Pool leaking 12 cm per day?

[ChomDo]

Hi,

 

I wrote about my pool leak some months ago and now the situation has gotten a lot worse. So my small concrete pool (2x3m) was constructed just 6 months ago and in the very beginning the water level went down about 1 cm per day. We got into a fight with the irresponsible pool company because of the leak and other issues so we just let it be at first. After a few months use the pool started leaking at a rate of 4 cm per day. We always saw water outside of the pool at the pool light area so we were pretty sure the problem was there. Now the pool has been empty for about a month and we got a plumber to seal the pool lighting area better. 

 

So yesterday I filled the pool and now the water level had gone down 5 cm in 10 hours that would be 12 cm per day. I have no idea whats going on but that's about 500 litres of water flowing out of somewhere in one day (my pool 120cm deep and 5 cubic metres).

 

Of course I now have to hire another pool company to find out where the leak is. I'm just worried that if it's for example one of the main pipes under the concrete structure then the job would be big and expensive.

 

Any ideas on cases like this? What could be causing a leak of this scale? There is no visible leakage anywhere either so that 500 litres must be going somewhere under ground.

 

 

[grollies]

Start by emptying the pool and testing your pipes. Depending on the configuration simply plugging the low end and filling to the high points and doing a static head test will be sufficient.

 

While it was empty you checked the structure for cracks right?

[SwimmingPoolsThailand]

There could be several reasons. Discounting evaporation for  which this leak is obviously  too much:

• No waterstop strip in the concrete wall/floor joint -  strip the tiles prepare the substrate and re-tile
• Non use of waterproof concrete - strip the tiles prepare the substrate and re-tile
• Non use of waterproof rendering - strip  the tiles prepare the substrate and re-tile
• Non use of special tile adhesive for pool - and/or tile adhesive incorrectly applied (Thai style) - strip the tiles, prepare the substrate and re-tile
• Non use of special tile grout for pools -  strip the tiles, prepare the substrate and re-tile
• Fractured piping -  difficult if the pipes are underground or covered by concrete
• Leaks through the entries through the walls of pipes , lighting conduit, return jets,  and/or main drain - can be cured quite easily

[ChomDo]

28 minutes ago, grollies said:

Start by emptying the pool and testing your pipes. Depending on the configuration simply plugging the low end and filling to the high points and doing a static head test will be sufficient.

 

While it was empty you checked the structure for cracks right?

Thanks for the advice. No crack in the structure. I was thinking of lowering the water level by about 30 cm first so that most of the pipes are above water level (excluding main drain, one return and the jacuzzi suction) The pool is basically brand new so everything looks to be in perfect condition. The pipes were tested in the beginning after we discovered the water level went down 1 cm per day. This 12 cm per day leak I just can't understand at all. Unless a pipe under the pool is really broken but that should be quite unlikely right and those pipes are surrounded by solid concrete so how could 500 litres of water just flow out.  

 

 

[ChomDo]

9 minutes ago, SwimmingPoolsThailand said:

There could be several reasons. Discounting evaporation for  which this leak is obviously  too much:

• No waterstop strip in the concrete wall/floor joint -  strip the tiles prepare the substrate and re-tile
• Non use of waterproof concrete - strip the tiles prepare the substrate and re-tile
• Non use of waterproof rendering - strip  the tiles prepare the substrate and re-tile
• Non use of special tile adhesive for pool - and/or tile adhesive incorrectly applied (Thai style) - strip the tiles, prepare the substrate and re-tile
• Non use of special tile grout for pools -  strip the tiles, prepare the substrate and re-tile
• Fractured piping -  difficult if the pipes are underground or covered by concrete
• Leaks through the entries through the walls of pipes , lighting conduit, return jets,  and/or main drain - can be cured quite easily

Thanks for this list. I'm pretty convinced there's no structural leaking even though they for sure didn't perform all the above points correctly. I think the last two could be most likely. I sure hope it's the last one on your list as this would still be quite easy to fix.  

[SwimmingPoolsThailand]

3 minutes ago, ChomDo said:

Thanks for this list. I'm pretty convinced there's no structural leaking even though they for sure didn't perform all the above points correctly. I think the last two could be most likely. I sure hope it's the last one on your list as this would still be quite easy to fix.  

One way to check, because this is a small  pool,  is to  leave it  and let  it continue to leak. If the water stops going  down at  the level  of the entries through the walls of pipes, lighting conduit, return jets, chances are that's where the problem is.

[ChomDo]

10 minutes ago, SwimmingPoolsThailand said:

One way to check, because this is a small  pool,  is to  leave it  and let  it continue to leak. If the water stops going  down at  the level  of the entries through the walls of pipes, lighting conduit, return jets, chances are that's where the problem is.

That's exactly what I was planning on doing next. At least then if the leaking stops I can exclude the main drain and structural leaking. Those two options worry me the most since they would be the most difficult ones to fix.

[ChomDo]

So now after lowering the water level to the above mentioned height the leaking has reduced but in the last 5 hours the water level has gone down 1 cm. So that should mean that instead of leaking 12 cm per day it's now leaking 4-5 cm per day. Now I'm more confused. Could it just be that there are several different spots leaking or possibly the return pipe (my pool has two return outlets of which one is now below water and one above)?

Edited September 25, 2017 by ChomDo

[grollies]

If the leak is around your light conduits/return ports the leak rate will slow as the static head pressure (weight of water) decreases. Using this method you have to wait until the water level stabilises. That will be the level of the leak.

 

By your own estimation the initial leak rate is around 30 litres/hour which sounds to me more like a pipe fracture.

[ChomDo]

I was guessing something like that too. So now that the pool is half empty the leaking rate has gone down by half if that makes sense. So if this is correct the leak should be in one of the 3 remaining parts (jacuzzi suction, return pipe or main drain). It's just that the pool's water level is at about 60 cm now and all of those 3 inlets/outlets are at ground level so with waiting where the leak stops wouldn't help much right? It could still be any of those 3. 

 

The initial leaking rate was 5 cm for the first 10 hours and finally about 10 cm for the first 24 hours. So the initial leak rate must have been around 20 litres/hour.

 

I'll have to find a pool company to fix it anyway but I just prefer to collect as much information by myself first. After the experience of having this pool built I have a hard time trusting any Thai pool companies. If anyone has an idea of a more reliable pool company in Bangkok I would appreciate any hints?

[everett kendall]

15 hours ago, ChomDo said:

So now after lowering the water level to the above mentioned height the leaking has reduced but in the last 5 hours the water level has gone down 1 cm. So that should mean that instead of leaking 12 cm per day it's now leaking 4-5 cm per day. Now I'm more confused. Could it just be that there are several different spots leaking or possibly the return pipe (my pool has two return outlets of which one is now below water and one above)?

I had a leak in the return pipe from the drain ( which is is under cement) we plugged it and no more leak. If I need to drain the pool I use a submerisable pump.

[JBChiangRai]

Keep it full for 24 hours, pump it out and look to see where the water is coming back in.

 

We build top-end houses with pools and identify difficult to find leaks this way.  As you pump it out, you might see dirty water entering the clean pool water somewhere or when it’s empty you should see water coming back in.  Emptying a pool can be risky, if the water table is very high it can pop out the ground, also sunlight on tiles may craze the glaze.  For this reason, we tile all our pools in granite, but the concrete and render needs to have had the proper waterproof additive as granite is porous.

 

if you have to retile, consider granite, it lasts forever and no re-grouting ever required.  It also looks a lot better.  

[Mattd]

What you do not state is if the pool is an overflow or skimmer type and if the leak gets worse with the pump on or off?

If it is an overflow type, then one of the first things to check is the surge tank for any cracks or leaks.

If it is a skimmer type, then lowering the level can be dangerous, as the skimmer section is normally set so that the pump takes suction from there, if the level of the pool goes below the skimmer box in the pool, then there is a possibility of damaging the pump due to sucking air through the skimmer box.

As mentioned by several others, other possible causes are cracked pipes, you could try sealing them off one by one, taking care that the pump still has suction, or turn it off whilst carrying out the tests.

The other possible area (and I hope not!) is the join between the floor of the pool and the sides, normally there is a rubber seal inserted here when the concrete is poured and it is critical that the floor is poured in one go and then the sides as one pour after.

I'd go for sealing off each pipe individually pool end first and monitoring the result, not forgetting the vacuum pipe etc. best to just turn the pump off whilst doing this, to avoid any damage.

[farang62]

That size pool looses a minimum of 500-600 liters of water from Evaporation alone, on a calm sunny day, more the stronger the wind and sun is out all day.

Running the pump timing is crucial as you move the water and expose more water to the air.

 

If you don't use the pool that often try and operate the pool pump at night when there is less wind and no sun.

[SantiSuk]

19 minutes ago, farang62 said:

That size pool looses a minimum of 500-600 liters of water from Evaporation alone, on a calm sunny day, more the stronger the wind and sun is out all day.

Running the pump timing is crucial as you move the water and expose more water to the air.

 

If you don't use the pool that often try and operate the pool pump at night when there is less wind and no sun.

Unless I am missing something (possible, so I'll just raise it as a query) I think that is a helluva'n overstatement for a 2 x 3 x 1.2 m small pool farang62. That would be about 8% a day). My pool is 15 x 4.5 x 0.8to1.8 m ie 13 times as much surface area. It loses under 0.5% per day, which I understand to be about normal.

 

Maybe you have a leak (or I have in-bound seepage ).

[janpharma]

17 hours ago, ChomDo said:

I was guessing something like that too. So now that the pool is half empty the leaking rate has gone down by half if that makes sense. So if this is correct the leak should be in one of the 3 remaining parts (jacuzzi suction, return pipe or main drain). It's just that the pool's water level is at about 60 cm now and all of those 3 inlets/outlets are at ground level so with waiting where the leak stops wouldn't help much right? It could still be any of those 3. 

 

The initial leaking rate was 5 cm for the first 10 hours and finally about 10 cm for the first 24 hours. So the initial leak rate must have been around 20 litres/hour.

 

I'll have to find a pool company to fix it anyway but I just prefer to collect as much information by myself first. After the experience of having this pool built I have a hard time trusting any Thai pool companies. If anyone has an idea of a more reliable pool company in Bangkok I would appreciate any hints?

We faced the same problem and after having emptied the pool 8 times ...we decided to remove it.  That pool was made by a non-Thai company.  If you PM me I will let you know which company you certainly don't have to use.

[ChomDo]

3 hours ago, everett kendall said:

I had a leak in the return pipe from the drain ( which is is under cement) we plugged it and no more leak. If I need to drain the pool I use a submerisable pump.

That I was thinking of doing already if there really is a leak in the main drain. I can also just use a plug and take the plug off when I want to backwash or drain the water out right? I mean I don't want it permanently closed.

[SwimmingPoolsThailand]

Can you post a photo of this maindrain?

[ChomDo]

3 hours ago, JBChiangRai said:

Keep it full for 24 hours, pump it out and look to see where the water is coming back in.

 

We build top-end houses with pools and identify difficult to find leaks this way.  As you pump it out, you might see dirty water entering the clean pool water somewhere or when it’s empty you should see water coming back in.  Emptying a pool can be risky, if the water table is very high it can pop out the ground, also sunlight on tiles may craze the glaze.  For this reason, we tile all our pools in granite, but the concrete and render needs to have had the proper waterproof additive as granite is porous.

 

if you have to retile, consider granite, it lasts forever and no re-grouting ever required.  It also looks a lot better.  

Thanks for the advice. I've done that too and the only water that sprays back in for 2 seconds is from the return pipe when I switch the sand filter leaver from "filter" mode to "closed". This is normal I guess that it just releases the remaining water in the pipe back to the pool. When the pool was empty for a month the lower return hole at the bottom did have some black liquid coming out but it was raining a lot so I thought it was just dirt at the end of the pipe that got rain. Also when I filled the pool and switched the pump on for the first time that lower return sprayed in like one blow of dirty black water. That took just a second and after that everything was normal and water clean.  Would this information mean anything?

[ChomDo]

3 hours ago, Mattd said:

What you do not state is if the pool is an overflow or skimmer type and if the leak gets worse with the pump on or off?

If it is an overflow type, then one of the first things to check is the surge tank for any cracks or leaks.

If it is a skimmer type, then lowering the level can be dangerous, as the skimmer section is normally set so that the pump takes suction from there, if the level of the pool goes below the skimmer box in the pool, then there is a possibility of damaging the pump due to sucking air through the skimmer box.

As mentioned by several others, other possible causes are cracked pipes, you could try sealing them off one by one, taking care that the pump still has suction, or turn it off whilst carrying out the tests.

The other possible area (and I hope not!) is the join between the floor of the pool and the sides, normally there is a rubber seal inserted here when the concrete is poured and it is critical that the floor is poured in one go and then the sides as one pour after.

I'd go for sealing off each pipe individually pool end first and monitoring the result, not forgetting the vacuum pipe etc. best to just turn the pump off whilst doing this, to avoid any damage.

Oh did I not, sorry. I have a skimmer (excluded already because leaking below skimmer level). Leaking is the same pumps on or off. Of course I don't use the pump when the water is below skimmer level. Just for draining purposes only. That's why I wasn't able to use the pump long since the water level went below skimmer in a few hours.  

 

I do suspect the one of the 3 remaining pipes or the plugging round then (but 500 litres per day probably can't run out of the plugging around a pipe right). I do also know that the very unprofessional company that built our pool did not do anything perfectly correctly and they for sure didn't use a rubber seal between in the joints. If I had known more about pools at that time I wouldn't have accepted any of their methods. When I look trough the tiles and the whole structure I don't see any problems or any kind of cracks. Even if I don't see anything is it possible that the water would be escaping trough the tiles and the whole concrete structure? Of course soon I'll know more when I can get the 3 remaining pipes checked. I don't have any rubber plugs to do the testing now but I guess fixing it I couldn't do by myself anyway so probably will just let a pool company do both.

[ChomDo]

3 hours ago, farang62 said:

That size pool looses a minimum of 500-600 liters of water from Evaporation alone, on a calm sunny day, more the stronger the wind and sun is out all day.

Running the pump timing is crucial as you move the water and expose more water to the air.

 

If you don't use the pool that often try and operate the pool pump at night when there is less wind and no sun.

Hmm maybe you read the pool size wrong. It's 2x3 m and about 5 cubic meters. Loss of water when full was 10-12 cm per day (400-500 litres) close to 10 %. 

 

I normally use the pool twice a day or more so it's a real pain in the ass to not be able to use it for a long time now.

[ChomDo]

3 hours ago, farang62 said:

That size pool looses a minimum of 500-600 liters of water from Evaporation alone, on a calm sunny day, more the stronger the wind and sun is out all day.

Running the pump timing is crucial as you move the water and expose more water to the air.

 

If you don't use the pool that often try and operate the pool pump at night when there is less wind and no sun.

Hmm maybe you read the pool size wrong. It's 2x3 m and about 5 cubic meters. Loss of water when full was 10-12 cm per day (400-500 litres) close to 10 %. 

 

I normally use the pool twice a day or more so it's a real pain in the ass to not be able to use it for a long time now.

 

Here are a few general pictures from the time the pool was constructed (6 months ago) and of the main drain when they were testing it.

[khunPer]

On 9/24/2017 at 11:08 AM, ChomDo said:

The pipes were tested in the beginning after we discovered the water level went down 1 cm per day.

1 cm a day is very normal level decrease caused by evaporation, can even be more like 2-3 cm; but 10 cm a day is a leak somewhere. First check that circulation pump and filter and Jacuzzi pump(s) are not leaking (wet anywhere) – just a rubber seal leak in the circulation pump can drain several centimeters in a small pool. As others have stated, be careful not to damage the circulation pump during checks and when changing water levels – believe you got some good advises in previous posts. 

(FYI: I have a 2.5m x 3m Jacuzzi-pool also, about 1m deep.)

[dpdp]

How much did you pay for the pool ? This is usually what happens when people try to save money to build a cheap pool.

For such a small bassin I don't think it was worth trying to save anything.

 

 

[ChomDo]

4 hours ago, dpdp said:

How much did you pay for the pool ? This is usually what happens when people try to save money to build a cheap pool.

For such a small bassin I don't think it was worth trying to save anything.

 

 

Of course we didn't want to overspend either but in the end we only found one company in BKK willing to build a concrete pool this small so there wasn't a lot of choice. We did get a few wild quotes from other companies (around 400,000b) but they clearly didn't want to build a small pool because they were charging the same as for a pool twice or three times the size of ours. 

 

Our pool was around 230,000b but due to countless arguments with the company we didn't pay the last 20 % or so. What we paid in the end was around 180-190,000 but of course the cost of fixing all their mess ups we might end up paying a lot more than the original sum.

 

 

[dpdp]

1 hour ago, ChomDo said:

Of course we didn't want to overspend either but in the end we only found one company in BKK willing to build a concrete pool this small so there wasn't a lot of choice. We did get a few wild quotes from other companies (around 400,000b) but they clearly didn't want to build a small pool because they were charging the same as for a pool twice or three times the size of ours. 

 

Our pool was around 230,000b but due to countless arguments with the company we didn't pay the last 20 % or so. What we paid in the end was around 180-190,000 but of course the cost of fixing all their mess ups we might end up paying a lot more than the original sum.

 

 

 

Clearly you will have to totally rebuild the pool.

Sorry but spending less than 1 million even of a small pool is not a smart way to go.

A pool is not cheap and it even happens that some people have problems when paying a high price, so how can you expect getting something good for the price of a motorbike ?

Sorry, no offense, but just trying to tell you that what happened is just normal.

 

 

 

 

 

 

 

[janclaes47]

Just now, dpdp said:

Sorry but spending less than 1 million even of a small pool is not a smart way to go.

[whaleboneman]

13 hours ago, ChomDo said:

Thanks for the advice. I've done that too and the only water that sprays back in for 2 seconds is from the return pipe when I switch the sand filter leaver from "filter" mode to "closed". This is normal I guess that it just releases the remaining water in the pipe back to the pool. When the pool was empty for a month the lower return hole at the bottom did have some black liquid coming out but it was raining a lot so I thought it was just dirt at the end of the pipe that got rain. Also when I filled the pool and switched the pump on for the first time that lower return sprayed in like one blow of dirty black water. That took just a second and after that everything was normal and water clean.  Would this information mean anything?

That's your leak. If you chop this pipe at the pump and fit a temporary pipe into the pool you may be able to prove it for sure. Making a permanent repair will be more difficult but can be done.

[whaleboneman]

I thought about this some more. I think the pipe to the lower discharge to pool is the problem and the fact that dirty water was coming out makes me think the leak is in dirt. You could dig straight down beside the pool to get at the leak and make a repair. In this way, the pool would not have to be disturbed. Just have to smash away the concrete skim coat beside the pool. 

Good luck.

[Sydebolle]

Let the water leak on its own. If it should stop leaking then you have the height of the leak established and a professional pool company will be able to take it from there.