619. Wringing Out One’s Hair

86:3 One may immerse his entire body in cold water but he may not then stand in front of an oven to warm himself because this is like washing in hot water. Even if one only washed his hands in cold water, he may not warm them by the oven while they are still wet because this is like washing in water that was heated on Shabbos. Therefore, a person must be sure to dry himself thoroughly first. One should rub his hands together before wiping them on a towel so that there will only be a little water remaining on them. (Some authorities are lenient regarding holding wet hands near a fire to dry on Shabbos – see Mishnah Brurah 326:17.)
86:4 One who washes on Shabbos must be careful not to squeeze water from his hair. Similarly, he must not swim in the water because swimming is not permitted on Shabbos or yom tov. It is likewise prohibited to cause a piece of wood or other objects to float on a body of water. If one washed in a place where carrying on Shabbos is not allowed, he must be careful to remove the water from his hair and body before he gets out. He must dry himself carefully so that he will not end up carrying water from one domain to another. If one bathes in a river itself, he must also be careful not to carry water on his body more than four cubits (about six feet) because a river is a carmelis (the quasi-public domain). Because not everyone is proficient in these laws, the practice has evolved not to bathe on Shabbos at all, not even in cold water. The exception to this is for the purpose of a mitzvah, such as attending the mikvah. (Bi’ur Halacha 326:8 s.v. adam limits this to people who need to use the mikvah, not those who merely want to use the mikvah.)