Report: Chatham Should Investigate More Drinking Water Sources

CHATHAM – While the town’s drinking water system is able to keep up with peak summer demand, additional water supply sources should be sought to ensure there is enough water available should one or more wells be shut down, a consultant has recommended.

That’s not an unlikely scenario. A few years ago, two wells were taken offline after PFAS contamination was discovered in the water. A long-dormant well had to be restarted to augment the water supply.

The town should also consider additional conservation measures to reduce water use, according to an updated water system analysis by consultant Weston and Sampson.

“We think you need to start looking for another source,” Leah Stanton of Weston and Sampson told the select board Sept. 24. The process of developing a new drinking water well can take three to five years, she added.

Conservation is also a key in controlling water use. When mandatory outdoor watering restrictions were in place during recent droughts, use dropped by more than a half million gallons a day.

“This will help to manage the water demands during dry summertime conditions, when both people are using the most water and the aquifer is at its lowest,” said Weston and Sampson’s Cassandra Albrecht.

The town has 11 groundwater wells, two storage tanks, two emergency interconnections with other water systems, and one water treatment plant. One well is not yet online, and a second  water treatment plant is under construction to treat the two Training Field Road wells for PFAS and iron and manganese. The average daily demand for water has remained fairly consistent over the years, the consultants said, but maximum demands, concentrated between May and October, can fluctuate significantly depending upon environmental conditions.

Those factors are expected to continue, but could be impacted by the town’s goal of creating 200 more housing units over the five years. However, peak summer usage is a bigger issue.

“It’s important we focus on those summer months when we’re considering water availability in Chatham,” Albrecht said. With all wells online, the system has a capacity of 4.1 million gallons per day. The typical maximum demand is four million gallons per day. If the largest-volume well becomes unavailable, the system’s capacity would shrink to 3.58 million gallons per day and be unable to meet the maximum daily demand. 

Based on previous years when mandatory outdoor watering restrictions were in place, keeping those bans in place could save 0.62 million gallons per day. The system would then be able to meet the maximum demand if the largest volume well were unavailable.

A new state Water Management Act permit currently pending may require restrictions during certain conditions, Albrecht said.

The situation poses the question of how much the town needs to invest in infrastructure to accommodate the summer population increase, said Select Board member Dean Nicastro.

“This year was the most challenging for a year rounder or even a summer resident in this town, traffic wise,” he said. “Walking down Main Street, we had more people than I think the town can handle. Are we sort of chasing a never-ending proposition here?”

There isn’t a large enough margin with the current wells, he said, and the town should begin “pretty quickly” looking for additional sources. Select board member Jeff Dykens concurred.

“I think we ought to alway be pushing the envelope in terms of new water sources,” he said.

The current margin between capacity and demand is inadequate, agreed chair Michael Schell. “It actually is a little bit scary,” he said. The town should continue its efforts to remove private irrigation systems from the public water system.

“We are paying in capital and operating costs to maintain that top level capacity,” he said, “which means we shouldn’t be paying for equipment and infrastructure for people to water their lawns. That’s an inescapable conclusion.”

The board took no formal action on the report, which will now go before the water and sewer advisory committee.