Q: What is the meaning of "treatment" by which impure water becomes pure according to the jurists, and what is an example of it?

What is meant by treating impure water until it becomes pure, according to jurists, is that impure water is increased with pure water until the change (in its characteristics) disappears.

- Shafi'is and Hanbalis: If water reaches two qullas (a large quantity), it does not become impure unless its characteristics change. If it is less than two qullas, it becomes impure merely by the fall of an impurity into it. If water becomes impure (two qullas or more), its purification is achieved by the disappearance of the change in its characteristics, either by adding water to it or by the change disappearing on its own.

- Malikis and Hanafis: The purification of impure water by increasing its quantity, by pouring water onto it until the change disappears. The Malikis do not consider the two qullas measure, and water, in their view, does not become impure unless one of its characteristics changes. They dislike the use of a small quantity of impure water that has not changed if other water is available.