Tiny Crustaceans in the Water Supply
In the spring of 2004, rabbis in Brooklyn noticed small white specks
in the tap water.
These were copepods, tiny animals.
New York City gets its drinking water from a clean natural source
well outside the city.
It one of the few cities in the U.S. that are exempt from federal
requirements for filtering their drinking water.
The other such cities, however, including Seattle, Boston, and
San Francisco, don't have large populations of Orthodox Jews.
The copepods are tiny, but theologically significant.
Copepods are crustaceans, a large and diverse group that includes
crabs, lobsters, and shrimp.
That makes them forbidden.
or the dietary laws, prohibit sea creatures without fins or scales.
The basics of kashrut come from the Torah's books of
Leviticus and Deuteronomy.
The details, however, of just what makes something
or kosher come down from oral tradition.
Details are written down in the Mishnah and Talmud,
and further discussed and argued in later rabbinical literature.
And, details are always subject to further argument and discussion.
Creatures too small to see don't matter.
Some copepods are as small as 0.1 mm.
Others, however, may be as long as 1 to 2 mm,
and therefore visible as small white specks floating
in a glass.
Copepods inhabit almost every freshwater and saltwater habitat.
There are some 13,000 species, 2,800 of which live in fresh water.
They have an armored exoskeleton, but most are so small that their
thin armor and entire body are almost entirely transparent.
Most have a single compound eye, usually red and at the center
of the transparent head.
They so small that they need no heart, circulatory system, or gills,
simply absorbing oxygen directly into and through their bodies.
Kunstformen der Natur
contains a colorful plate of copepods showing their
wide variety of appearances under the microscope.
Latrines and Lübeck: Toilets Reveal Hanseatic History
Copepods featured in the study of cesspit contents that revealed
economic trends in the medieval
Copepods can function as an intermediate host
in the complex life cycle of parasitic worms.
But that's only when they ingest worm eggs in human feces
contaminating freshwater streams and ponds.
New York City's Water Supply
New York's water supply comes from the Catskill Mountains,
where the water is only lightly contaminated if at all.
It's drawn from about 60 feet below the reservoir's surface
and well above its bottom.
Chlorine and fluoride are added, and it's piped to the city and distributed.
The High Bridge carrying the Croton Aqueduct over the Harlem River from
the Bronx to Manhattan.
So, the copepods in the New York City water supply aren't medically
But they aren't kosher.
Or at least when they were first noticed,
there was worry that they rendered the city tap water non-kosher.
A copepod of the Corycaeus genera which, unusually, has two eyes.
How to Make the Water Kosher?
Plumbers were commissioned to install water filters.
Some whole-house water filtration systems cost as much as $1,500 installed.
Others were only $99.
Several restaurants posted signs in their windows announcing
that they filtered their water.
The Orthodox Union published a
describing what was known at the time.
Meanwhile, rabbinical authorities launched a Talmudic analysis
of very fine details.
Would it be permissible to use unfiltered water to cook?
To wash dishes?
To brush your teeth?
Would filtering water on the Sabbath violate other prohibitions?
The city was in the process of installing filters at the Croton reservoir,
a project that would cost about $1 billion and take six years to complete.
What to do in the meantime?
This Croton Aqueduct manhole cover in Jersey Street,
a block south of Houston in Manhattan,
is said to date from 1866 and to be the oldest manhole cover in New York City.
A group of rabbis traveled to the reservoirs and asked detailed questions
about the water supply and the copepods.
Eventually, in August 2004, the Orthodox Union ruled that the water
was kosher, copepods and all.
They recommended that restaurants and caterers under their jurisdiction
filter their water, but it wasn't necessary for homes.
They tried to be as practical as you can in a Talmudic debate over
It is acceptable to wash dishes by hand in unfiltered water,
if the dishes are towel-dried or stood on edge in racks
to air-dry without holding puddles of waters.
They also said that water should not be filtered on the Sabbath.
There are 39 forms of work forbidden on the Sabbath,
and one of these is "selection" or sifting of food,
like separating wheat from the chaff.
Or, they concluded, copepods from the water.
David Berger, a professor of history at City University Graduate Center
and a rabbi, said: "The notion that God would have forbidden something
that no one could know about for thousands of years, thus causing
wholesale, unavoidable violation of the Torah, offends our deepest
instincts about the character of both the Law and its Author."
Rabbi Moshe Dovid Tendler, who is a professor of both biology and
Talmudic law at Yeshiva University, said that he only noticed copepods
in tap water after he had used a 60-power dissecting microscope
to examine them in the lab.
He said: "The hidden things belong to God, we are responsible for
what we see.
If you don't know about it, and don't see it, then it doesn't exist.
So those who drank the water before were drinking kosher water."
So, drink up.
The water, and the copepods, are kosher.