Is water that falls from the site where impurity (urine splattered on the leg) was removed, down to the lower leg or foot, considered impure, and does it necessitate rendering whatever it touches impure?

Water that separates from an impurity after its removal is pure if it has not changed, but if it separates from it having been altered by the impurity, then it is impure. However, if it separates from the impurity before its removal without having changed, some scholars consider it impure due to its contact with the impurity, while others consider it pure because it has not changed. Water is considered pure if it separates from urine splash after purification without undergoing any change.