In the previous Halacha we have established that one may not wash one’s entire body or a majority of one’s body with hot water on Shabbat. It is likewise forbidden to wash one’s entire body with water heated before the onset of Shabbat or water heated by a solar water heater. The reason for this prohibition is based on a rabbinic enactment banning this, for when our Sages saw the bathhouse attendants transgressing prohibitions of Shabbat desecration in order to heat the water of the bathhouse, they prohibited bathing in hot water on Shabbat. Nevertheless, washing a minority of one’s body on Shabbat, such as one’s face, hands, and feet, is permissible provided that the water was heated in a permissible manner, such as before the onset of Shabbat or if it was heated by a solar water heater.
Regarding washing one’s entire body with cold water, according to Maran Rabbeinu Yosef Karo zt”l, there is no prohibition to do so as long as one is careful not to squeeze one’s wet hair or the towel which can sometimes constitute the prohibition of squeezing on Shabbat. Nevertheless, the Ashkenazi custom is to act stringently and to prohibit washing one’s body even with cold water on Shabbat because of the concern that this will result in the prohibition of squeezing on Shabbat among other reasons. However, in a situation of great discomfort or suffering, there is room for leniency even according to the Ashkenazi custom, for some say that the Sages did enact the prohibition of washing oneself on Shabbat in situations of great discomfort. Furthermore, others say that the Sages only enacted the prohibition of washing one’s body on Shabbat in bathhouses that existed in their times where people would immerse their entire body in a large vessel, or a ditch filled with water. However, regarding the bathrooms common in today’s households, especially since we do not immerse ourselves in the water and merely pour water on our bodies (by showering), there is no prohibition to do so. Thus, halachically speaking, there is room for leniency in situations of great discomfort even according to the Ashkenazi custom.
Although there is a prohibition to wash one’s entire body with hot water and this prohibition extends to washing one’s body with lukewarm water as well, nevertheless, during the winter when the water in the house is extremely cold, it is permissible to add some water heated before the onset of Shabbat or by means of a solar water heater to the cold water in a way that the heat of the water cannot be felt and only succeeds in making the cold water lose some of its chill. However, to bring the water to a point where it is lukewarm and then to wash one’s body with them is forbidden. (However, in the United States where the gas boiler is the common form of water heater as opposed to Israel where the solar heater is more common, it is prohibited to open the hot water faucet at all on Shabbat at all because of the prohibition of cooking the cold water which will immediately enter the tank as we shall discuss further in the following Halacha. The only permissible way to carry out the above idea is by using some hot water from a Shabbat urn or from a kettle on the Shabbat hotplate.) Regarding showering with hot water on Yom Tov, since this Halacha is not so pertinent at this time, let us just point out briefly that according to the rulings of Maran Rabbeinu Ovadia Yosef zt”l, one may wash one’s entire body with hot water on Yom Tov in one’s household shower provided that the water was not heated in a forbidden manner.
Nevertheless, we must point out that squeezing hair is forbidden on Shabbat (and Yom Tov). One must therefore take care not to rub in and lather the shampoo into one’s head on Shabbat as one usually would, for this constitutes the prohibition of squeezing the water out of one’s hair with the shampoo and transferring it to a different area of one’s head.
