Dover's water supply faces challenges as new Pudding Hill plant opens

DOVER — The city's new water treatment facility began its first operation on May 2. It is located in the Pudding Hill aquifer and aims to treat contaminants in water such as metals and PFAS.

Meanwhile, the three wells that used to draw water from the Pudding Hill aquifer are in use again after remaining offline for six years, according to John Storer, directory of the city's Community Services division.

Dover is a city entirely reliant on groundwater. Since the Pudding Hill aquifer was taken offline in 2018 due to severe PFAS contamination, the city has faced water scarcity issues. Storer once proposed initiatives urging water users in the city to conserve water as much as possible in 2022.

Storer told Foster’s Daily Democrat the water supply provided by three wells in this aquifer has not yet returned to previous volumes. It accounts for only about one-tenth of the city’s daily demand.

The day before the water treatment plant started operation, Storer and his team, along with external experts, gave a presentation at a workshop session at the City Council to discuss the challenges and potential issues facing Dover's public water supply system.

Brox Quarry poses a threat to Dover water supply

James Emery, president at Emery & Garret Groundwater Inc., raised concerns about the potential impacts of Brox quarry on Dover’s water sources. Situated on the border of Barrington and Dover, and adjacent to the Hoppers aquifer, this quarry is a large facility and Brox is seeking expansion opportunities.

In December 2020, the Community Services Department of Dover sent a letter to Barrington’s town planner, expressing concerns over a proposed expansion by Sunset Rock LLC (Brox Industries, Inc.). The letter showed the expansion area falls within 500 feet of the Campbell well, a vital water source providing nearly half of Dover’s drinking water. The city of Dover sought to protect the aquifer from potential harm caused by groundwater depletion and contamination, according to the letter.

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Emery noted the New Hampshire Department of Environmental Services (DES) has requested a large groundwater withdrawal permit before excavating and draining the quarry. “We have not heard whether or not Brox will continue with this effort, but I wanted the council to be aware that this is something that we’re monitoring because it has the potential to take one of your wells offline,” Emery warned in the meeting.

Storer told Foster’s that right now the wells and the quarry coexist harmoniously, but the city will watch the issue closely and make sure that the quarry expansion will not impact the wells.

There are two well points in this aquifer. “We run them quite heavily and rely on them extensively,” Storer said. “We can’t afford to lose the production capacity of those wells. That would be a devastating loss for the city.”

Dover seeks to eliminate lead in water lines

As part of its compliance with the improved lead and copper rule, the City of Dover is conducting an inventory of all water service lines connected to its public drinking water system. It involves documenting the materials used in these service lines, such as lead, plastic, or copper.

Amelia DeGrace, Dover's assistant engineer, said the water service line inventory requirement stems from the water crisis in Flint, Michigan, where the water supply led to 100,000 residents getting contaminated water and exposed between 6,000 and 12,000 children to lead.

All public water systems in New Hampshire are required to submit an inventory of the service lines to the Department of Environmental Services by Oct. 16, 2024. The government website states if a lead service line is discovered, it is essential that the entire service line be replaced from the water main to the building, or lead will continue to leach into the drinking water.

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DeGrace said the challenge Doverhas with this service line inventory is time. “If there is an unknown material, we have to treat it as potentially lead and have to notify people by November 15th of this situation. So we are working really hard to reduce our number of unknowns as much as possible.”

While the city is required to notify private owners if lead lines are discovered on their properties, these owners are not obligated to replace the lead lines. DeGrace said, “We reached out to DES to ask about what if a restaurant were to have a lead service line and then refuse to replace it. We haven’t received any comment back on that.”

The city is requesting water system users complete an online survey

Storer told Foster’s that so far they have had a few suspected ones but he was not expecting to come across many of them. The city found one lead service line several years ago when they replaced old water lines downtown that dated back to 1888. He added, “Oftentimes on very old buildings that may not have ever been upgraded, there could still be lead service lines within the building itself.”

The city plans to focus on areas with legacy water mains and the oldest parts of town that have a lot of old cast iron pipes left. Key areas include the streets of Mount Vernon, Atkinson, Bellamy and Cushing. According to the City Council meeting, the city intends to conduct some minor excavations in these areas to see whether there are any errant lead service lines in the area,

Salt and PFAS contamination

Emery told Foster’s sodium and chloride from road salt are the number one groundwater contaminant in New Hampshire, and can adversely impair the drinkability of the water supply. “It’s a human health issue. It’s an environmental issue. It’s also a corrosive issue to equipment, bridges, highways, and things of that sort,” Emery said.

He demonstrated a set of data during the meeting, indicating that in the last several years, the chloride concentration in Smith well has consistently fluctuated around 250 mg/L, which is the secondary maximum contaminant level (SMCL) for chloride. Emery also noted that the sodium concentration, ideally below 100 mg/L, has risen to 200 mg/L. The sodium and chloride concentrations in Cummings Well have also been going up in recent times.

The widespread use of rock salt on roads to remove ice during winter is an important factor that has caused high levels of sodium and chloride concentration in Dover’s water source. According to Emery, Smith well and Cummings well are surrounded by multiple major roads and heavy salt use.

The City Council has approved purchasing commercial brining equipment, including two truck applicators and two sidewalk applicators, so the city can pre-treat the entire area with two trucks in about six hours at a cost of approximately $800, reducing the salt load by 70%-80%, Emery said.

Another significant water quality concern in Dover is PFAS contamination. Emery stated that the Pudding Hill Aquifer was the most heavily impacted by PFAS contamination. For example, take the Ireland Well in this area: since 2016, there have been 42 sampling rounds, with PFAS detected in the water samples during 30 of these rounds.

Being exposed to PFAS can bring various health effects, such as the increased risk of certain cancers, and changes in the immune system and response to certain vaccines, among others.

Storer described it as one of the most frustrating challenges facing the Dover water system: “They’re showing up in products that are getting into the sewer, so we have to deal with that both in our drinking water and wastewater. They’re still getting out there, and we’re gonna be left dealing with them, possibly at all city well sites.”

The encouraging news is that the water treatment plant, located in the area of the Pudding Hill aquifer, started operating May 2. It can not only treat iron and manganese but also remove MTBE, 1,4-dioxane, and PFAS, making it the only facility in the state that performs all of these treatments.

Storer told Foster’s three wells in the Pudding Hill aquifer area have been reactivated, providing water to Dover once again. However, the current output from these three wells only accounts for approximately one-tenth of the city’s daily demand. He emphasized, “We have test results to verify that the treatment is working and PFAS is being removed.”

This article originally appeared on Portsmouth Herald: Dover's water supply faces challenges as new Pudding Hill plant opens