Westerly Water Department customers who have not used their water since Friday are being warned to flush their systems before drinking or using the water because of the chemical problem that was detected late Thursday and into Friday.
The warning was issued at about 5:30 p.m. Tuesday by the Rhode Island Department of Health, and by the water department at about 7 p.m.
The warning advises customers whose system has been stagnant since Friday to perform a one-time flush of household faucets for 3 to 5 minutes to discharge water with potentially high concentrations of chemicals.
Faucets that have been in regular use since Friday have already been flushed of these chemicals, the water department said. The recommended flushing is intended to address the possibility of a high level of potassium hydroxide, a chemical used to raise the pH level of the water to make it less corrosive. A mechanical malfunction at a pumping station caused a higher than intended level of the chemical to build up and become injected into the system.
Exposure to very high pH values, according to the warning, can result in irritation to the eyes, skin, lips, mouth, nasal passages, and other mucous membranes. In sensitive individuals, gastrointestinal irritation may also occur.
On Friday evening a Pawcatuck household reported that a father and his teenage daughter experienced skin irritation after showering. Tests of the water at the residence detected a pH level over desired ranges. The residential system and pipes in the neighborhood were flushed. No other problems were reported, according to Paul Corina, Westerly Public Works director. The system around the pumping station where the problem originated had been flushed earlier in the day following discovery of the mechanical malfunction.
Corina said he notified the Rhode Island Department of Health of what occurred on Tuesday, after speaking with Connecticut Department of Public Health officials, and was told that a warning should have been issued earlier. Unlike situations in which water is contaminated by bacteria, Corina said state guidelines are unclear about notification requirements for pH problems.
According to the Westerly Water Department warning, there is no health-based guideline for pH in drinking water. The system typically operates at a pH of around 7-8. On Thursday night and Friday some sections of the system may have experienced pH levels above 10 because of the malfunction in treatment equipment, according to the warning.
The warning was posted on the Westerly municipal website and sent by e-mail to those who have signed up for electronic bulletins from the town. An automated phone call to subscribers was also made by the town. The warning was provided to officials in Stonington who also made an automated phone call to subscribers. Ledge Light Health District, which functions as Stonington’s health department was also informed of the warning, Corina said.