It is forbidden to wash one's whole body
or even most of one's body in hot water,
even if (the water) was heated up before Shabbat started,1
and even to wash not at one time,
but limb by limb, is forbidden for most of one's body.
Even to go into a bathhouse just to sweat is also forbidden.
However it is allowed to wash one's face, hands, and feet2
from hot water that was heated before Shabbat.31) Originally, bathing in hot water heated before Shabbat was allowed. However, the Sages discovered that many bathhouse owners were heating up water on Shabbat itself, and claiming that they heated it up before Shabbat. In response to this, the Sages prohibited bathing but still allowed entering the bathhouse on Shabbat for the purpose of sweating. They then discovered that people were entering bathhouses to bathe in hot water, and then claiming that they only entered to sweat. Consequently, the Sages prohibited entering the bathhouse even for sweating purposes (Shabbat 40).
2) Or any other part of the body, as long as one doesn't wash the majority of one's body.
3) According to the Mishna Berurah in his Biur Halachah (326:1), if one is experiencing great discomfort, one may bathe in hot water which was heated before Shabbat. Others disagree.
אסור לרחוץ כל גופו
או אפילו רוב גופו במים חמים
אפילו הוחמו בערב שבת
ואפילו לרחוץ שלא בפעם אחת
אלא אבר אבר אסור ברוב גופו
ואפילו ליכנס למרחץ רק להזיע גם כן אסור
אבל מותר לרחוץ פניו ידיו ורגליו
מחמין שהוחמו בערב שבת Hot water that is from hot springs such as the Tiberias springs and similar,
if they are (in a pool) in the ground and the place is not covered by a roof,
it is allowed to wash in them even one's whole body,1
but if they are in a container2 or the place has a roof3 it is forbidden.
Even to go in to the bathhouse only to sweat is forbidden.
Some (authorities) say that as long as they are (in a pool) on the ground,
even if the place has a roof, it is permitted to wash in them.41) Only water heated by fire is prohibited on Shabbat.
2) People may mistakenly assume that the water in the container was heated by fire, and conclude that it is permitted to bathe on Shabbat in water heated by fire.
3) A roofed room could be used for sweating, which, as mentioned above, is also rabbinically prohibited on Shabbat, even if the source of the heat is a natural hot spring; consequently, the sages prohibited bathing in a roofed hot spring.
4) According to this lenient opinion, the sages only prohibited sweating in places where it would be prohibited to bathe. Therefore, it would be permitted to bathe in a hot spring situated in a roofed room. The Mishna Berurah (326:11) rules that one may rely on this opinion.
המים שהם ממקורם נובעים חמים כמו חמי טבריא וכדומה
אם הם בקרקע ואין המקום מקורה
מותר לרחוץ בהם אפילו כל גופו
אבל אם הם בכלי או שהמקום מקורה אסור
ואפילו לכנוס רק לבית המרחץ להזיע אסור
ויש אומרים דכל שהם בקרקע
אפילו המקום מקורה מותר לרחוץ בהם It is allowed to immerse one's whole body in cold water.1
However one should not stand afterwards in front of an oven to warm oneself,2
because this is like washing in hot water.
Even if one washed only one's hands in cold water,
one shouldn't warm them by the oven while they are still wet,
since this is like one who washed in water that was heated on the (Shabbat) day,
with which it is forbidden to wash them, even one limb,3
rather one needs to thoroughly dry them first.
See further in Chapter 80, Law 32,
that one should rub them (together) before wiping
so that there will only be a little water left on them.41) The prohibition against bathing one's whole body in water heated before Shabbat, only applies if the water is considered hot (that is, people would call it ''hot water'' - see Aruch Hashulchan 326:3). It is allowed to bathe one's whole body in luke warm water (as long as it was heated before Shabbat) and therefore, one may immerse in a luke warm mikvah on Shabbat (Mishna Berurah 326:7); some authorities even allow using a hot mikvah.
2) Before drying off.
3) Other authorities rule that one may place wet hands next to a fire to dry on Shabbat, because the water is only really becoming warm, not hot, and hence it is equivalent to water which was heated before Shabbat, with which it is allowed to wash individual limbs (Mishna Berurah 326:17).
4) In certain circumstances, making a towel wet on Shabbat is prohibited, because it is considered part of the laundering process.
מותר לטבול כל גופו בצונן
אבל לא יעמוד אחר כך נגד התנור להתחמם
משום דהוי כרוחץ בחמין
ואפילו רחץ רק ידיו במים צוננים
לא יחמם אצל התנור בעודם לחים
משום דהוי כרוחץ במים שהוחמו היום
דאסור לרחוץ בהם אפילו אבר אחד
אלא צריך לנגבם תחלה יפה
ועיין לעיל סימן פ' סעיף ל''ב
שישפשפם קודם הניגוב
שלא ישאר עליהם רק מעט מים One who washes (on Shabbat) needs to take care not to squeeze (water from) one's hair.1
Similarly, one should be careful not to swim,
because it is forbidden to swim on Shabbat or a festival.2
It is also forbidden to float an object, such as a piece of wood on the water.3
If one washed in a place where it is forbidden to carry,
one must be further careful and before getting out
one first removes the water that is on one's body and hair,
drying them carefully so no water remains on them
to be carried into the public domain.
Also in the river itself one needs to be careful
not to carry (on one's body) the water more than four cubits,
because the river is a semi-public domain.4
Because not everyone knows to be careful
it has become customary in these countries
not to wash at all (the whole body) on Shabbat even in cold water,5
except for the purpose of a comandment,
e.g.; a woman after her period as explained in Chapter 162, Law 7,
or a man after a seminal emission.71) It is Biblically prohibited to wring liquid from an absorbent fabric, because it is part of the process of laundering. The Rabbis extended this prohibition even to non-absorbent fabric that traps water between its fibres, and to hair. See Chapter 80 Laws 33-37.
2) This is a rabbinical prohibition (See Shulchan Aruch 339:1).
3) For example, it is prohibited to push the pieces aside in the water, in order to clear the area of water one is standing in. This prohibition applies only in a river, lake or ocean, not in a tub or pool.
4) A ''carmelit'' where it is forbidden to carry. Some argue that while in the river itself, the water on one's body is considered to be connected to the water in the river, and thus it would not be considered carrying.
5) In other words, due to the various prohibitions that one may come to violate while bathing, it became customary not to bathe one's whole body, even in cold water, on Shabbat.
6) It is allowed to immerse in a ritual pool on Friday evening. This requires washing the body first.
7) Many men have the custom of immersing in a ritual pool after a seminal emission.
הרוחץ צריך ליזהר שלא לסחוט שערו
וכן צריך ליזהר שלא לשוט
כי אסור לשוט בשבת וביום טוב
וכן אסור להשיט איזה דבר כגון הקיסמין שעל פני המים
ואם רוחץ במקום שאסורין לטלטל
צריך עוד ליזהר שקודם צאתו
יסיר תחלה המים שעל גופו ושערותיו
לנגבם יפה שלא ישאר עליו מים
ויוציאם מרשות לרשות
וגם בנהר עצמו צריך ליזהר
שלא ישא את המים שעליו ארבע אמות
כי הנהר הוא כרמלית
ולפי שאין כולם יודעים ליזהר
על כן נתפשט המנהג במדינות אלו
שלא לרחוץ כלל בשבת אפילו בצונן
כי אם לצורך מצוה
כגון אשה נדה כדלקמן סימן קס''ב סעיף ז'
ואיש לקריו It's permitted to stand on a river bank (on Shabbat) and wash one's hands in the river,
and it is not prohibited
that one carries water on one's hands from the river to the bank,
because the river is a semi-public domain
and the river bank is also a semi-public domain,
and it is permitted to take out of one semi-public domain
to (another) semi-public domain less than four cubits,
only one needs to be careful to dry one's hands carefully before walking four cubits. מותר לעמוד על שפת הנהר ולרחוץ ידיו בנהר
ואין זה איסור
במה שהוא מוציא את המים שעל ידיו מן הנהר על שפתו
לפי שהנהר הוא כרמלית
ושפת הנהר הוא גם כן כרמלית
ומותר להוציא מכרמלית
לכרמלית בפחות מארבע אמות
רק שיזהר לנגב ידיו היטב קודם שילך ארבע אמות One may rub one's hands1 with crushed grain even though the hands are wet,
as long as one doesn't put the water onto the crushed grain itself,2
however it is forbidden to rub one's hands with salt
and certainly (not) with soap.3
because it softens.1) To clean them.
2) One of the prohibited activities on Shabbat is kneading, that is, mixing flour and water to make dough. Performing work in an unusual way, is not considered a biblical violation, but it is rabbinically prohibited, except in rare circumstances. However, when using crushed grain to clean one's hands, not only is the ''kneading'' (mixing the grain and the water on one's hands) being performed in an unusual way, but also, one doesn't intend to knead, and, according to many authorities, a biblical act of kneading cannot even be achieved using crushed grain (See Aruch Hashulchan 326:11)
3) In many circumstances, it is rabbinically prohibited to actively turn a solid into a liquid on Shabbat, because it is as if one has created a new entity; this prohibition is called ''Nolad'' - new-born. Using a solid bar of soap involves the additional problem of performing the activity of ''smoothing'', which entails rubbing or spreading a substance to give it a smooth surface. According to most authorities, it is allowed to use liquid soap on Shabbat, because its fluid consistency exempts it from the prohibition of ''smoothing''.
מותר לשוף ידיו במורסן אף על פי שהידים רטובות
ובלבד שלא יתן את המים על המורסן ממש
אבל אסור לשוף ידיו במלח
וכל שכן בבורית, סבון
משום דנימוח Waters, which are not normal to wash in,
rather to use for medical purposes, e.g.; noxious or foul water,
are forbidden to wash in them on Shabbat,
because it's obvious it's for medical reasons.1
When does this apply ? When one stays in there.2
If one doesn't stay in there,
it is permitted, for it appears just for cooling off.3
In hot springs like those of Tiberias,
where one bathes in them only for medical reasons,
it is forbidden to wash in them on Shabbat for medical reasons,
even when one does not stay in there.41) The Sages prohibited doing anything for healing purposes on Shabbat, except where absolutely essential, because they were concerned that one may come to grind substances for use as medicine; ''grinding'' being one of the 39 prohibited Shabbat activities (see Chapter 80, Law 15).
2) If one stays, it is obvious that one is bathing for medical purposes, otherwise one would not remain in disgusting water for more than a short time.
3) People could assume that the person was unable to find cleaner waters in which to cool off. Remaining in this type of water for a short time is permissible even if one's intent is for healing purposes, as long as it is not obvious to onlookers that this is the intent.
4) Obviously, in the case of hot springs, onlookers can't assume that the person is cooling off, and thus, even immersing for a short time is prohibited. However, according to the Mishna Berurah 328:137, immersing in hot springs for a short time is permissible. Also, the prohibition only applies to someone who is bathing in these springs to alleviate slight discomfort, however, when one is actually ill, it is permissible to bathe in them.
מים שאין הדרך לרחוץ בהם
אלא לרפואה כגון שהם רעים או מאוסים
אסור לרחוץ בהם בשבת
כיון שניכר שהוא מכוין לרפואה
במה דברים אמורים כששוהה בהם
אבל אם אינו שוהה בהם
מותר שאינו נראה אלא כמיקר
ובחמי טבריא וכדומה
אם אין הדרך לרחוץ בהם אלא לרפואה
אסור לרחוץ בהם בשבת לרפואה
אפילו אינו שוהה בהם