18. It is permissible to place a container under a leak on Shabbos, and,
when it fills up, to pour it out, and then return it to its place; this
applies only if the dripping water is fit for washing one's body. If,
however, the water is repulsive ("me'usim"), it is forbidden to place a
container there, because it is forbidden to intentionally create a "graf
shel re'ee" (lit: "bedpan", but refers to any repulsive item) on
Shabbos. If one transgressed and placed it there, and it was in a place
where the repulsiveness affected him, it may be removed.