Stopcock not turning off all water to house - pipe leaking underfloor

[Anp]

I’m looking for a bit of advice as I’ve just had a plumber around so wanted to see if his theory matches others.
I’ve just inherited a house so wanted to start renovations, when I went to pull up utility tiles noticed they had started coming up..remove them and there is a stretch of cement that is damp to the touch. All the pipes in this house are buried under cement! Called a plumber out to see what the problem is...
He turned off the stopcock and all water stops to the house except for the downstairs toilet, you can hear it clear as day. The water is exceptionally slow to fill on the toilet also, but there is no isolation to turn the water off to it? The plumbers theory is the mains water supply has been split in two, one that allows water to the rest of the house which can be turned off, and the other which is a constant flow to the toilet and that lead pipe now has a leak? I find it hard to understand how the pipe can’t be turned off? Am I missing something? Thanks

 

[Aquarius]

It’s possible that the main was split, or if an old outhouse was converted to now be inside?

 

[Chuck]

It's most likely that your plumber is correct. Professional plumbers don't usually get this stuff wrong. But just in case they were having a bad day or you want to understand their reasoning better...

Does the toilet stop filling if the water company's stopcock, which will be buried at the property boundary is turned off?

Do you have a water meter, if so does it indicate consumption while the toilet is filling but the household stopcock is off?

Have you checked for a storage tank somewhere that could supplying the toilet? What type of hot water system do you have?

 

[Anp]

It’s possible that the main was split, or if an old outhouse was converted to now be inside?

Thanks for replying, yes we thought it may of previously been an outbuilding. Would the repair be something along the lines of.. dig up the floor, fix the leak..add a stopcock to that pipe also? Seems easiest way if it is that!
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It's most likely that your plumber is correct. Professional plumbers don't usually get this stuff wrong. But just in case they were having a bad day or you want to understand their reasoning better...

Does the toilet stop filling if the water company's stopcock, which will be buried at the property boundary is turned off?

Do you have a water meter, if so does it indicate consumption while the toilet is filling but the household stopcock is off?

Have you checked for a storage tank somewhere that could supplying the toilet? What type of hot water system do you have?

The toilet does stop filling when it’s turned off outside from the main water supply just not the internal one. I have no water meter at the house. The plumber didn’t mention anything about a storage tank but that’s a good idea I will check tomorrow when I’m up there. The house has a combi boiler. Thanks for replying it’s very stressful!

 

[Bertharius]

I’m looking for a bit of advice as I’ve just had a plumber around so wanted to see if his theory matches others.
I’ve just inherited a house so wanted to start renovations, when I went to pull up utility tiles noticed they had started coming up..remove them and there is a stretch of cement that is damp to the touch. All the pipes in this house are buried under cement! Called a plumber out to see what the problem is...
He turned off the stopcock and all water stops to the house except for the downstairs toilet, you can hear it clear as day. The water is exceptionally slow to fill on the toilet also, but there is no isolation to turn the water off to it? The plumbers theory is the mains water supply has been split in two, one that allows water to the rest of the house which can be turned off, and the other which is a constant flow to the toilet and that lead pipe now has a leak? I find it hard to understand how the pipe can’t be turned off? Am I missing something? Thanks

I used to live in a Victorian house that had two water supplies from the street - both made of lead - one to the kitchen and one to the bathroom. The one to the bathroom had no stopcock so it looks like you've got the same problem - with the further downside of a slow supply/leak.
Replace the lead pipes (there might be a council grant for this) and have new stopcock fitted.

 

[Anp]

I used to live in a Victorian house that had two water supplies from the street - both made of lead - one to the kitchen and one to the bathroom. The one to the bathroom had no stopcock so it looks like you've got the same problem - with the further downside of a slow supply/leak.
Replace the lead pipes (there might be a council grant for this) and have new stopcock fitted.

Thanks for replying, I have a different plumber coming out as no one else is interested in doing it, I’ll ask him to replace the pipes like you said and I’ll have a look if there is a grant! Thanks 😊

 

[Chuck]

The toilet does stop filling when it’s turned off outside from the main water supply just not the internal one. I have no water meter at the house. The plumber didn’t mention anything about a storage tank but that’s a good idea I will check tomorrow when I’m up there.

If the toilet stops filling when the external stopcock is shut, the toilet must be taken off your service pipe before your internal stopcock and my tank(s) hypothesis can be ruled out.

The solution to this sort of problem is going to be site-specific. With the right equipment it's possible to detect and trace pipes buried in concrete and identify the location of a leak. Not many plumbers are set up for this so you may want to get a quote fron a 'leak finding' company.

Don't jump to the conclusion that your damp patch is a leak in your pipe untill you've ruled out other causes, such as a broken damp proof membrane or condensation.

 

[Ben-gee]

Often in this scenario; rather than dig up concrete and repair a failing pipe - abandon this pipe and run in a new service , keeping it surface within the property. I have done this many times, it is less disruptive and more reliable....