This story was originally produced by the Eagle Tribune. NHPR is republishing it in partnership with the Granite State News Collaborative.
Efforts to clean up contamination in Plaistow’s new drinking water system are ongoing, with involvement from the New Hampshire Department of Environmental Services and Underwood Engineers.
Both agencies helped connect residents to the Southern New Hampshire Regional Water Project in August 2022.
Selectmen asked representatives from both groups to explain why a recent violation notice was triggered.
An order of violation issued Feb. 8 announced that the level of haloacetic acids in Plaistow municipal water exceeded federal standards.
Haloacetic acids, also known as HAA5, are contaminants formed from disinfection products used to clean the water system.
A letter was sent to some residents affected by the violation.
Those residents are upset they weren’t informed of the situation months ago, when they decided to join the waterline.
One frustrated resident felt information was withheld about the contamination when she connected in January.
Another resident, Christine Sciacca, said she’s had to buy bottled water for herself and her pets, causing her to lose trust in the water system.
“The choice for my own health was taken out of my hands,” said Sciacca.
New Hampshire Department of Environmental Services Project Engineer Cynthia Klevens said Plaistow residents have been exposed to the contaminants for five months.
The violation stemmed from an October 2022 reading that showed the contamination level was at 139.4 parts per billion.
The federal standard is 60 parts per billion for a yearly average.
Eugene Forbes, a project engineer at Underwood Engineers, said measures have been taken to reduce the contaminants.
Since October, two other readings show levels are dropping, but still above the acceptable threshold.
Latest results in January show contaminants at 79.7 parts per billion.
Forbes said the system has been increasingly flushed, and the town hired a cleaning company to do a thorough vacuum on Sweet Hill Tank in December.
Forbes said moving forward, officials will conduct weekly tests and increase flushing to get rid of contaminants.
He foresees water quality continuing to improve as more people connect to the pipeline.
He emphasized that when nearby Salem switched to free chlorine to treat its water for a few weeks last month, levels in Plaistow were impacted.
Salem is back to its regular water treatment which should help Plaistow get back on track shortly, according to Forbes.
Selectman Bill Coye asked if there were any health effects associated with drinking the contaminated water.
New Hampshire Department of Environmental Services Toxicologist Jonathan Patali said health effects associated with these contaminants depend on concentration in the water and length of exposure.
If the concentration remains about the standard level for several years, the risks for certain cancers becomes more severe.
Patali said the main way these contaminants can get into residents is through ingestion, like drinking or cooking.
Klevens said that time frame is still considered short-term exposure.
Town Manager Greg Colby is hopeful the town’s contamination level will drop soon. He said weekly testing will continue.
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