The Times tested water samples from 12 towers throughout Manhattan, Brooklyn, and Queens. In five tanks, the team found E. coli, which comes from the feces of animals like birds and squirrels. Those same tanks and three others also tested positive for coliform, a bacteria that is not harmful on its own, but thrives in conditions that are suitable for potentially dangerous bacteria, according to the report.
"According to state and federal standards," The Times wrote, "A positive result for either sample means that the water is not fit for human consumption."
The samples came from "muddy sediment" at the bottom of the tanks, which is below the pipe that feeds water from the tanks into the buildings. The city's health department says this sampling technique is not valid, but it's enough to raise red flags for at least one public health microbiologist. Stephen Edberg, of Yale University, told the Times: "The problem is that if any part of the tank gets contaminated, all of it is contaminated."
According to The Times, there are estimated 12,000 to 17,000 water towers in use in New York City. Although the city prides itself on having the highest-quality water in the world, supplied from upstate reservoirs hundreds of miles from the exhaust and grime of the Big Apple, The Times says that more than half of building owners do not ensure that their tanks meet health code regulations, which require that "tanks are cleaned, inspected and tested for bacteria every year."
The health department only recently mandated annual water tanks inspections, and that building owners make these test records available to tenants, according to The Times.