We have this problem with the box that houses the pump and the filter for the pool.
Whenever it rains, we get water in the bottom. Somehow, the water soaks through the paving and then seeps into the box as it runs down towards the drain.
The water has to get in through one of the holes where the pipes and the electric cable enter the box so I tried to seal them up with silicone which worked for a good while limiting the amount of water to less than an inch when we had a downpour.
When the pipe from the box to the skimmer was replaced, I investigated further to try and stop the leak altogether. That was when I discovered that it was actually the hole where the pipe that supplies water to top up the pool that was the most likely cause of the problem. All the installers had done was to cut a hole in the box and push the tube through. You can actually move the pipe up and down in the hole.
I tried sealing it with silicone again but made a poor job of it. Silicone won’t stick to anything wet so the leak continued. I then tried a different sealant which I hoped would stick and waited for the next rain.
As if to confirm that the sealant I’d used was useless, it poured with rain from Friday afternoon, all night and into Saturday morning. As a result you can see the amount of water in the box which was matched by a good two inches of water added to the pool itself. Luckily I’d isolated the electricity from the box because, as you can see, the pump was halfway submerged.
I’ve bailed all the water out now and left the pump to dry out. I’ve also carefully worked bathroom grade silicone into the joint where the arrow points and will add more to try and finish off the seal and then fingers crossed that I’ve managed to stop the leak or at least reduce it to a trickle,
Of course, my problem is a nuisance but it hardly bears comparison to those people whose houses have been flooded or the shops that have lost all their stock. Even if the pump was ruined, it wouldn’t cost the earth to replace it.