Jump to content
BANGKOK
Andrew Dwyer

Underground water leak - where to start !!

Recommended Posts

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 .

Share this post


Link to post
Share on other sites

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.

  • Like 1

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites

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.  

  • Like 2

Share this post


Link to post
Share on other sites
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.

  • Like 2

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites
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.

 

Share this post


Link to post
Share on other sites
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

  • Like 1

Share this post


Link to post
Share on other sites

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.

  • Like 2

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites
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.

  • Like 2

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites
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 by lopburi3

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...