Unfiltered Urban Water Supplies: Potential Religious Concerns Over Macroscopic Copepods Present in Drinking Water

Concern has arisen with various Orthodox Jewish communities as to the possibility that the specks that some congregation members are seeing in their household-drinking water might actually be invertebrates. The concern is because particles over 30 μm in diameter are considered by rabbinical law as visible to the naked eye. If crustaceans are present in the water and if they are in fact visible, they render the water un-Kosher, and therefore undrinkable and unfit for cooking. We were contacted by the Orthodox Jewish community of NYC about examining household drinking water for the presence of copepods to aid the rabbis in determining how best to advise their communities.A sampling device was attached to drinking-water taps in three of the major Orthodox communities of Brooklyn. The device was a 10 inch-long poly-bag filter housing with 10 μm nominal pore size nylon monofilament filter bags. Water, 100 gallons, was sampled at each site. Also, a half gallon of tap water was examined without magnification, and suspected copepods were examined with a dissecting microscope.In each sample copepod and cladoceran crustaceans were seen. The counts of microcrustaceans from each 100 gallons for the three houses in the different communities were 24,800, 15,480, and 18,780, respectively. In the examination of the half-gallon of drinking water, two specks resembled fairly large copepods. On the dissecting scope, the specks were identified as copepods. In only one case was a living microcrustacean observed; this was a developing cladoceran within the uterus of its dead mother.These organisms are not viewed as potential health threats; thus, their removal is not mandated by the usual laws that protect public safety. Killing of the organisms is not sufficient to render the water Kosher, because the presence of the bodies of the dead microcrustaceans is against rabbinical law. Because a large group of people are concerned for religious reasons about the presence of these organisms in their drinking water, it is important that communities understand the concerns of their constituents in the design of treatment facilities.