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11 Tishrei 5766 - October 15, 2005 | Mordecai Plaut, director Published Weekly










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Israeli Water is Bug-Free

by Rav Moshe Vaie

author of Bedikas Hamozone Cehalocho

Translated from Volume 3 of Bedikas Hamozone Cehalocho (now being prepared for publication in Hebrew)

Summer 5764 (2004)

A Jew residing in New York bought Chasalat-brand lettuce from Eretz Yisroel and, following the instructions, washed the leaves well. As an extra precaution, after washing them he held the leaves up to the light by a window to examine them and saw that small insects remained on the leaves. He washed them again, and again found the same phenomenon — and even after a third washing.

He complained to the company that grows the vegetables and included a sample of the insects that he found on the lettuce. However, the expert who examined the sample found that they were not insects that are found on lettuce, but small creatures found in water!

"If that's the case," said the man from New York, "let's check the water."

His quick investigation revealed a shocking finding: In the tap water were little "pieces of dirt" that were actually tiny crabs! Checking by his neighbors and in other neighborhoods, he found similar results: in New York tap water there are tiny creatures — known as "zooplankton."

The problem is specifically in New York City drinking water, which is considered [by the US health authorities] to be of particularly high quality, since it comes directly from the Catskill Mountains. In other American cities there is a law requiring that the water must be filtered before being distributed to consumers, but in New York City, because the water is of such high quality, the authorities do not filter it and it is sent directly from the reservoirs to the consumer. The longer the water stands in the reservoir, the higher is the level of infestation.

When the first reports came in from New York, a red light went on by us. What about our water in Eretz Yisroel?

A preliminary investigation revealed that the water in Israel is not filtered either. Here too, most of the water sent to homes is standing water whose source is the Kinneret, in which the same creatures are found.

As a result, we launched a broad investigation into the presence of insects in drinking water in Israel, New York, and other places. The results follow.

Halachic Perspective

The gemora in Chulin (66:2) teaches that worms found in cisterns are not included in the prohibition of insects, and the Shulchan Oruch (Yoreh Deah 84:1) rules accordingly (on the condition that the water is drunk directly from the cistern and is not drawn in a vessel). However, this law applies only to water in a closed cistern where there is no flow of water. In systems where the water flows, the insects in the water are prohibited.

When, in 2004, it was discovered that in New York City drinking water there are clearly visible creatures (their size is 1 mm.) HaRav Y. S. Eliashiv, HaRav Chaim P. Scheinberg, HaRav Dovid Feinstein, and other important rabbonim ruled that these insects are prohibited, since the reservoirs are fed from flowing water.

Therefore G-d-fearing Jews in those areas installed filters on their sinks in order not to transgress the prohibition of eating insects.

Drinking Water in Eretz Yisroel

Water Sources

In standing water such as ponds, cisterns, reservoirs, and water tanks, zooplankton, which are tiny creatures ranging in size from 0.1 to 1.0 millimeters, are found. In the Kinneret for example, hundreds of creatures can be found in each liter of water. They are usually transparent-to-white and can be seen easily, even without magnification: Fill a clear glass or bottle with Kinneret water and look at it against the light or on a dark surface (such as a black piece of material or paper). Small creatures can be seen floating in the water.

In underground water such as aquifers, the water is usually free of living creatures.

Most of the homes in Israel get their drinking water from the Kinneret. A minority gets water from aquifers. In Jerusalem, however, most of the water comes from aquifers and only 20-40 percent comes from the Kinneret.

Water from the Kinneret is transported to settlements throughout the country, from the north to the south. The water is transported from the Kinneret via the National Water Carrier in open canals until the Eshkol Reservoir. In addition to the zooplankton found in the waters of the Kinneret, in the reservoir tiny algae, snails, nematodes, and other creatures develop.

Cleaning Methods

In the reservoir, the water undergoes various cleaning processes:

Physiochemical processing - Sedimentation. An alum sulphate solution is introduced into the water which causes substances floating in the water to sink to the bottom of the reservoir.

Biological processing. Scavenging fish found in the water, such as carp, silver carp, and St. Peter's fish, eat the algae and the creatures in the water.

Chemical processing. Before the water leaves the reservoir (to the pipes that take it eventually to the homes), chlorine compounds are introduced into it. The purpose of these substances is to kill and destroy living creatures remaining in the water.

Filtering. An advanced filtering system for the National Carrier is in the final stages of development and installation. The system is composed of huge sand filters which draw out the various particles. Then the water passes through charcoal filters which neutralize the chlorine taste of the water. This system is scheduled to begin functioning in September 2006.

After the first three processes, the water reaches a level of purity of 1 NTU (as compared to the founding period of the National Water Carrier about forty years ago, when the standard was 25 NTU). After the filtering system begins working, it is hoped that a level of 0.5 NTU will be achieved. This is one of the highest levels of water purity in the world.

It should be noted that the NTU standard refers to the general purity of the water and not specifically to living creatures.

When the water leaves the reservoir, it is 99 percent clean of living creatures. In other words, it contains an average of 2 tiny creatures in a liter of water. These creatures are very tiny and they die and are partially crushed as a result of the chlorine.

Drinking Water in Eretz Yisroel

The water is transported from the reservoir to the various cities and towns by an underground piping system that is altogether 86 kilometers long. In dark, closed places like pipes, zooplankton do not develop.

The few creatures that remain after the reservoir are apparently crushed in the pipes and are not found in the drinking water.

In 5765 we carried out a study under the auspices of the Institute for Jewish Heritage, in which we studied over 100 samples of water from various settlements in Eretz Yisroel [Amuka, Atlit, Ashdod, Ashkelon, Beer Sheva, Beit She'an, Beit Shemesh (several locations), Beitar, Bnei Brak (several locations), Carmiel, Gush Katif, Haifa, Jerusalem (tens of samples from various neighborhoods), Kinar, Modiin Illit (several locations), Netanya, Netivot, Ofakim, Rechasim, Tveria, Tzefat, and more]. All the samples were found to be clean, without infestation by living creatures.

Each check involved the filtering of tens of liters of tap water.

In summary, the tap water in Eretz Yisroel appears to be clean, and there is no need to filter it.

Drinking Water in New York City

In most of the United States the law requires filtering of the water before it is supplied to the consumer. However, in New York City (as well as in Boston and Seattle, that we know of) the water is considered very high quality, and is not filtered.

Although the New York water undergoes similar processes to those undergone by the Kinneret water, an average of ten zooplankton are found in each liter of water. The water is chlorinated and this causes the creatures to die and become partially crushed, but they are easily visible in the water. Although to the untrained eye they look like little pieces of dirt, if they are examined carefully or magnified 10 times it can readily be seen that they are water creatures. Therefore tap water in New York City must be filtered.

The recommended method for filtering is to use a tightly woven cloth, preferably doubled, since the force of the water may push the insects between the threads of the cloth. The cloth should be replaced or laundered frequently.

Alternately, a commercial filter with holes no bigger than 50 microns, which is installed over the tap, is recommended.

If a central filter for the entire water system of a house, factory, or restaurant is used, one should use a filter from a well-known company, which conforms to approved standards.

The filter should be cleaned and maintained according to the manufacturer's instructions.

Boiling the water does not destroy the insects.

Drinking Water in Other Countries

We do not have clear information on the state of the water in other countries, and it is recommended that the water be checked.

The recommended method for checking is as follows. Cover the spigot with a tightly woven cloth, and after several days of use (preferably a week) remove the cloth carefully and place it in a transparent vessel of water, such as a glass, with the inner side of the cloth facing the bottom of the glass, deep in the water. Shake the cloth gently in the water. Remove the cloth and check the water over a dark background (e.g. a black cloth or paper). If small white "pieces of dirt" are found, examine these with a 10x magnification magnifying glass.

Reserve Water Tanks

Some people in Israel have a water tank on the roof, for example for Shabbos use. These tanks must be tightly covered and must be cleaned and disinfected at least once a year. Instructions for proper maintenance of reserve water tanks are available from the Gichon Agency in Jerusalem.


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