Washing one’s body on Shabbat

Showering on Shabbat

1. Many water heaters or boilers are made so that automatically when hot water is removed cold water is added. If this is the case, it’s forbidden to remove hot water from the water heater, even if the water heater is turned off, because doing so will heat up the cold water which is added (which entails a violation of Bishul).

Washing one's hands

1. If one’s hands became soiled with mud one may not clean them off by wiping them on a towel or handkerchief however one may wipe them one a cloth which one isn’t concerned about cleaning (like a napkin).

Squeezing water from one's hair

1. It is forbidden to squeeze water out of one's hair on Shabbat. Similarly, one shouldn't shampoo one's hair on shabbat.
2. One may wet one's hair if one does not squeeze it out.
3. One should not shake one's head vigorously in order to remove the absorbed water.
4. One may tightly wrap a towel on one's hair to absorb the liquid because the liquid is absorbed immediately and becomes useless.