Rav Yosef Tzvi Rimon - Shabbat Bi-shabbato Haazinu
Question: Is one allowed to take a shower from water that was heated during the holiday in a solar heater?
Answer: In the Mishna there is a dispute between Beit Shamai and Beit Hillel whether one is allowed to heat up water on a holiday for the purposes of washing (Beitza 21b). The Shulchan Aruch follows Beit Hillel and rules that this is permitted. The accepted explanation for this is that the principle that some labors are permitted on a holiday for the purpose of providing "food for a person" is not limited strictly to food but includes other bodily pleasures, such as washing (Hilchot Yom Tov 1:16).
However, when washing the entire body is involved (as in a shower), there are two possible prohibitions:
(1) The prohibition to warm up water on a holiday. This appears explicitly in the Talmud (Shabbat 39b), and it is quoted in the Shulchan Aruch (511:1). The early commentators suggest two possible reasons for the prohibition. Tosafot explain that the permission to perform labor for "food for a person" (which is the basis for allowing water to be heated on a holiday) is only for a case which is equally available to everybody, and this corresponds only to washing separate parts of the body (Beitza 21b). They feel that heating up water in order to wash the entire body is a Torah violation. On the other hand, the Rambam (Hilchot Yom Tov 1:16) and the RIF (Beitza 11a) wrote that by Torah law the water can be heated, but that the prohibition to heat the water is a rabbinical decree.
(2) Washing using water that was heated before the holiday. This is the subject of a dispute of the early commentators. The Shulchan Aruch (511:2) rules following the RIF and the Rambam (quoted above), that this is not prohibited, while the RAMA prohibits it in the wake of the Tosafot (39b) and the ROSH (Mishna Shabbat 3:7).
In view of the above, there would seem to be a double problem in taking a shower on a holiday: a prohibition to heat up the water, and a prohibition to wash (for Ashkenazim).
In spite of this, in modern times we might still be able to allow taking a hot shower, for several reasons.
(1) Heating the water. Rabbi Akiva Eiger in a novel ruling writes that when the water is heated on Shabbat or on a holiday in a natural way, without any human action, it can be considered as having been heated up during the day, before the start of Shabbat or the holiday. This implies that it is possible to use water that was heated up in a solar heater during the holiday, as if it was heated the day before the holiday. This is also the opinion of Rabbi Shlomo Zalman Auerbach (Shemirat Shabbat K'Hilchata 14:3, and see note) and Rabbi Ovadia Yosef (Chazon Ovadia, Yom Tov, page 41). This then is a possible "solution" for the problem of heating the water.
(2) Using the water to wash. In light of what was quoted above from the Shulchan Aruch permitting the use of water that was warmed during the day before the holiday, the Sephardim have broad permission to take a shower using water from a solar heater. It would seem that this is forbidden for Ashkenazim, as indicated by the RAMA. This is indeed the ruling of prominent rabbis of the Ashkenazim, such as in Shemirat Shabbat K'Hilchata (14:7) and Rabbi Karlitz ("Chut Hashani," page 122), among others.
Evidently these rulings were correct in previous times, when it was quite rare for people to wash their entire bodies. But today when the norm (at least for our sector) is to take a shower every day, we can assume that the law has changed. There are two reasons for this.
1. In modern times, washing the entire body has the status of something that is "freely available to everybody"
The RAN (Beitza 11a in the RIF) explains that the prohibition of washing the entire body is not an independent law but is a rabbinical decree in order to avoid heating up the water on the holiday. This was copied from the laws of Shabbat, where there is a rabbinical decree not to wash the entire body in hot water even if the water was heated up before Shabbat, in order to avoid the prohibition of heating water. The RAN explains, based on this, that the prohibition of washing the entire body on a holiday is only relevant for those who feel that washing the entire body is a Torah violation (on a holiday as on Shabbat). In this way, he explains why the ROSH and the Tosafot prohibit washing, since they feel that heating enough water for the entire body is not freely available to everybody and is therefore a Torah violation, while the Rambam and the RIF, who feel that heating water is prohibited by a rabbinical decree, did not forbid washing.
According to the Tosafot and the ROSH, the prohibition of heating up water to wash the entire body stems from the fact that this act is not freely available to everybody. But today, when this has become a basic necessity for everybody, it is clear that they too would allow heating the water. If the reason that washing the entire body is forbidden is because of a fear of heating the water, then this prohibition is no longer valid. We can therefore state that Ashkenazim too are allowed to shower using water that was heated before the holiday (or using a solar heater on the holiday). This idea was brought as a suggestion in Shemirat Shabbat K'Hilchata (14, note 21), without a final ruling. However, according to Shulchan Shlomo (page 198) rabbi Shlomo Zalman Auerbach allowed a student of his to shower based on this type of reasoning.
(2) One who is "suffering."
Today, after a full day without a shower many people will feel a high degree of discomfort, which is defined in the halacha as "mitzta'eir" – suffering. This is certainly true of Rosh Hashana, a two-day holiday. The rabbis agree that the decree against washing the entire body is not relevant for a person who is "suffering" (Rabbi Akiva Eiger 326:1; Biur Halacha 326:1), out of a feeling that the rabbis did not put their decrees into effect in such a case.
In practice: In principle, one is allowed on a holiday to take a shower in the usual way, using water from a solar heater. One who would like to be stringent can use lukewarm water. Only liquid soap should be used, and it is important to avoid wringing out water and combing the hair.
