Chapter 86:4
Bathing on Shabbos
4. A person who bathes on Shabbos must be careful not to squeeze water
from his hair (1). Similarly, he should be careful not to swim, since it
is forbidden to swim on Shabbos or on a festival (2). Similarly, it is
forbidden to cause anything else to float through the water, such as pieces
of wood (3).
When bathing in a place where it is forbidden to carry on Shabbos, one must
take a further precaution: before leaving the body of water, one should
remove all the water from his body and hair, drying them thoroughly so that
no water remains on his body to be transported from one domain to
another. Furthermore, one must take care not to carry water (on one's
body) more than four amos within the river itself, because a river is
considered a "carmelis" [in which it is forbidden to carry] (4). For these
reasons, it has become customary in these countries not to bathe (one's
whole body) on Shabbos even in cold water (5), except for purposes
associated with a mitzvah, for example, a woman in preparation for a
"hefsek taharah" (6) (see Chapter 162, Law 7), or a man after a seminal
emission (7).
FOOTNOTES:
(1) As we saw in Halacha Yomi 80:33-37, it is Biblically prohibited to
wring liquid from an absorbent fabric, because it is part of the process of
laundering ("Kibus"). The Rabbis extended this prohibition even to
non-absorbent fabric that traps water between its fibres, and to hair.
(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) 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 Shabbos.
(6) This required washing the genital area.
(7) Many men have the custom of immersing in a mikvah after a seminal emission.
