Leaking skimmer line

[mas985]

Since I can't find the leak location, I consider emptying my pool indefinitely.

Don't give up quite yet!

Have you let the pool sit with the pump off and see if the water level stops at a certain point? This can help determine where the leak is.

Also, if you are willing, you can pressure test certain sections of pipe to determine where the leak is.

I have a 6 x 11 meter inground pool, and it is more a burden than it is an enjoyment.
The house with pool was built 15 years ago, but I very rarely use the pool, and I'm single. At the same time it has to be maintained, and it actually prevents me from traveling for an extended period of time, because of that.
So I consider from emptying it and covering.
I have read on the internet about pools that get lifted out of the ground, or get cracks in the floor, because of the groundwater.
My pool is tiled concrete.
What are the risks here, considering I live in a flood free area. I have a 35 meter deep borehole, and I have to put a timer on it, otherwise the pump runs dry after 10 minutes.

That indicates ground water can be a problem. However, if you drain the pool, it becomes an even bigger problem because you basically can't have any water in that bore hole or you risk raising the pool when it is empty. So if the sump pump fails or does not go on when you need it to, you may have an issue.

Does the pool itself have a hydrostatic valve in the bottom? If so, that can help release any pressure that builds up but they are notorious for failing so if you did drain the pool, I would put in a new one.

 

[jan verbeem]

That indicates ground water can be a problem. However, if you drain the pool, it becomes an even bigger problem because you basically can't have any water in that bore hole or you risk raising the pool when it is empty. So if the sump pump fails or does not go on when you need it to, you may have an issue.

Not sure if I'm misunderstanding this.
The borehole is on a timer, because after 10 minutes it runs dry, which indicates the groundwater level is very low, which I thought is a positive in my case.
The timer then stops the pump for 30 minutes, after which there is enough water to pump 10 minutes full power.
The borehole also don't provide water directly to the pool, for that I have 7500 liter of inground storage tanks.

Does the pool itself have a hydrostatic valve in the bottom? If so, that can help release any pressure that builds up but they are notorious for failing so if you did drain the pool, I would put in a new one.

The pool doesn't have a hydrostatic valve, that is something not heard from in this neck of woods. I'm in Thailand.

Also, if you are willing, you can pressure test certain sections of pipe to determine where the leak is.

Not possible to pressure certain sections, because the pipe is completely covered by a concrete sundeck from the skimmer end to the pump house, and there is no leak in the pump house, because that can be easily eyeballed.
The leak is in the skimmer pipe, because I can close the skimmer with a screw stop, and then there is no water loss.

 

[mas985]

Not sure if I'm misunderstanding this.
The borehole is on a timer, because after 10 minutes it runs dry, which indicates the groundwater level is very low, which I thought is a positive in my case.
The timer then stops the pump for 30 minutes, after which there is enough water to pump 10 minutes full power.
The borehole also don't provide water directly to the pool, for that I have 7500 liter of inground storage tanks.

The fact that you have a bore hole means the water table can be an issue otherwise you wouldn't have one at all. When there is no water in the pool, any amount of water underneath can then become an issue.

The pool doesn't have a hydrostatic valve, that is something not heard from in this neck of woods. I'm in Thailand.

Understood.

Not possible to pressure certain sections, because the pipe is completely covered by a concrete sundeck from the skimmer end to the pump house, and there is no leak in the pump house, because that can be easily eyeballed.
The leak is in the skimmer pipe, because I can close the skimmer with a screw stop, and then there is no water loss.

Both ends of the skimmer suction pipe are available so you definitely can pressure test that section of pipe. You only need to have access to the pipe ends, not the pipe itself.

You simply plug each end of the pipe (skimmer plug, pump inlet plug) with a fitting to pressurize the pipe. This will isolate that section of pipe and allow for pressure testing.

 

[mas985]

This might help:

 

[jan verbeem]

The fact that you have a bore hole means the water table can be an issue otherwise you wouldn't have one at all. When there is no water in the pool, any amount of water underneath can then become an issue.

I have a borehole to provide water to the house, irrigation system and pool, because I have no city water.
Since the borehole pump hangs at 35 meter depth, and runs dry after 10 minutes, indicates to me that there is no water under the pool which is 1.5 meter in the ground..

Both ends of the skimmer suction pipe is available so you definitely can pressure test that section of pipe. You only need to have access to the pipe ends, not the pipe itself.

I'm well aware of that, but what is the point of detecting that the leak is somewhere in the 12-meter under a concrete sundeck, when I have no intention of demolishing the sundeck anyway? If the leak was in the pump house i would have found and fixed it already.
There is also no doubt that the leak is in the skimmer pipe, because I screw a stop in the bottom of the skimmer, and the pool isn't losing a drop of water. I still have vacuum feed and floor drain open during that time

 

[jan verbeem]

This might help:

After watching your video I now better understand why you insist on the pressure test. The only issue here is to find the equipment for that, and then I think particularly on the listening device.

 

[mas985]

You can do the pressure testing without the listening device although it won't pin point the exact location, just the section of pipe where the leak occurs.

Also, a pool will stop leaking when the pool level reaches the level of the leak so if you leave the pool pump off long enough, it should show you at what elevation the leak might be. This can useful to determine if the leak may be at the skimmer/pipe connection or perhaps at a location that is easier to access. If so, that may be easy to fix without ripping out all the concrete.

Basically, the more information you have about the leak, the better decision you can make about how to proceed.

Have you tried calling some of the pool services in Thailand to see if they can do the testing and/or can recommend someone to do it?

Renovation And Repair - Thailand Swimming Pools

Do Remember – An Inefficient, Badly Managed Pool Costs You Extra Money!

www.thailandswimmingpools.com

Leading Thailand Swimming Pool Equipment Shop

www.thailand-pools.com

 

[jan verbeem]

You can do the pressure testing without the listening device although it won't pin point the exact location, just the section of pipe where the leak occurs.

Also, a pool will stop leaking when the pool level reaches the level of the leak so if you leave the pool pump off long enough, it should show you at what elevation the leak might be. This can useful to determine if the leak may be at the skimmer/pipe connection or perhaps at a location that is easier to access. If so, that may be easy to fix without ripping out all the concrete.

Basically, the more information you have about the leak, the better decision you can make about how to proceed.

Have you tried calling some of the pool services in Thailand to see if they can do the testing and/or can recommend someone to do it?

Renovation And Repair - Thailand Swimming Pools

Do Remember – An Inefficient, Badly Managed Pool Costs You Extra Money!

www.thailandswimmingpools.com

Leading Thailand Swimming Pool Equipment Shop

www.thailand-pools.com

Yes I know them, as I have dealt with them previously. The company is run by a foreigner, who charges prices similar to what you would pay in the west.
Take note, in Thailand the foreigner is not allowed to work, and a Thai technician earns about 50 US$ a day. They are located 600 km from where I am, which means they would already charge 2 days for travelling alone.
The companies that are active near here are cowboys.
I do some research on the listening device. Maybe someone on a local forum can provide tips on that.
Thank you for your help and advice, the videos you posted were really useful to make me understand how a pressure test can detect the location of the leak.

Though my question about what are the risks of emptying the pool still stands, as the pool really is a burden, more than a convenience. If I use it once a year, I don't exaggerate.
I was thinking about this already before I had the leak, and the current situation has only sped up those thoughts.
First I was thinking about making a flowerbed of it, but some friends advised against that, with the argument that if I ever sell the house the buyer would not be able to recover the pool.

 

[mas985]

I have no real intention to dig up all the concrete, because I have a vacuum feed and a bottom drain to feed the pump.

Are you sure you don't have a hydrostatic valve in the main drain sump? That is where they are usually located.





You can always drill a hole through the bottom to prevent it from lifting.

 

[jan verbeem]

My leak got fixed, it was the first pipe elbow about 50cm from the skimmer that had cracked. Pretty strange since it is class 13.5 Upvc. Probably a manufacturer fault in the part.
I now also discovered that the pipe from skimmer to pump doesn't go under concrete. They laid it at the other side of the pool under gravel and river rocks, because there is a large drain pipe in there to handle the water during heavy rains when the pool overflows.
All good, cost me about 120 AUS$ in labor and parts