First: No specified number of washings is required in such cases, whether the impurity results from a dog’s lapping or anything else.

Second: The water need not drain away from the site of the impurity.

Third: The washwater is pure even before it drains away from the site of the impurity.

Accordingly, we say: Whatever urine or other impurity was on the bathhouse floor has subsequently had water flow over it. The floor has therefore become pure, and the washwater is also pure. Once the washwater from the floor is deemed pure, the doubt is entirely dispelled.

If someone says, “Some of this water may have been used to remove impurity from a body, a vessel, or a garment,” the response is:

Even if this washwater is impure and reaches the floor, it is no worse than urine falling on the floor. If that impurity can be removed while the washwater remains pure even before draining away, then this applies all the more to the washwater in question.

Nor may he say, “The impurity is absent, but it is doubtful whether purifying water has flowed over the area—especially since the water flowing over it may be incapable of removing impurity, because it has already been used or has been altered by pure substances.”

The response is: We are not discussing a particular impurity that is absent and whose removal is doubtful. Rather, we are discussing what ordinarily happens.