Underground water leak - where to start !!

[Andrew Dwyer]

Okay, about a month ago my water pump started pulsing when no water is being drawn off, initially once an hour but now more frequently ( about every 15 minutes ) .

 The pulse is a short burst just enough to bring the pressure back up.

The pump is located outside my bedroom window so I know exactly when it started and the frequency now.

By using stop valves before and after the pump I have eliminated the pump as being the problem ( the pressure is held with valve closed directly after the pump ).

Likewise I have stop valves on incoming water to toilets and sinks, showers are visibly not leaking so am 99.9% sure it is not at any tap or ballcock etc and is in the pipe work from the pump under the house or concrete walkways. I have spent some time everyday looking for any telltale signs, lifting tiles or any damp looking grout even etc. but of course that would be too easy ????

 

Soo, I now have the dubious honour of trying to find the leak !!

After the pump the pipework goes under the concrete walkways ( now tiled ) and goes around the house approx 180 degrees that I know of, kitchen and bathroom are all located in the back half of the house. What I don’t know is where It enters under the house and if it enters in one place only or at each point ( bathroom, kitchen etc ), am hoping to contact the house builder for some guidance on where the pipes run.

 

My intent is to find the point where the pipe work goes into the house and put a temporary cap to determine if in walkways or under house, if it turns out that the leak is under the walkways ( feasible as they were tiled 6 months ago ) then I have a chance to repair, probably leaving above ground .

If of course the leak is somewhere underneath the house then the nightmare begins and getting the new pipes into bathroom ( x 3 ) and kitchen ( x 1 ) fills me with dread.

 

Soo, looking for some advice on how to track the leak or should I just bite the bullet and start to prepare for new pipework altogether ??

 

TIA Andy .

[frequentatore]

I guess you have galvanized pipes underground (and maybe inside the house?). The pipes get so much rust inside over the years, they leak or you get very low pressure.

I replaced everything by plastic pipes in a shophouse and an apartment.

[Andrew Dwyer]

8 minutes ago, frequentatore said:

I guess you have galvanized pipes underground (and maybe inside the house?). The pipes get so much rust inside over the years, they leak or you get very low pressure.

I replaced everything by plastic pipes in a shophouse and an apartment.

The house is about 4 years old, pvc pipes.

[lopburi3]

You have a pump providing what PSI/BAR pressure?  Most Thai pipes are not designed for more than low pressure well pump - and the older the less likely they can handle.  You have turned all supply lines off for sure for sure (they may not close completely) - very important to check toilets extra close - lower water and check that it does not increase in holding tank.  

 

But in the event of the worst it is not hard to run good plastic above ground lines and does not take long.  You can paint to match walls and they do not look bad at all when held with the plastic clips.  Have 7 bath home done that way.  

[Kwasaki]

1 hour ago, Andrew Dwyer said:

Soo, looking for some advice on how to track the leak or should I just bite the bullet and start to prepare for new pipework altogether ??

Well you could turn pump off and put some radweld from the inlet govt supply into the pipe system.

Unless you can locate the place where the pipe leaks very difficult without out digging it all up.

If you can isolate sections to locate the leak see if it is possible to run surface pipes.

[Andrew Dwyer]

26 minutes ago, lopburi3 said:

You have a pump providing what PSI/BAR pressure?  Most Thai pipes are not designed for more than low pressure well pump - and the older the less likely they can handle.  You have turned all supply lines off for sure for sure (they may not close completely) - very important to check toilets extra close - lower water and check that it does not increase in holding tank.  

 

But in the event of the worst it is not hard to run good plastic above ground lines and does not take long.  You can paint to match walls and they do not look bad at all when held with the plastic clips.  Have 7 bath home done that way.  

On at 20.3 psi , it’s the smallest of 5 Hitachi Well/constant pumps and standard in the Moobahn, only single story .

Yes, checked and double checked toilets. 
 

Outside it’s fairly straightforward to come off the pump and go round the house, teeing off for 3 points, and getting into 1 point in the kitchen is easy as it’s under worktop and behind cabinet doors. It’s 4 points in each bathroom that will take a bit of planning, concrete walls will test my patience for sure.

[Andrew Dwyer]

14 minutes ago, Kwasaki said:

Well you could turn pump off and put some radweld from the inlet govt supply into the pipe system.

Unless you can locate the place where the pipe leaks very difficult without out digging it all up.

If you can isolate sections to locate the leak see if it is possible to run surface pipes.

Yes i have an idea that from the pump it goes a third of the way round to existing stand pipe and tap, I think that is where it then goes into the house, seems like the ideal place to test, i’ll end up digging that up and cap the house off from the walkways then try the pump.

 

[Bangkokhatter]

Before you start digging up concrete i would make sure you are 100% sure it is an internal leak.

Last year my pump started doing exactly the same thing and i was advised by 2 contractors it was an internal leak, However i actually lifted off the water tank lid and looked at the water level every time the pump started with no service opened, the water level did not drop.

I thought if there was internal leak the water level must go down.

Eventually a third contractor installed a non-return valve in the outlet and problem solved. 

Edited February 14, 2020 by Bangkokhatter

[saengd]

Is it possible the bladder tank has a leak, that would certainly give you the short burst pulsing you describe? Perhaps take the cover off the pump and unscrew the bladder tank (isolate the pump first) from the body of the pump and stick a pencil or stick inside the tank to see if the bladder has perforated and the gas leaked out.

 

Replacing the bladder tank is easy enough and inexpensive. We had the exact same symptoms two months ago and a new bladder tank solved the problem nicely.

Edited February 14, 2020 by saengd

[moe666]

7 minutes ago, saengd said:

Is it possible the bladder tank has a leak, that would certainly give you the short burst pulsing you describe? Perhaps take the cover off the pump and unscrew the bladder tank (isolate the pump first) from the body of the pump and stick a pencil or stick inside the tank to see if the bladder has perforated and the gas leaked out.

 

Replacing the bladder tank is easy enough and inexpensive. We had the exact same symptoms two months ago and a new bladder tank solved the problem nicely.

I had the bladder leak and the water developed a very bad taste and smell. Yess could be a bladder leak in the expansion tank

[chickenslegs]

Hi Andrew

IME - It's almost always a leaking toilet, and the leakage is often so small as to be invisible.

Yes, you closed the stop-valves, but they sometimes fail (or were never 100%).

Before doing anything drastic, try adding a few drops of food colouring to your toilet cisterns and wait for a couple of hours.

[Andrew Dwyer]

8 minutes ago, Bangkokhatter said:

Before you start digging up concrete i would make sure you are 100% sure it is an internal leak.

Last year my pump started doing exactly the same thing and i was advised by 2 contractors it was an internal leak, However i actually lifted off the water tank lid and looked at the water level every time the pump started with no service opened, the water level did not drop.

I thought if there was internal leak the water level must go down.

Eventually a third contractor installed a non-return valve in the outlet and problem solved. 

I have a non return valve fitted in the inlet of the pump, I tested this wasn’t allowing water out backwards and lowering the pressure by closing a stop valve just before the pump, after about 10 mins the pump sensed a loss in pressure and kicked in, with the valve closed was unable to suck water and made a right old racket.

But it proved that the pressure still dropped even though the water had nowhere to go , other than the pipework.

[Andrew Dwyer]

10 minutes ago, saengd said:

Is it possible the bladder tank has a leak, that would certainly give you the short burst pulsing you describe? Perhaps take the cover off the pump and unscrew the bladder tank (isolate the pump first) from the body of the pump and stick a pencil or stick inside the tank to see if the bladder has perforated and the gas leaked out.

 

Replacing the bladder tank is easy enough and inexpensive. We had the exact same symptoms two months ago and a new bladder tank solved the problem nicely.

I am tempted to try the bladder tank as, as you say, it’s easy enough.

I closed a stop valve right after the pump and it sat there for a couple of hours with no cycling/pressure loss so am convinced the pump is holding pressure.

[Andrew Dwyer]

I did test the pump before by using 2 stop valves ( 1 before and 1 after pump )

 

Both valves closed - no cycling 

Outlet valve closed  - no cycling 

Inlet valve closed - after 15 mins pump cycling i.e. pressure loss from pipework.

[lopburi3]

7 minutes ago, Andrew Dwyer said:

I did test the pump before by using 2 stop valves ( 1 before and 1 after pump )

 

Both valves closed - no cycling 

Outlet valve closed  - no cycling 

Inlet valve closed - after 15 mins pump cycling i.e. pressure loss from pipework.

But do you have a pipe from output of pump back to supply water line?  Often there is so if mooban water pressure is higher than pump water flows directly.  And for that they have an automatic stop valve which can and do fail - a grit of sand on that could be enough to loose the amount of water you appear to be missing.  I have manual stop valve to supply source which keep closed unless have a pump/tank problem to avoid that issue (and want high pressure all the time) but the auto valves can fail.  

Edited February 14, 2020 by lopburi3

[Andrew Dwyer]

1 minute ago, lopburi3 said:

But do you have a pipe from output of pump back to supply water line?  Often there is so if mooban water pressure is higher than pump water flows directly.  And for that they have an automatic stop valve when can and do fail - a grit of sand on that could be enough to loose the amount of water you appear to be missing.  I have manual stop valve to supply source which keep closed unless have a pump/tank problem but the auto valves can fail.  

Yes I have a manual stop valve on my bypass also which is for pump or power failure, it’s always closed as my city water pressure is minuscule, if I open it the pump kicks in I.e. pumping water backwards.

Could be possibly slightly open with grit ?? , i’ll go and open and close it a couple of times to see if that does anything. If it is faulty or stuck slightly open I’ll still to do some digging as it’s halfway under the tiles.

 

Probably going use the bypass for the first time tonight as the pump cycling is keeping me awake ????

[Andrew Dwyer]

Keep the suggestions coming, I’m open to anything ????

[bwpage3]

If you never had this problem before the sidework work, I would start there.

[Kwasaki]

1 hour ago, Andrew Dwyer said:

Yes i have an idea that from the pump it goes a third of the way round to existing stand pipe and tap, I think that is where it then goes into the house, seems like the ideal place to test, i’ll end up digging that up and cap the house off from the walkways then try the pump.

 

Yeah sounds like you have good idea how to solve your problem, keep guys here informed.

I'm off TV for a few days or so, goodluck.

[Andrew Dwyer]

11 minutes ago, bwpage3 said:

If you never had this problem before the sidework work, I would start there.

It came about 6 months after I had the tiling done, not entirely convinced that’s where the leak is but hoping,  I have an idea at least where the pvc is so can replace that easily . But when it goes under the house to kitchen and bathroom it could go any which way ☹️

[Dumbastheycome]

So  if you allow the pump to reach switch off pressure and then you isolate it  from either  inflow or outflow it  maintains pressure. 

If  you then open inflow and the  pressure drops to  start pressure then  the internal backflow  valve is  faulty.

If you open outflow but  not supply recycle and pressure drops despite no open taps you have a leak.

But take special notice of  toilet cisterns for overflow which  can be  very subtle and deceptive.

Isolate them and see  what happens.

If that is  not  the  case then yes you  have to consider an enclosed pipe/joint  failure.

Sadly the  phenenomon for water  oozing  through the floor has been discounted as a miracle in my locality as a local residence for monks learned after extracting  many  Baht on the basis of. Happily a pvc piping  joint  that was not glued at all in installation does not  constitute a miracle...even in Thailand.

Not that that is any consolation in fixing the  ploblem.

Good luck.

[Andrew Dwyer]

3 minutes ago, Dumbastheycome said:

So  if you allow the pump to reach switch off pressure and then you isolate it  from either  inflow or outflow it  maintains pressure. 

If  you then open inflow and the  pressure drops to  start pressure then  the internal backflow  valve is  faulty.

If you open outflow but  not supply recycle and pressure drops despite no open taps you have a leak.

But take special notice of  toilet cisterns for overflow which  can be  very subtle and deceptive.

Isolate them and see  what happens.

If that is  not  the  case then yes you  have to consider an enclosed pipe/joint  failure.

Sadly the  phenenomon for water  oozing  through the floor has been discounted as a miracle in my locality as a local residence for monks learned after extracting  many  Baht on the basis of. Happily a pvc piping  joint  that was not glued at all in installation does not  constitute a miracle...even in Thailand.

Not that that is any consolation in fixing the  ploblem.

Good luck.

Yes, I now have no doubt it is a pvc pipe that has come “ unstuck “ and now sadly so have I !!

[Dumbastheycome]

5 minutes ago, Andrew Dwyer said:

Yes, I now have no doubt it is a pvc pipe that has come “ unstuck “ and now sadly so have I !!

I can only offer understanding of sentiment. I had a  failure despite that I did my own plumbing installation with  meticulous  care( I thought). I made the  mistake in  thinking  pvc components were all of same quality. A leak developed from piping in an internal wall . Luckily after ripping open the wall and hammer drilling away the  concrete floor I was able to expose a right angle union that was literally disintergrating !

Again luckily I was  able to  devise a repair with  little significant  damage. But it taught me to  only  buy the  ever so slightly  more expensive items  from major retail outlets.  No more  anything  from the "local shop  for local people".

External piping  may not be beautiful but as an alternative  cure at least relatively not expensive.

 

[saengd]

Yes I agree with the above. If it was me I think I'd probably go with new above surface pipework rather than potentially rip up the whole house trying to find that leak, you can box it in place, paint it, hide it or always ignore it.

 

Sorry you have to go through all that. 

 

 

[ravip]

10 hours ago, chickenslegs said:

Hi Andrew

IME - It's almost always a leaking toilet, and the leakage is often so small as to be invisible.

Yes, you closed the stop-valves, but they sometimes fail (or were never 100%).

Before doing anything drastic, try adding a few drops of food colouring to your toilet cisterns and wait for a couple of hours.

Or even that Blue Block will show a leak in the toilet very well. I've tried it and works fine. HomePro, Thai Watsadoo, Big C or even 7-11 should have it.

[Andrew Dwyer]

4 minutes ago, saengd said:

Yes I agree with the above. If it was me I think I'd probably go with new above surface pipework rather than potentially rip up the whole house trying to find that leak, you can box it in place, paint it, hide it or always ignore it.

 

Sorry you have to go through all that. 

 

 

Yup, hopefully I can make it somewhat unnoticeable.

The kitchen is simple as the 1 water point ( sink ) is on an outside wall and behind an “L” shape worktop so I have options where to come in.

 The 3 bathrooms, on the other hand are more complex, while shower/toilet and sink are in the same plane non of these are on outside walls and the sinks are approximately 2 metres from said outside wall !!

[Andrew Dwyer]

13 minutes ago, ravip said:

Or even that Blue Block will show a leak in the toilet very well. I've tried it and works fine. HomePro, Thai Watsadoo, Big C or even 7-11 should have it.

Yes, I’ve used these in the past and indeed a couple of the toilets still have a faint hint of blue. So will probably try a red food dye instead.

[saengd]

3 minutes ago, Andrew Dwyer said:

Yup, hopefully I can make it somewhat unnoticeable.

The kitchen is simple as the 1 water point ( sink ) is on an outside wall and behind an “L” shape worktop so I have options where to come in.

 The 3 bathrooms, on the other hand are more complex, while shower/toilet and sink are in the same plane non of these are on outside walls and the sinks are approximately 2 metres from said outside wall !!

Can you come in from above?

 

Another option might be a single channel to a central distribution point inside the house that allows you to run new pipe above ground, a combination of in ground and above ground.

[Andrew Dwyer]

1 minute ago, saengd said:

Can you come in from above?

 

Another option might be a single channel to a central distribution point inside the house that allows you to run new pipe above ground, a combination of in ground and above ground.

Was thinking about above already !! although aesthetically more pleasing it would leave a lot of pipework overhead .

Not sure how I feel about that really ?

 

 

[Curt1591]

The agency that supplies your water will locate the leak.