But city officials stressed drinking water wells were shut off well before it reached, and now exceeded, the EPA recommended advisory levels of safe drinking water.
City officials and the consultants contracted to monitor the drinking water have been keeping watch on contaminant levels at the monitoring sites and in the drinking wells, Storer said.
When the Ireland Well in the Pudding Hill Aquifer recorded a concentration of 48 parts per trillion of PFOA and PFOS parts per trillion on June 28, the decision was made stop drawing water from the well, Storer said.
PFOA stands for perfluorooctanoic acid; PFOS stands for perfluorooctanesulfonic acid; and PFHpA stands for perfluoroheptanoic acid — all human-made chemicals.
Storer said the Ireland Well had recently been recording levels of between 6-10 ppt.
He said while he would love to have zero level, it is just not realistic.
Storer said a recently dug well, known as Dover Pudding Hill 1 (DPH1) in the Pudding Hill Aquifer, was shut off as a precautionary measure until hydrologists can confirm that using the well isn’t sucking the plume towards it.
When online, the Pudding Hill Aquifer can provide about 1 million gallons of water per day, Storer said.
Still, without Pudding Hill, the city has a supply capacity of approximately 5 million gallons of water a day, Storer said.
Because of the contamination issue and because the region is considered in a moderate drought by the U.S. Drought Monitor, Joyal encouraged residents and businesses to be conscientious with their water usage.