Immersing one's head in water
1618. If a fasting person intentionally immerses his entire head in the water, his fast is known to be void, even if the rest of his body remains out of water. But this act does not invalidate the fast; it is a Makrooh act, and as a measure of precaution, should be avoided.
1619. If a person immerses half of his head in the water once, and the other half the second time, his fast is not affected.
1620. If the entire head is immersed under the water, leaving some hair out, the rule applied will be that mentioned above in 1618.
1621. There is no harm in immersing one's head in liquids other than water like, in milk. Similarly, fast is not affected by immersing one's head in mixed water that is, Mudhaaf.
1622. If a fasting person falls into the water involuntarily, and his entire head goes into the water, or if he forgets that he is fasting and immerses his head in the water, his fast is not affected.
1623. If a person throws himself into the water thinking that his entire head will not go down into the water, and water covers his entire head, his fast remains in order.
1624. If a person forgets that he is fasting and immerses his head in the water, and he remembers under the water that he is fasting, it is better that he takes his head out of water at once, but if he does not do so, his fast will not be void.
1625. If a person is pushed into water and his head is immersed in water, the fast is not affected at all. But if the fellow who pushed him and forced his head under water releases him, it is better that he raises his head out of water immediately.
1626. If a fasting person immerses his head under water with the Niyyat of Ghusl, both his fast and Ghusl will be in order.
1627. If a person dives headlong in the water to save some one from drowning, although it may be obligatory to save that person, as a recommended precaution, he should give qadha for that fast.