Pool leak when pump is running

[Skwj]

Hi all,

I have an issue with my pool in that it leaks from ‘somewhere’ when the pump is running. To give you some background, I have a 50,000L concrete chlorine pool with a sand filter but not chlorinated.

The pool is located on a slopes piece of land with a driveway that runs alongside the side of the pool. Whenever the pump is running, I see water leaking on the base of the driveway that trickles down towards the street. When the pump is off, no water leaking.

I have tried the bucket test and can confirm no water leaking when pump is off but definitely leaking when pump is on.

My return jets are located opposite side of the driveway on the other side of the pool. Skimmer box is located on the high end of the driveway and about 2 metres from filter. Main drain is located around the middle of the pool slope. The water seems to be leaking in a location that has nothing nearby (main train and skimmer box uphill. Return outlets other side )

I’m sure not where this water is sourcing from. Initially I thought it was the drainage pipe for backwash and waste as that pipe runs directly alongside the driveway but when the pump is running on filter mode, I open the waste pipe from the filter and nothing comes out. I checked under the pool deck to inspect any dampness or water at he base of the concrete pool but nothing. I checked the return jet pipes under the deck and also no leak.

The closest thing that is near the Leak is the main drain but that is about 1.5 metres up the slopes driveway. I don’t see why the pipes would go down and then back up. It appears the main drain and the skimmer box is connected together. The previous pool owner has blocked the main drain and the skimmer box main drain inlet. I suspect that he did this for a reason to hide the leak.

Any ideas or further troubleshooting steps before I call in someone for a pressure test ?

Thanks in advance

[Denniswiseman]

If the leak is only when the pump is running then it's on the pressure side not the suction side (your filter and pool returns)

[Teapot1]

Seconded.