Insufficient chlorine in Pittsburgh's public water supply led to the closure Wednesday of nearly two dozen grade schools and a boil-water advisory in neighborhoods that include the University of Pittsburgh and Carnegie Mellon University.
The Pittsburgh Water and Sewer Authority said the advisory applied to 100,000 customers in the city of more than 305,000 residents, but officials also stressed that the advisory was only a precautionary measure and no public health problems have been reported.
Tests by the Pennsylvania Department of Environmental Protection showed low levels of chlorine in water at a plant that draws water from the city's Highland Park reservoirs. Without enough chlorine, a parasite known as giardia can grow and cause severe diarrhea in those who drink the water, officials said.
Authority director Bernard Lindstrom said late Tuesday, "There is a minuscule risk of having any bacteria in our water system and we have not detected any bacteria in our water system at all." He said the advisory "is a very precautionary measure we are taking. We do not think there is any undue risk to water safety or public health at this time."
Mayor Bill Peduto said the parasite typically takes seven to 10 days to incubate and officials had no evidence the bacteria was in the water.
Crews worked Wednesday to isolate the reservoirs from the rest of the city's water supply, while the city set up water distribution points at 11 fire stations where residents could get bottled water or fill jugs from metal water buffaloes. The boil-water advisory will be lifted, once chlorine levels are safe.
The city's central and eastern neighborhoods were affected by the advisory. That area includes Oakland, the neighborhood where the University of Pittsburgh and Carnegie Mellon University are located. The schools were complying with the advisory, but didn't cancel classes or activities.
Pittsburgh Public Schools closed 22 schools. Two early childhood centers also were closed. But officials said they were hopeful the schools would reopen Thursday.
The University of Pittsburgh Medical Center said its hospitals were operating normally and not canceling any surgeries or other procedures Wednesday. UPMC was providing bottled water to its patients and otherwise abiding by the boil-water advisory.