WE had the same problem with water behind our liner in the shallow end of our pool. It got bad. We used a hose attached to a pump to suck out the water. It was horrible. Our pool was dug too low, and we never had ground water before the pool started. The hole dug was dry during excavation. We just always had to use thehose/ pump behind the liner after a rain. We eventually moved. How bad is your problem???