There is no harm in performing ablution, washing after major impurity (ghusl), or using rose water for cleansing. However, do not use water heated by the sun for ablution, washing after major impurity, or kneading dough, as it is said to cause leprosy. There is no harm in performing ablution with hot water. Water is only corrupted (rendered impure) by substances that have a flowing soul (i.e., those that bleed). Any object that falls into water and does not have blood may still be used for ablution and other uses, regardless of whether it died in the water or not. If you have two containers and something that makes water impure falls into one of them, but you do not know which, pour out both and perform tayammum (dry ablution). If water from two drainpipes flows down, one with urine and the other with pure water, and they mix and get on your clothes, there is no harm.