If the pump mount is screwed to what looks like a 3-4 square in the bottom of the bilge,most likely it has wood underneath the fiberglass and the wood is rotting.
If this wooden square rots away,it's not that much of an issue.

Same thing if it is a stringer that runs front to back in the bottom of the boat.
Hopefully it is not a stringer you are talking about.
Don't need water soaked stringers.