become impure. Human urine and excrement are excluded from this, as previously stated.

The correct view is that this does not render it impure unless it undergoes a change.

According to the madhhab, an exception is made when it comes into contact with the impurity at the site being cleansed, for then it does not become impure (1). For example, if a person has some impurity on his garment and wishes to remove it, he pours over it a small amount of water—less than two qullahs. If we were to say that the water becomes impure merely by coming into contact with the impurity at its location, namely the garment, it would be impossible to purify this impurity, because once water becomes impure through contact, it cannot purify the impurity. The same would apply if he poured another amount of water over it. For this reason, they made an exception in this case.

Or if it separates from the site of an impurity before its ruling has ceased. If a large quantity of tahur water—other than earth and the like—is added to impure water, ............

His statement, “Or if it separates from the site of an impurity before its ruling has ceased,” means: before its legal ruling has ceased.

For example, water used to cleanse an impure garment: the impurity may be removed in the first washing, and its trace may disappear completely in the second. Yet if we wash it a third, fourth, fifth, and sixth time, the water that separates from these washings is impure, because it separated from the site of the impurity before its legal ruling had ceased.

His statement, “If a large quantity of tahur water—other than earth and the like—is added to impure water,” explains the methods by which impure water may be purified. He mentioned three methods for purifying impure water:

The first is to add to it a large quantity of tahur water, other than earth and the like,