Residents returning home from work this evening along Roosevelt Drive between Lakeview Terrace and North Avenue should run their faucets for 15 minutes if they find their water smells of chlorine.
The tip comes after a much higher than normal chlorine concentration was detected in a pumping station on Roosevelt Drive that supplies drinking water to Derby residents Wednesday, according to the South Central Connecticut Regional Water Authority.
About 120 customers in Derby were affected, according to Tom Barger, Regional Water Authority’s manager of water quality.
The problem happened early Wednesday after a mechanical device that injects chlorine into drinking water as a disinfectant failed to shut off inside the pumping station.
The station then came online at about 6:45 a.m. and began pumping water into the distribution system, Barger said.
After about five minutes of pumping water, analyzers detected the higher-than-normal chlorine readings.
“As soon as the analyzers picked up that we elevated levels of chlorine, we shut the facility right back down again,” Barger said. ​“But there was about a five minute period that we were producing water.”
Barger did not have an estimate as to how many gallons of water was released into Derby.
He said acceptable chlorine concentration levels in drinking water ranges from one-to-two parts per million.
During the five-minute release, the chlorine levels within the pumping station were as high as eight parts per million, Barger said.
According to the Environmental Protection Agency, higher than normal concentrations of chlorine can cause irritation to the nose and eyes.
“Some people who drink water containing chlorine well in excess of the maximum residual disinfectant level could experience stomach discomfort,” according to the EPA.
The homes and businesses affected include the area between Lakeview Terrace to North Avenue along Roosevelt Drive and the homes along Park Avenue, Barger said.
Hawthorne Avenue, which runs parallel to Roosevelt Drive and Park Avenue, was not affected.
The homes in the area did not go without water, because the problematic pumping station was shut down and water was supplied from another Roosevelt Drive well field in Seymour.
Crews from Regional Water Authority flushed fire hydrants in the area for much of the day Wednesday.
“We’re trying to completely bleed out the system and get rid of all that water,” Barger said. ​“The well field is operating, but for waste only. We’re flushing out the distribution system and the well itself to make sure there are no residual issues. We’ll continue to do that into the evening as long as we need to.”
Crews have been monitoring the chlorine levels from the problem pump all day. It was still offline as of 4:45 p.m.
As of about 3 p.m., chlorine levels in water from fire hydrants on Park Avenue ranged from 1.28 parts per million to 1.43 parts per million, Barger said.
“What we’re looking at now is normal concentrations,” he said.
The water authority issued a statement to the media at 2:45 p.m. alerting the public to the incident.
“If you find the taste and odor intolerable, please use an alternate source of water, temporarily,” the statement read.
A CodeRED emergency notification went out to Regional Water customers at about 4 p.m.
Customers with questions were urged to call 203 – 562-4020.
As of 3 p.m., one customer in the affected area called the water authority to complain about a chlorine odor, Barger said.
