use TIF (Tax Increment Financing) proceeds and wastewater funds to pay for phase-one infrastructure. Town presenters described the warrant as a roughly $10 million package: about $2.1 million from wastewater funds and roughly $7.7 million bonded against TIF proceeds to fund river-crossing piping, a new pump station near Kimbell Drive and force-main upgrades.

The council and budget committee have supported placing the article before voters; officials told the board they will seek voter approval at the upcoming town meeting. One Selectboard member said the article was expected to appear as Article 3 on the March ballot.

Intersection and roadway funding Officials discussed parallel infrastructure needs, including the Martins Ferry/Messier Brook intersection and other roadway projects related to SNHU’s campus and Route 3 improvements. Selectboard members said Southern New Hampshire University declined direct assistance for the Martins Ferry intersection but that town staff had submitted the intersection project for possible congressional direct-spending assistance after an earlier bonding attempt failed to meet a three‑fifths threshold.

State bills and ADU proposals Planning and town staff also flagged state legislation that could change local development pressures. Staff mentioned a proposed ADU (accessory dwelling unit) bill and minimum-lot-size bills and noted that a bill cited in the meeting (referred to as “House Bill 577” in staff remarks) is under review at the state level. Planning staff warned that if ADU or minimum-lot-size mandates pass, sewer capacity problems could be exacerbated because older neighborhoods were designed around existing pipe sizes.

“One option is first‑come, first‑serve for ADU hookups, but we couldn’t hold to that forever,” a planning official said, describing the potential mismatch between state policy and local infrastructure. Sewer staff noted that adding many ADUs in an area without concurrent pipe upgrades would stress neighborhood mains that were not sized for increased loads.

Next steps Town staff said they will continue outreach to developers and will pursue the design and funding steps necessary to build the new pipeline. Officials urged voters to review the warrant article funding the work; the Selectboard and staff said the infrastructure investment is a necessary precondition to authorize additional development in the affected corridor.

No formal vote on project approvals was taken during the Selectboard discussion; the items described were updates and planning-level direction.