Amongst the number of recent eye opening events that have impacted the Jewish community, a discovery was made last May regarding the halachic status of New York tap water. The New York kosher consumer was shaken by the fact that New York tap water, which had the reputation of being one of the most pure, clean, and natural water available, contains unwelcome visitors called copepods that are visible to the human eye. In spite of that fact that this was a New York discovery, the Star-K hotline in Baltimore was abuzz with inquiries of “Can we drink the water?!” This is the Star-K response regarding copepods in drinking water based on discussions with Rav Moshe Heinemann Shlit”a, Star-K Rabbinical Administrator.

Q: What are copepods?

A: Copepods, also known as “insects of the sea,” are crustaceans that are found wherever water is found. The typical length of an adult copepod is 1-2 millimeters but some species can be as small as .2 millimeters. They are an important link in the ecosystem because copepods consume mosquito larvae that carry malaria. However, copepods are not kosher. If they can be seen by the naked eye, they may not be eaten and one should not drink water containing these uninvited guests.

Q: How large does an insect have to be in order to be considered visible?

A: Insects that are too small to be seen by the naked eye are not forbidden. If one requires a magnifying glass or a microscope to see an insect, then the insect is considered too small to be seen. However, if one sees white lint floating in the water and it is not recognizable as an insect, but through magnification one realizes that the white lint is indeed a copepod, the copepod is considered visible according to some opinions. Therefore, the water should not be consumed.

Q: What is a practical solution to resolve this problem?

A: The water should be filtered. The water filter can be connected to the faucet or to the home water source.

Q: Can this filter be used on Shabbos?

A: Water used for drinking should be filtered before Shabbos. Water used for washing dishes can be filtered on Shabbos.

Q: Does Maryland water have this problem?

A: No, Maryland water is filtered at the water treatment plant. New York water is not filtered. See diagram below.