The pool I look after has a small crack in the base of the pool about the size and shape of a horseshoe. When the pool is empty, water enters the pool through this crack, so I guess that means that the water table is high. The pool is built part way up a slope - ground rises behind it, and there is a 4' step down on the other side.
This year, the crack was filled with epoxy so that children don't stub their toes on it, but a pencil sized hole was left to prevent water pressure from building up underneath and bursting open a bigger hole. If you put weight on the part of the pool next to the crack, you can get it to move - so who knows what's going on under there.
Our pool man has suggested that this autumn we could find out what's going on under there by digging it up, and then putting in a pipe under the pool to take the "spring" water away by making a channel in the pool base, putting in a pipe and then mending things afterwards so you can't see any of this.
I've also noticed that there is also a crack in the coping and top of the skimmer channel on the short side facing across the slope, and the other skimmer, which is on the downhill side of the long side, is at least an inch lower. Part of me thinks the pool is cracked and heading slowly down the slope - although it is going very slowly as the pool is 45 years old.
I'm wondering if we would be better off leaving well alone, or is this work necessary? I don't want to turn up something that would leave us with a huge bill as we can't afford it.
Is there anything non-destructive I can do to investigate the integrity of the pool structure?