If a gentile heated water on Shabbos for an ill person, may someone else wash with that water?

            The Shulchan Aruch [1] teaches us that if a gentile cooked for a sick person on Shabbos, a healthy person may not partake of that food on Shabbos. [2] The reason is because Chazal were afraid that the gentile would purposely add food to the pot for the healthy person. [3]

The same reasoning is applied to our case. Were it permitted for a healthy person to bathe in hot water heated for a sick person there is fear that the gentile would heat water specifically for the healthy person. Accordingly a healthy person may not wash with that water.

            Is one permitted to take a cold shower on Shabbos?

            The abovementioned problems pertaining to hot water do not apply to bathing in cold water. However there are other problems. The Shulchan Aruch [4] teaches us that when one washes in a river on Shabbos, when coming out of the river one must take care to dry himself before walking four amos, because he will be ‘carrying’ the water in a carmelis. [5]

The Mishna Berura, quoting the poskim, says [6] that the custom is not to bathe in a river on Shabbos at all because of the various pitfalls involved with such bathing.

Just to mention two: carrying the water more than four amos on the river banks, and drying hair, which is a problem of squeezing. [7]

Many poskim are of the opinion that there is no difference between taking a cold shower and bathing in the river. Accordingly one must refrain from taking a cold shower or bath on Shabbos. [8]

HaRav Moshe Feinstein ztz”l writes [9] that although one ideally could make a distinction between a shower and bathing in the river, nevertheless one should not take a cold shower on Shabbos.

            Does that mean that there is no heter whatsoever to take a cold shower even when necessary?

            Rav Moshe writes that when necessary, such as during a heat wave etc. and one feels that a shower is of paramount importance, one may take a cold shower. [10] One should refer to a rav for guidance.

How is one to dry oneself after a cold shower?

            The main problem is squeezing water from wet hair. This is an issur d’rabanan [11] and therefore when drying a beard or drying hair on Shabbos, care must be taken not to squeeze water from the hair.

However, Rav Shlomo Zalman Auerbach writes [12] that when squeezed directly into a towel it is permitted, i.e. by placing the towel over one’s hair or beard and gently rubbing the hair into the towel, thus ensuring that the water is not squeezed onto the floor.

            May one use a sponge when washing oneself on Shabbos?

            Squeezing a sponge causes it to expel the water or liquid held within. Although squeezing falls under the umbrella of either Libun – laundering, or Dash – separating, in this case we are only concerned with separating. [13]

Many Rishonim are of the opinion that Dash is transgressed when one squeezes to expel the liquid. We must therefore examine this particular squeezing to see whether Dash applies or not.

The process of cleaning oneself with a sponge (or dishes for that matter) requires the area being cleaned to be wet. This is because sponging a dry area will obviously not have the same effect as sponging a wet one.

The advantage of using a sponge or cloth is that it continuously wets the area, which is brought about through squeezing the sponge or cloth during sponging. Consequently, the expelling of the water or liquid within is not merely a p’sik reisha (a by-product of the sponging) but a required part of the sponging.

Accordingly we would say that squeezing a wet sponge is ossur mid’oraisso.

            Does that mean that all sponges are prohibited?

            Basically yes. The only sponge permitted is the kind that does not hold water, such as the special type used to wash dishes on Shabbos. Since it is not practical to use such a sponge on one’s body, one should only use one’s hands without any sponge.

            Where else might we be concerned with this halacha?

            A very pertinent case involves cleaning an area prior to the insertion of a syringe. Before inserting a syringe it is necessary to disinfect the area with alcohol. This is usually done by soaking cotton wool in alcohol and rubbing it over the required area. Rav Shlomo Zalman Auerbach writes that this action involves Dash because one squeezes the alcohol from the cotton wool thereby wetting the area and enabling one to rub the area clean. [14] The alternative is to pour alcohol on the arm and rub it clean with a dry piece of cotton wool. The cotton wool should be precut before Shabbos or one should use tissues etc.