Hi, thanks for using JustAnswer.com. I suspect the drain in the freezer may be frozen and allowing the defrost water to pool in the bottom of the freezer. Over time, this pooling water will build up enough to push any new water past the freezer and run down the cabinet seams and look to be coming from all kinds of strange areas where water should not be. Look in the freezer section, do you see water frozen on the floor?
The water tank in the refrigerator, okay. It will need to be replaced. It is available HERE for $18.71. It is number 810 in the picture.