Second: when a person has water but needs it for drinking or cooking, and using it for purification would jeopardize that need to the point that he fears thirst for himself or for another respected human being or animal.

Third: when he fears that applying water will harm his body—by causing illness or delaying recovery—as indicated by Allah’s words, “If you are ill … then perform tayammum with clean earth” (Q 4:43).

Fourth: when illness renders him unable to move so that he cannot use water himself, no one is present to help him perform ablution, and he fears the prayer time will expire.

Fifth: when he fears harm from cold in using water and has nothing with which to warm it; then he performs tayammum and prays, for Allah says, “Do not kill yourselves” (Q 4:29). In all of these situations he may perform tayammum and pray.

If he finds water sufficient for only part of the required purification, he uses it on whatever limbs or parts of the body he can and performs tayammum for the rest, in accordance with, “So be mindful of Allah as much as you are able” (Q 64:16).

If he has a wound that would be harmed by washing or even wiping it with water, he performs tayammum for that limb and washes the remainder, again citing, “Do not kill yourselves” (Q 4:29).

If the wound would not be harmed by a light wipe, he wipes the bandage covering it with water, and that wiping suffices; no tayammum is then required.