The boil water order for Oak Bluffs was lifted at 11:30 Wednesday morning.
The state Department of Environmental Protection lifted the order and has shut down the Lagoon Pond well, Paul Provost, interim superintendent for the town water district, said.
He said chlorine is being added to the Farm Neck well, which is closest to the water tank. Residents might notice that the water has a slight taste of chlorine, but otherwise the water is safe to drink.
The announcement followed a site visit to the Lagoon Pond well Wednesday morning by water district officials with Terry Dayian, a representative from the Massachusetts Department of Environmental Protection Drinking Water Program.
On Monday the Lagoon Pond well was found to be contaminated by total coliform, a fecal indicator, after two consecutive tests were performed on water samples. The well is one of six wells that supplies water to the town.
Ms. Dayian examined the well site off Barnes Road for possible causes of the high bacteria count. She said the water level in the pond and surrounding wetlands was higher than she’d ever seen it, and suggested that the excessive rainfall compounded by the proximity of the well heads to that increased volume of standing water may have allowed bacteria to collect.
Possible solutions discussed included shutting down the well entirely, or isolating each well head and testing them individually to zero in on the bacteria source. Short -term, “shocking the system” with chlorine was also an option, Ms. Dayian said. A possible long-term solution would be to close the well during the spring and summer months, when rainfall is heaviest. The town could also decide to chlorinate the well system continuously, though this is an expensive alternative, Ms. Dayian said.
The DEP needed to confirm that there is enough water volume to supply the town without the use of the Lagoon Pond well.
The town continues to supply residents with bottled water at the library Tuesday, and is looking for ways to update the community on the status of the water situation, said town administrator Robert Whritenour.
The boil water announcement Monday prompted a run on bottled water by town residents and the town made the decision to hand out free water to people at the town library.
The water district has provided instructions for the safe use of town water following a boil order. Residents are instructed to run cold tap water until it feels cold, before using it to drink, brush teeth or use in cooking.