"When the results of tests for lead in the water at more than 1,500 New York City school buildings were announced in July, officials said that fewer than 1 percent of all the samples taken showed lead concentrations that exceeded Environmental Protection Agency guidelines. Given other safety measures in place, officials assured parents, the water was safe to drink.

But a review of how the testing was conducted suggests that the amount of lead in the water that students consume could be greater than the results indicate.

According to the city, every water outlet in each school was turned on fully for two hours the night before the samples were taken — a practice known as pre-stagnation flushing that cleans most soluble lead and lead particles from pipes and thus reduces lead levels temporarily."

Kate Taylor reports for the New York Times August 31, 2016. [2]