I was preparing to open the pool and noticed that there was a substantial drop of the water level from when I closed it. As I pulled back the cover I noticed that there was a large amount of water between the liner and the walls of the pool- worse in the shallow end than the deep end. I have been told this could be ground water. The pool is only one year old. Could this have been caused by anything else ( ruptured / frozen pipe, hole in the liner etc.)?

Is this an above ground pool or in ground concrete with liner?

In ground with a vermiculite bottom and vinyl liner