In 2018, a cluster of southern New Hampshire towns decided to join forces on drinking water. The proposal: to connect their water systems with the city of Manchester to allow more than 1 million gallons of water to flow to the towns per day.
The project, which involved Atkinson, Derry, Hampstead, Plaistow Salem, and Windham, was designed to address an acute problem: the contamination of wells in those towns by methyl-tert-butyl ether, or MTBE, an ingredient of gasoline that had seeped into the groundwater due to leaky storage. A 2003 lawsuit brought by the state against 22 gasoline manufacturers had secured settlement funds that helped pay for the $20 million water infrastructure project.
But some now point to that collaboration — the largest of its kind in the state — as a template to address a thorny problem. As lawmakers and state officials seek to encourage housing construction to address deep shortages, some are pointing to a less discussed problem: access to water and sewer capacity.
In October, St. Anselm College unveiled an update to the New Hampshire Zoning Atlas — the interactive tool first launched in 2023 to compare towns’ zoning restrictions. The latest version of the tool depicts which areas of cities and towns have access to water lines, sewer lines, or both.
And the researchers behind the atlas uncovered a revealing statistic: Just 12% of the state’s buildable land has access to either water or sewer services, and just 5.6% has access to both.
That poses a major limitation for developers.
“When we talk about density, we’re talking about how many units can you put on an acre,” said Preston Hunter, vice president of business development at PROCON, a Hooksett construction management firm, speaking at a presentation of the Atlas in October. “And there’s really two major determining factors there. One is zoning, and the other is the availability of sewer and water.”
In the southern part of the state, water can be particularly fraught. “A big issue we see is access to water,” Deshaies said. “There’s just not always enough groundwater to sustain more dense or larger developments that are being proposed.”
But each town has its own unique problems.
Housing policy experts point to some solutions. Alternative septic technology such as aerobic treatment systems, which use bacteria to break down waste in places with poor soil conditions, could allow property owners to develop housing in hard-to-reach areas, noted Elissa Margolis, director of the St. Anselm Initiative for Housing Policy and Practice. And community septic systems could allow more creative approaches at scale, she added.
But the biggest barrier often lies with the capacity of the existing infrastructure in a city or town. And just having access to water and sewer does not fix all problems, said Margaret Brynes, executive director of the New Hampshire Municipal Association.
“Even when you look at land that can be developed that is on public water and sewer, you have to keep in mind capacity,” Byrnes said in an interview. “It’s not unlimited just because you have a public system.”
One significant problem for municipalities is the age of their infrastructure. Simply maintaining it can be costly, let alone upgrades, said Brodie Deshaies, a legislative advocate at the Municipal Association. Many cities and towns are facing the need to improve the flow rate of their existing facilities before additional capacity is realistic.
“We have members that struggle to be able to afford the upkeep with the continued downward pressure that’s caused by inflation, increased cost of living, and property taxes that fund the majority of services and infrastructure in the state,” Deshaies said.
Deterioration may force some towns to replace their pipes. But if they want to meaningfully expand their services, they might need to widen the pipes, an even more expensive prospect, said Deshaies.
Meanwhile, water access poses its own conundrum: Cities and towns that draw on bodies of water for their water source are limited in how much they can draw by the state Department of Environmental Services. They also face limits on where and how much wastewater they can expel.
Any solution is likely to require residents of a town to approve a large municipal bond to pay for it via a supermajority vote, at a time when property taxes are already high.
Researchers behind the St. Anselm atlas hope that it will provide developers, municipalities, state officials, and lawmakers with a clearer understanding of where housing is possible — and where more needs to be done.
“It can help us understand more globally what types of investments might be needed and might be supported, especially for communities that clearly want more housing, but they’re constrained by the lack of infrastructure,” said Heather Shank, director of the Division of Planning and Community Development at the state Department of Business and Economic Affairs.
The update to the atlas comes as legislators have passed a number of laws to prevent municipalities from imposing restrictions on housing in the last year. Housing advocates have said the laws are meant to eliminate road blocks to necessary development amid the state’s housing shortage.
But if more is not done to help cities and towns expand their water and sewer capacity, the Municipal Association argues, local governments will be forced to make hard decisions.
“What will end up happening, in some cases, is they will either place a moratorium on building to update their zoning . . . to try to address (that) overburdening of infrastructure, or they will have to stop hooking up people to water and sewer,” Deshaies said.
Lawmakers are introducing some bills for the 2026 session aimed at expanding water and sewer access. Rep. Joe Sweeney, a Salem Republican, is bringing forward legislation to enable “special assessment districts” that could allow municipalities to pay for infrastructure improvements through special tax arrangements on developers. Rep. Chris Muns, a Hampton Democrat, has introduced a bill to levy a statewide tax on second homes to pay for housing funding. And Rep. Daniel Veilleux, an Amherst Democrat, is sponsoring legislation “encouraging municipalities with sewage systems to extend system service to neighboring communities.”
The NHMA opposed many of the zoning overhaul laws signed by Ayotte this year, arguing that municipalities should be allowed to move forward on housing intentionally. That should be ideally be done by creating a master plan for new developments and orienting any needed infrastructure upgrades to that plan, Deshaies says.
But on the question of water and sewer, housing advocates and municipalities appear to agree.
“It might seem as if we got rid of all this ‘red tape’ and that’s going to incentivize building,” said Deshaies. “Without the infrastructure, these units still aren’t going to get built.”
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