Basement bath plumbing rough in allowing ground water to enter
We have a full bath in our basement. The plumbing for the shower has a 10" deep square hole cut in the foundation to allow for the shower drain trap. This hole is lined with a thick black material. However, it has a hole in the bottom about the size of a quarter. I assume this is to be used as a drain in case of a leak (I have inspected the plumbing and can find no leaks). Since their is about 3/8" of water in the bottom of this hole, I am assuming the ground water is coming up through this quarter sized whole(we are experiencing extremely high water table -- the highest in 30+ years).
I would like to find something that would plug this hole. Maybe some type of water proof epoxy.... something... that I could cover the hole with and then dry up the existing water in the hole.
Any advice or help on this would be greatly appreciated.