Must the foot be washed if it gets wet with wudu water that fell on impure ground?

The default state of a bathroom floor is purity, and it is not ruled to be impure except with certainty. If the impurity of the floor is certain, then water purifies it if it removes the physical impurity or covers the legal impurity. However, if the floor is not purified, then water that touches the affected impurity is ruled to be impure, and the foot or anything else must be washed if it touches this impure water. But washing is not obligatory unless there is certainty of the transfer of impurity, as doubt is not sufficient to rule on its transfer.