JPress - an article by Dr. David Berger
Date: Wednesday, November 17 2004
A halachic ruling prohibiting New York City water was recently formulated by Rav Dovid Feinstein shlita and signed by Rav Yosef Shalom Elyashiv shlita and Rav Pinchas Sheinberg shlita. It affirms that once copepods can be seen as moving entities in the city's reservoirs, they remain prohibited even when they are not discernible in tap water.
Since water is so basic a substance, it is hardly necessary to point out the seriousness of this ruling. Even in an urban setting, it is easy to envision realistic scenarios involving jeopardy to the health of especially vulnerable observant Jews, not to speak of lesser but nonetheless deeply troubling consequences.
There are rabbinic decisors of stature who disagree with this stringent stance, relying on an attested and respected opinion recorded by earlier authorities that the water is permissible if the organisms in question are not discernible. (This is apart from the ruling by at least one distinguished rabbi that the copepods are permissible because of the halachic status of reservoirs.)
I make no pretenses to any standing in a debate among poskim on such a question, but I believe it is important to underscore certain considerations with the hope they will help encourage the latter authorities - while maintaining the highest reverence for the great rabbis who hold a stringent view - to keep the halachic discourse on this matter alive.
There is strong reason to believe that the presence of these crustaceans in the city water supply is not a new phenomenon - and that the almost universal, instinctive reaction that water imbibed over the years by a host of tzaddikim and talmidei chachamim must be permissible does not deserve to be dismissed as irrelevant.[...]