The crustaceans are harmless, if a little gross, but removing them from the water is unfeasible and even detrimental. According to the Department of Environmental Protection, they provide "health benefits to water reservoirs." But copepods pose a unique religious problem for the city's 331,200 Orthodox Jews. Kosher guidelines prohibit shellfish consumption, and the discovery of the copepods ignited Talmudic debates over the water.
Only creatures visible to the naked eye are prohibited, but some copepods can grow up to 1.5 millimeters long and can be seen as little white dots flitting about in the water. So the Orthodox Union, the world's largest Kosher certification agency, released an official statement with guidelines on filtering water and washing dishes to avoid accidental contamination. There's no clear consensus on other potential offenses, like inadvertent consumption while showering or brushing your teeth, so to err on the side of caution, many of the city's Orthodox Jews have installed full house water filtration systems. Those things are pricey, but hey, if there's one thing worth filtering out, it's probably G-d's judgment.