Finding a water leak - looks like a really tricky one!

[Dave N]

Looks like we could be in just about the worst possible situation for a leak.

We started hearing running water in the cold water feed a couple of days ago, and have confirmed that it's between the stopcock in the street and the one in our house. I've also done a simple leak test dipping the kitchen tap in a glass of water and turning off the stopcock in the street, and you can see the water level in the glass falling quite fast.

The nightmare is that we're in a Victorian terrace with a shared supply that comes through next door and feeds 4 houses from the back, and no one has access to under their kitchen floors. We are in the middle of the line between the feed and one other house. And we've looked under the suspended floor next to the kitchen and confirmed that the floor void has been concreted over rubble, so there's no chance of access from below. And the shared supply means that running a new supply probably isn't feasible either.

Our insurance company isn't interested until we can see visible damage so this isn't covered (yet, anyway). We can only hear the water in our kitchen, not in our neighbours' kitchens so it's likely to be under our property, but we can't be absolutely sure of this.

So...any good suggestions for diagnosing where the leak is, and perhaps persuading our insurance company to do something about it? Thanks :)

[N_Cook]

Post by Dave N
Looks like we could be in just about the worst possible situation for a leak.
We started hearing running water in the cold water feed a couple of days ago, and have confirmed that it's between the stopcock in the street and the one in our house. I've also done a simple leak test dipping the kitchen tap in a glass of water and turning off the stopcock in the street, and you can see the water level in the glass falling quite fast.
The nightmare is that we're in a Victorian terrace with a shared supply that comes through next door and feeds 4 houses from the back, and no one has access to under their kitchen floors. We are in the middle of the line between the feed and one other house. And we've looked under the suspended floor next to the kitchen and confirmed that the floor void has been concreted over rubble, so there's no chance of access from below. And the shared supply means that running a new supply probably isn't feasible either.
Our insurance company isn't interested until we can see visible damage so this isn't covered (yet, anyway). We can only hear the water in our kitchen, not in our neighbours' kitchens so it's likely to be under our property, but we can't be absolutely sure of this.
So...any good suggestions for diagnosing where the leak is, and perhaps persuading our insurance company to do something about it? Thanks :)

Make a listening stick from a steel rod with a large wooden drawer knob
fitted to one end, for placing your ear against.
A skilled human leak detectector can narrow down the disance to the leak
quite closely. The principle is high frequency hiss the leak is near to
you and low pitched rumble is at a distance. How long it takes to gain
the required skill, I don't know.

[Tim Lamb]

Post by Dave N
Looks like we could be in just about the worst possible situation for a leak.
We started hearing running water in the cold water feed a couple of
days ago, and have confirmed that it's between the stopcock in the
street and the one in our house. I've also done a simple leak test
dipping the kitchen tap in a glass of water and turning off the
stopcock in the street, and you can see the water level in the glass
falling quite fast.
The nightmare is that we're in a Victorian terrace with a shared supply
that comes through next door and feeds 4 houses from the back, and no
one has access to under their kitchen floors. We are in the middle of
the line between the feed and one other house. And we've looked under
the suspended floor next to the kitchen and confirmed that the floor
void has been concreted over rubble, so there's no chance of access
from below. And the shared supply means that running a new supply
probably isn't feasible either.
Our insurance company isn't interested until we can see visible damage
so this isn't covered (yet, anyway). We can only hear the water in our
kitchen, not in our neighbours' kitchens so it's likely to be under our
property, but we can't be absolutely sure of this.
So...any good suggestions for diagnosing where the leak is, and perhaps
persuading our insurance company to do something about it? Thanks :)

The water engineers here have used a wooden rod with a cup turned at one
end to listen for the leak. I don't know if the microphone on a mobile
phone could be utilised.

[Dave N]

Thanks for the suggestions - yes, was looking at making a listening stick and that looks like a good starting point. Any more suggestions for tracing the pipework would be welcome. the other thing I'm trying to find out is where the rising main is in each of our neighbours' kitchens, but two if them are away this weekend so I'll have to wait. Ours and next door on one side are both against the rear wall of the kitchen extension and if the other two are as well that would give a starting point as to where the shared pipe is likely to run. However, a neighbour further down the terrace has her rising main further into the extension, and two friends in a nearby terrace have theirs near the back of the main part of the house.
At least we aren't on a meter (I think it would be pretty hard to fit one here anyway, although we keep getting letters about installation it never actually happens) and if we got one it would have to be fitted downstream from the leak unless the water company would like to fix it for us. If the pipe does run along the back wall we could possibly access it by removing bricks rather than breaking the floor, which would be less destructive. In any case it would be very helpful to identify where the leak actually is first.
Please do keep the ideas coming!

[N_Cook]

Post by Dave N
Thanks for the suggestions - yes, was looking at making a listening stick and that looks like a good starting point. Any more suggestions for tracing the pipework would be welcome. the other thing I'm trying to find out is where the rising main is in each of our neighbours' kitchens, but two if them are away this weekend so I'll have to wait. Ours and next door on one side are both against the rear wall of the kitchen extension and if the other two are as well that would give a starting point as to where the shared pipe is likely to run. However, a neighbour further down the terrace has her rising main further into the extension, and two friends in a nearby terrace have theirs near the back of the main part of the house.
At least we aren't on a meter (I think it would be pretty hard to fit one here anyway, although we keep getting letters about installation it never actually happens) and if we got one it would have to be fitted downstream from the leak unless the water company would like to fix it for us. If the pipe does run along the back wall we could possibly access it by removing bricks rather than breaking the floor, which would be less destructive. In any case it would be very helpful to identify where the leak actually is first.
Please do keep the ideas coming!

The next tool in the arsenal is freezing.
When you gain access to the pipe at some point midway, to test whether
that point is before or after the leak.
Traditionally freezer solution of crushed ice cubes and salt in a
cutdown plastic milk bottle made into a trough around the pipe.
These days a can of aerosol freezer spray.
When the supply to your house stops, is there still hiss at the test
point or not.
Often these days leaks are due to excessive number of
Asda/Ocado/Prime/UPS vans parking on the pavement, then the leak is
outside your curtillage , so then the utility companies pigeon.

[Paul]

Post by Dave N
Looks like we could be in just about the worst possible situation for a leak.
We started hearing running water in the cold water feed a couple of days ago, and have confirmed that it's between the stopcock in the street and the one in our house. I've also done a simple leak test dipping the kitchen tap in a glass of water and turning off the stopcock in the street, and you can see the water level in the glass falling quite fast.
The nightmare is that we're in a Victorian terrace with a shared supply that comes through next door and feeds 4 houses from the back, and no one has access to under their kitchen floors. We are in the middle of the line between the feed and one other house. And we've looked under the suspended floor next to the kitchen and confirmed that the floor void has been concreted over rubble, so there's no chance of access from below. And the shared supply means that running a new supply probably isn't feasible either.
Our insurance company isn't interested until we can see visible damage so this isn't covered (yet, anyway). We can only hear the water in our kitchen, not in our neighbours' kitchens so it's likely to be under our property, but we can't be absolutely sure of this.
So...any good suggestions for diagnosing where the leak is, and perhaps persuading our insurance company to do something about it? Thanks :)

The water engineers here have used a wooden rod with a cup turned at one end to listen for the leak. I don't know if the microphone on a mobile phone could be utilised.

Our guys have an amplified one, a pickup disc that lays on
the street, and a pair of headphones. That helps cut down
street noise. It's not really all that fancy. The disc is waterproof,
and they like to put it in puddles.

Paul

[Thomas Prufer]

Post by Paul
Our guys have an amplified one, a pickup disc that lays on
the street, and a pair of headphones. That helps cut down
street noise. It's not really all that fancy. The disc is waterproof,
and they like to put it in puddles.

This came up in a German electronics newsgroup: A group of houses was supplied
by a mile or so of plastic pipe, owned by the householders. Leak in the pipe,
under asphalt so not heap to "just dig and make good".

Someone built a ground microphone and got to within feet of the leak.
Electronics were mostly bought, bit of chickenfeed around a bought circuit
board. Microphone was a piezo beeper disc with a weight and a brass pipe
fitting.

Thomas Prufer

[alan_m]

Post by Thomas Prufer

Post by Paul
Our guys have an amplified one, a pickup disc that lays on
the street, and a pair of headphones. That helps cut down
street noise. It's not really all that fancy. The disc is waterproof,
and they like to put it in puddles.

This came up in a German electronics newsgroup: A group of houses was supplied
by a mile or so of plastic pipe, owned by the householders. Leak in the pipe,
under asphalt so not heap to "just dig and make good".
Someone built a ground microphone and got to within feet of the leak.
Electronics were mostly bought, bit of chickenfeed around a bought circuit
board. Microphone was a piezo beeper disc with a weight and a brass pipe
fitting.
http://youtu.be/SifFYeOc7TE
Thomas Prufer

A fiver for a smart phone (hands free) microphone, mount it in something
like a sink plunger to isolate it from background and a free app on the
phone to analyse the audio.

[Thomas Prufer]

Post by alan_m

Post by Thomas Prufer

Post by Paul
Our guys have an amplified one, a pickup disc that lays on
the street, and a pair of headphones. That helps cut down
street noise. It's not really all that fancy. The disc is waterproof,
and they like to put it in puddles.

This came up in a German electronics newsgroup: A group of houses was supplied
by a mile or so of plastic pipe, owned by the householders. Leak in the pipe,
under asphalt so not heap to "just dig and make good".
Someone built a ground microphone and got to within feet of the leak.
Electronics were mostly bought, bit of chickenfeed around a bought circuit
board. Microphone was a piezo beeper disc with a weight and a brass pipe
fitting.
http://youtu.be/SifFYeOc7TE
Thomas Prufer

A fiver for a smart phone (hands free) microphone, mount it in something
like a sink plunger to isolate it from background and a free app on the
phone to analyse the audio.

The guy that built the piezo sensor tried an electret mike first, with
disappointing results.

Thomas Prufer

[N_Cook]

Post by Thomas Prufer

Post by alan_m

Post by Thomas Prufer

Post by Paul
Our guys have an amplified one, a pickup disc that lays on
the street, and a pair of headphones. That helps cut down
street noise. It's not really all that fancy. The disc is waterproof,
and they like to put it in puddles.

This came up in a German electronics newsgroup: A group of houses was supplied
by a mile or so of plastic pipe, owned by the householders. Leak in the pipe,
under asphalt so not heap to "just dig and make good".
Someone built a ground microphone and got to within feet of the leak.
Electronics were mostly bought, bit of chickenfeed around a bought circuit
board. Microphone was a piezo beeper disc with a weight and a brass pipe
fitting.
http://youtu.be/SifFYeOc7TE
Thomas Prufer

A fiver for a smart phone (hands free) microphone, mount it in something
like a sink plunger to isolate it from background and a free app on the
phone to analyse the audio.

The guy that built the piezo sensor tried an electret mike first, with
disappointing results.
Thomas Prufer

A critical point is repeatably consistant acoustic coupling to different
sorts of pipe to then use an audio spectrum analyser app to get some
sort of distance to leak value.

While on this topic. For tracing the path of a pipe that must have been
laid to avoid a tree that had long since gone as in a loop.
I used a low power RF signal generator with output connected to an
exposed length of the known pipe run and tracked with an ordinary AM MW
+LW radio , giving a whine on the speaker.

[Dave N]

Thanks for the suggestions - here's an update...

1. I've made a simple listening stick from a steel stake that we had in our garden and a wooden door knob, and it seems to work. I also tried a small electret microphone on the end of my listening stick, with a laptop and earbuds, but the set-up wasn't sensitive enough to pick up the sound.
2. I still need to go round and see next door where the common pipe appears to come in from the street (they have been away), to attempt to ascertain where the shared pipe runs. My initial listening indicates that it could be about 0.5-1 metre from the main part of the house into the extension, but soundings and looking at their rising main might help.
3. There seems to be a slight increase in volume and pitch of the noise that I hear with my listening stick near the party wall where I think the supply could come in from next door, so there's still a chance that it's next door, but the noise is much louder near the far corner where the rising main comes up in our kitchen so I'd say this area is most likely. But of course exposed pipes and a pipe coming up through the concrete are likely to sound louder anyway so this isn't certain.
4. Our water company's website seems pretty emphatic on where responsibility lies, with clear pictures. In fact it states that if you report a leak on your premises to them they will take enforcement action if you don't fix it, so I'm not sure whether contacting them will help me at all.
5. Our buildings insurance covers trace and access for leaks as well as repair, but they aren't interested in any kind of claim until there's any visible damage.

So it seems we are still on our own here unless we start getting a significant damp problem or subsidence. All I can do is narrow it down as much as I can and presumably eventually work out where the best place will be to break up the floor, paying for a specialist leak investigator if necessary. Not ideal!

[Tim+]

Post by Dave N
Thanks for the suggestions - here's an update...
1. I've made a simple listening stick from a steel stake that we had in
our garden and a wooden door knob, and it seems to work. I also tried a
small electret microphone on the end of my listening stick, with a laptop
and earbuds, but the set-up wasn't sensitive enough to pick up the sound.
2. I still need to go round and see next door where the common pipe
appears to come in from the street (they have been away), to attempt to
ascertain where the shared pipe runs. My initial listening indicates that
it could be about 0.5-1 metre from the main part of the house into the
extension, but soundings and looking at their rising main might help.
3. There seems to be a slight increase in volume and pitch of the noise
that I hear with my listening stick near the party wall where I think the
supply could come in from next door, so there's still a chance that it's
next door, but the noise is much louder near the far corner where the
rising main comes up in our kitchen so I'd say this area is most likely.
But of course exposed pipes and a pipe coming up through the concrete are
likely to sound louder anyway so this isn't certain.
4. Our water company's website seems pretty emphatic on where
responsibility lies, with clear pictures. In fact it states that if you
report a leak on your premises to them they will take enforcement action
if you don't fix it, so I'm not sure whether contacting them will help me at all.
5. Our buildings insurance covers trace and access for leaks as well as
repair, but they aren't interested in any kind of claim until there's any visible damage.
So it seems we are still on our own here unless we start getting a
significant damp problem or subsidence. All I can do is narrow it down as
much as I can and presumably eventually work out where the best place
will be to break up the floor, paying for a specialist leak investigator
if necessary. Not ideal!

If you’ve not noticed a problem up till now it’s probable that the water
has found it’s way into an existing drain. This happened to our neighbours.
Lifting a manhole or two and looking to see where the water is leaving may
help in locating it.

Tim

[Tim+]

Post by Dave N
Thanks for the suggestions - here's an update...
1. I've made a simple listening stick from a steel stake that we had in
our garden and a wooden door knob, and it seems to work. I also tried a
small electret microphone on the end of my listening stick, with a laptop
and earbuds, but the set-up wasn't sensitive enough to pick up the sound.
2. I still need to go round and see next door where the common pipe
appears to come in from the street (they have been away), to attempt to
ascertain where the shared pipe runs. My initial listening indicates that
it could be about 0.5-1 metre from the main part of the house into the
extension, but soundings and looking at their rising main might help.
3. There seems to be a slight increase in volume and pitch of the noise
that I hear with my listening stick near the party wall where I think the
supply could come in from next door, so there's still a chance that it's
next door, but the noise is much louder near the far corner where the
rising main comes up in our kitchen so I'd say this area is most likely.
But of course exposed pipes and a pipe coming up through the concrete are
likely to sound louder anyway so this isn't certain.
4. Our water company's website seems pretty emphatic on where
responsibility lies, with clear pictures. In fact it states that if you
report a leak on your premises to them they will take enforcement action
if you don't fix it, so I'm not sure whether contacting them will help me at all.
5. Our buildings insurance covers trace and access for leaks as well as
repair, but they aren't interested in any kind of claim until there's any visible damage.
So it seems we are still on our own here unless we start getting a
significant damp problem or subsidence. All I can do is narrow it down as
much as I can and presumably eventually work out where the best place
will be to break up the floor, paying for a specialist leak investigator
if necessary. Not ideal!

How’s this for a bit of lateral thinking, apply for a water meter. This way
the water company will be obliged to give you an individual supply. ;-)

Tim

[John Walliker]

Post by Tim+

Post by Dave N
Thanks for the suggestions - here's an update...
1. I've made a simple listening stick from a steel stake that we had in
our garden and a wooden door knob, and it seems to work. I also tried a
small electret microphone on the end of my listening stick, with a laptop
and earbuds, but the set-up wasn't sensitive enough to pick up the sound.
2. I still need to go round and see next door where the common pipe
appears to come in from the street (they have been away), to attempt to
ascertain where the shared pipe runs. My initial listening indicates that
it could be about 0.5-1 metre from the main part of the house into the
extension, but soundings and looking at their rising main might help.
3. There seems to be a slight increase in volume and pitch of the noise
that I hear with my listening stick near the party wall where I think the
supply could come in from next door, so there's still a chance that it's
next door, but the noise is much louder near the far corner where the
rising main comes up in our kitchen so I'd say this area is most likely.
But of course exposed pipes and a pipe coming up through the concrete are
likely to sound louder anyway so this isn't certain.
4. Our water company's website seems pretty emphatic on where
responsibility lies, with clear pictures. In fact it states that if you
report a leak on your premises to them they will take enforcement action
if you don't fix it, so I'm not sure whether contacting them will help me at all.
5. Our buildings insurance covers trace and access for leaks as well as
repair, but they aren't interested in any kind of claim until there's any visible damage.
So it seems we are still on our own here unless we start getting a
significant damp problem or subsidence. All I can do is narrow it down as
much as I can and presumably eventually work out where the best place
will be to break up the floor, paying for a specialist leak investigator
if necessary. Not ideal!

How’s this for a bit of lateral thinking, apply for a water meter. This way
the water company will be obliged to give you an individual supply. ;-)
Tim

My experience with water companies has been very positive. I had
multiple leaks in the service pipe due to sharp rock fragments cutting into it.
The inspector came and the company fixed the leaks several times, even though
they were strictly our responsibility. The cost of the losses was rebated. One leak
happened when there was nobody at the property and 19000 m^3 were lost in
three weeks with no water visible at the surface.
The flow was so great that the water meter under the pavement could be heard rattling
from 10m away. This time the inspector suggested that perhaps we should do
something to improve the situation , so we had the service pipe replaced and made
sure it was completely enclosed in flexible trunking for extra protection. It cost
about £1k because the excavator had to work very hard in all the rock and it took
a day to dig the new trench.
John

[NY]

Post by Tim+
How’s this for a bit of lateral thinking, apply for a water meter. This way
the water company will be obliged to give you an individual supply. ;-)

Our last house had a communal feed from a stop tap under the pavement, to
three houses in a terrace - and maybe to the next 3-house terrace as well.

When we asked about getting a water meter, the answer was "you can't have
one" rather than "we will need to run a separate feed from the pipe in the
road" - in other words "it's too difficult".

Silly question: why does a single pipe that branches to several houses not
allow separate meters as long as they are after the branching point and are
therefore only measuring the water that is used by one house?

[Fredxx]

Post by NY

Post by Tim+
How’s this for a bit of lateral thinking, apply for a water meter. This way
the water company will be obliged to give you an individual supply. ;-)

Our last house had a communal feed from a stop tap under the pavement,
to three houses in a terrace - and maybe to the next 3-house terrace as
well.
When we asked about getting a water meter, the answer was "you can't
have one" rather than "we will need to run a separate feed from the pipe
in the road" - in other words "it's too difficult".
Silly question: why does a single pipe that branches to several houses
not allow separate meters as long as they are after the branching point
and are therefore only measuring the water that is used by one house?

I've come across many meters that are in the house but readable outside
via a transducer.

[Tricky Dicky]

Post by NY

Post by Tim+
How’s this for a bit of lateral thinking, apply for a water meter. This way
the water company will be obliged to give you an individual supply. ;-)

Our last house had a communal feed from a stop tap under the pavement, to
three houses in a terrace - and maybe to the next 3-house terrace as well.
When we asked about getting a water meter, the answer was "you can't have
one" rather than "we will need to run a separate feed from the pipe in the
road" - in other words "it's too difficult".
Silly question: why does a single pipe that branches to several houses not
allow separate meters as long as they are after the branching point and are
therefore only measuring the water that is used by one house?

At our last house we shared a supply with next door and when we asked about
a water meter they likewise said they could not do it. Instead they put us
on a rate that they expected that a house of our size and number of
occupants would end up paying with a meter which worked out less than the
rate based on the rateable value .

[Thomas Prufer]

Post by N_Cook
A critical point is repeatably consistant acoustic coupling to different
sorts of pipe to then use an audio spectrum analyser app to get some
sort of distance to leak value.

The guy that built the piezo setup posted in de.sci.elctronics:

The pros had failed to find the leak using two microphones and a correlation
setup, on a run of 150 meters under asphalt in 40 mm plastic pipe.

He's flown a drone over the run, on the chance that the plants might be visibly
greener (in a hot summer) near the leak.

Post by N_Cook
While on this topic. For tracing the path of a pipe that must have been
laid to avoid a tree that had long since gone as in a loop.
I used a low power RF signal generator with output connected to an
exposed length of the known pipe run and tracked with an ordinary AM MW
+LW radio , giving a whine on the speaker.

Other suggestions for the scenario that led to the piezo setup (where Rf
wouldn't work -- plastic pipe) were:

- take resistance measurements between the water in the pipe and the ground,
along the presumed pipe run -- nearer the leak should show lower resistance.
- blow helium in the pipe and use a helium detector
- blow compressed air in the pipe and use a microphone/listening stick as the
leak would be/might be louder
- dig up the middle, install a valve, and see if the leak is before or after,
repeat.

Thomas Prufer

[N_Cook]

Post by Thomas Prufer

Post by N_Cook
A critical point is repeatably consistant acoustic coupling to different
sorts of pipe to then use an audio spectrum analyser app to get some
sort of distance to leak value.

The pros had failed to find the leak using two microphones and a correlation
setup, on a run of 150 meters under asphalt in 40 mm plastic pipe.
He's flown a drone over the run, on the chance that the plants might be visibly
greener (in a hot summer) near the leak.

Post by N_Cook
While on this topic. For tracing the path of a pipe that must have been
laid to avoid a tree that had long since gone as in a loop.
I used a low power RF signal generator with output connected to an
exposed length of the known pipe run and tracked with an ordinary AM MW
+LW radio , giving a whine on the speaker.

Other suggestions for the scenario that led to the piezo setup (where Rf
- take resistance measurements between the water in the pipe and the ground,
along the presumed pipe run -- nearer the leak should show lower resistance.
- blow helium in the pipe and use a helium detector
- blow compressed air in the pipe and use a microphone/listening stick as the
leak would be/might be louder
- dig up the middle, install a valve, and see if the leak is before or after,
repeat.
Thomas Prufer

Then there is water diving, just needs a couple of bent bicycle spokes
in some bits of bio pen, worth a try.

[SH]

Post by N_Cook

Post by Thomas Prufer

Post by N_Cook
A critical point is repeatably consistant acoustic coupling to different
sorts of pipe to then use an audio spectrum analyser app to get some
sort of distance to leak value.

The pros had failed to find the leak using two microphones and a correlation
setup, on a run of 150 meters under asphalt in 40 mm plastic pipe.
He's flown a drone over the run, on the chance that the plants might be visibly
greener (in a hot summer) near the leak.

Post by N_Cook
While on this topic. For tracing the path of a pipe that must have been
laid to avoid a tree that had long since gone as in a loop.
I used a low power RF signal generator with output connected to an
exposed length of the known pipe run and tracked with an ordinary AM MW
+LW radio , giving a whine on the speaker.

Other suggestions for the scenario that led to the piezo setup (where Rf
- take resistance measurements between the water in the pipe and the ground,
along the presumed pipe run -- nearer the leak should show lower resistance.
- blow helium in the pipe and use a helium detector
- blow compressed air in the pipe and use a microphone/listening stick as the
leak would be/might be louder
- dig up the middle, install a valve, and see if the leak is before or after,
repeat.
Thomas Prufer

Then there is water diving, just needs a couple of bent bicycle spokes
in some bits of bio pen, worth a try.

Think you might break your neck diving into the ground towards the water
sodden area underground...... :-D

[Harry Bloomfield Esq]

Post by Thomas Prufer
http://youtu.be/SifFYeOc7TE

Clever idea, but I would want to add a meter to it, for a better
indication of noise level.

[Harry Bloomfield Esq]

Post by Tim Lamb
The water engineers here have used a wooden rod with a cup turned at one
end to listen for the leak. I don't know if the microphone on a mobile
phone could be utilised.

The mic on a phone seems ideal, they are tiny, better suited to high
frequencies. There are plenty of apps, able to show the waveform on screen.

A diaphram, with a weight (as per the German vid), with a pipe to
transmit the noise up to the phone.

[Robin]

Post by Dave N
Looks like we could be in just about the worst possible situation for a leak.
We started hearing running water in the cold water feed a couple of days ago, and have confirmed that it's between the stopcock in the street and the one in our house. I've also done a simple leak test dipping the kitchen tap in a glass of water and turning off the stopcock in the street, and you can see the water level in the glass falling quite fast.
The nightmare is that we're in a Victorian terrace with a shared supply that comes through next door and feeds 4 houses from the back, and no one has access to under their kitchen floors. We are in the middle of the line between the feed and one other house. And we've looked under the suspended floor next to the kitchen and confirmed that the floor void has been concreted over rubble, so there's no chance of access from below. And the shared supply means that running a new supply probably isn't feasible either.
Our insurance company isn't interested until we can see visible damage so this isn't covered (yet, anyway). We can only hear the water in our kitchen, not in our neighbours' kitchens so it's likely to be under our property, but we can't be absolutely sure of this.
So...any good suggestions for diagnosing where the leak is, and perhaps persuading our insurance company to do something about it? Thanks :)

Check with your water company. Your and your neighbours are responsible
for the supply pipe. But the supplier may be able to help. At the very
least they may help persuade your neighbours it's their problem too.

[Davidm]

On Fri, 10 Nov 2023 10:31:11 -0800 (PST), Dave N

Post by Dave N
Looks like we could be in just about the worst possible situation for a leak.
We started hearing running water in the cold water feed a couple of days ago, and have confirmed that it's between the stopcock in the street and the one in our house. I've also done a simple leak test dipping the kitchen tap in a glass of water and turning off the stopcock in the street, and you can see the water level in the glass falling quite fast.
The nightmare is that we're in a Victorian terrace with a shared supply that comes through next door and feeds 4 houses from the back, and no one has access to under their kitchen floors. We are in the middle of the line between the feed and one other house. And we've looked under the suspended floor next to the kitchen and confirmed that the floor void has been concreted over rubble, so there's no chance of access from below. And the shared supply means that running a new supply probably isn't feasible either.
Our insurance company isn't interested until we can see visible damage so this isn't covered (yet, anyway). We can only hear the water in our kitchen, not in our neighbours' kitchens so it's likely to be under our property, but we can't be absolutely sure of this.
So...any good suggestions for diagnosing where the leak is, and perhaps persuading our insurance company to do something about it? Thanks :)

As the leak is after the street stopcock your water company is not
responsible for it, but they might (should) have an interest in
conserving water and might send someone out to help identify where the
leak is. Worth asking them. It worked for me a few years ago. The
engineer they sent out not only found where the leak was but put me in
touch with some guys who came out and fixed it (new pipe). Cash in
hand job, they were contractors who were used by the water company, so
had all the right equipment.

[Tricky Dicky]

Post by Davidm
On Fri, 10 Nov 2023 10:31:11 -0800 (PST), Dave N

Post by Dave N
Looks like we could be in just about the worst possible situation for a leak.
We started hearing running water in the cold water feed a couple of days
ago, and have confirmed that it's between the stopcock in the street and
the one in our house. I've also done a simple leak test dipping the
kitchen tap in a glass of water and turning off the stopcock in the
street, and you can see the water level in the glass falling quite fast.
The nightmare is that we're in a Victorian terrace with a shared supply
that comes through next door and feeds 4 houses from the back, and no
one has access to under their kitchen floors. We are in the middle of
the line between the feed and one other house. And we've looked under
the suspended floor next to the kitchen and confirmed that the floor
void has been concreted over rubble, so there's no chance of access from
below. And the shared supply means that running a new supply probably
isn't feasible either.
Our insurance company isn't interested until we can see visible damage
so this isn't covered (yet, anyway). We can only hear the water in our
kitchen, not in our neighbours' kitchens so it's likely to be under our
property, but we can't be absolutely sure of this.
So...any good suggestions for diagnosing where the leak is, and perhaps
persuading our insurance company to do something about it? Thanks :)

As the leak is after the street stopcock your water company is not
responsible for it, but they might (should) have an interest in
conserving water and might send someone out to help identify where the
leak is. Worth asking them. It worked for me a few years ago. The
engineer they sent out not only found where the leak was but put me in
touch with some guys who came out and fixed it (new pipe). Cash in
hand job, they were contractors who were used by the water company, so
had all the right equipment.

Where several properties share the same sewer pipe then the water company
is responsible for the sewers to each property, is this not the same for
the water supply? If it is the residents responsibility then as you all
share the same supply I would imagine it is everybody’s responsibility to
fix it, particularly those past your property as their supply would be
affected by the leak on your property.

[Robin]

Post by Tricky Dicky

Post by Davidm
On Fri, 10 Nov 2023 10:31:11 -0800 (PST), Dave N

Post by Dave N
Looks like we could be in just about the worst possible situation for a leak.
We started hearing running water in the cold water feed a couple of days
ago, and have confirmed that it's between the stopcock in the street and
the one in our house. I've also done a simple leak test dipping the
kitchen tap in a glass of water and turning off the stopcock in the
street, and you can see the water level in the glass falling quite fast.
The nightmare is that we're in a Victorian terrace with a shared supply
that comes through next door and feeds 4 houses from the back, and no
one has access to under their kitchen floors. We are in the middle of
the line between the feed and one other house. And we've looked under
the suspended floor next to the kitchen and confirmed that the floor
void has been concreted over rubble, so there's no chance of access from
below. And the shared supply means that running a new supply probably
isn't feasible either.
Our insurance company isn't interested until we can see visible damage
so this isn't covered (yet, anyway). We can only hear the water in our
kitchen, not in our neighbours' kitchens so it's likely to be under our
property, but we can't be absolutely sure of this.
So...any good suggestions for diagnosing where the leak is, and perhaps
persuading our insurance company to do something about it? Thanks :)

As the leak is after the street stopcock your water company is not
responsible for it, but they might (should) have an interest in
conserving water and might send someone out to help identify where the
leak is. Worth asking them. It worked for me a few years ago. The
engineer they sent out not only found where the leak was but put me in
touch with some guys who came out and fixed it (new pipe). Cash in
hand job, they were contractors who were used by the water company, so
had all the right equipment.

Where several properties share the same sewer pipe then the water company
is responsible for the sewers to each property, is this not the same for
the water supply?

No.

If it is the residents responsibility then as you all

Post by Tricky Dicky
share the same supply I would imagine it is everybody’s responsibility to
fix it, particularly those past your property as their supply would be
affected by the leak on your property.

It is a joint responsibility (subject I think to anything in the deeds)
but getting everyone to pay is not always easy. One benefit of getting
the supplier to do the job (if they offer that option) is that they may
(a) require everyone to sign up to pay their share and (b) take on the
job of chasing for payments. Depending on your neighbours that can be
well worth a higher price than cash-in-hand contractors.

[n***@aolbin.com]

Post by Dave N
Looks like we could be in just about the worst possible situation for a leak.
We started hearing running water in the cold water feed a couple of days ago, and have confirmed that it's between the stopcock in the street and the one in our house. I've also done a simple leak test dipping the kitchen tap in a glass of water and turning off the stopcock in the street, and you can see the water level in the glass falling quite fast.
The nightmare is that we're in a Victorian terrace with a shared supply that comes through next door and feeds 4 houses from the back, and no one has access to under their kitchen floors. We are in the middle of the line between the feed and one other house. And we've looked under the suspended floor next to the kitchen and confirmed that the floor void has been concreted over rubble, so there's no chance of access from below. And the shared supply means that running a new supply probably isn't feasible either.
Our insurance company isn't interested until we can see visible damage so this isn't covered (yet, anyway). We can only hear the water in our kitchen, not in our neighbours' kitchens so it's likely to be under our property, but we can't be absolutely sure of this.
So...any good suggestions for diagnosing where the leak is, and perhaps persuading our insurance company to do something about it? Thanks :)

Report it to the water company who will check and confirm the leak. They
should also base water charges on usage that existed before the leak was
reported, so you won't pay for the lost water. Some companies will
repair one leak FOC so speak to them and apply a bit of persuasion. I
managed to get my water company to repair a leak in the supply pipe but
a year or so later decided to pay for a new pipe to be mole'd in when it
failed again.

[Animal]

Post by Dave N
Looks like we could be in just about the worst possible situation for a leak.
We started hearing running water in the cold water feed a couple of days ago, and have confirmed that it's between the stopcock in the street and the one in our house. I've also done a simple leak test dipping the kitchen tap in a glass of water and turning off the stopcock in the street, and you can see the water level in the glass falling quite fast.
The nightmare is that we're in a Victorian terrace with a shared supply that comes through next door and feeds 4 houses from the back, and no one has access to under their kitchen floors. We are in the middle of the line between the feed and one other house. And we've looked under the suspended floor next to the kitchen and confirmed that the floor void has been concreted over rubble, so there's no chance of access from below. And the shared supply means that running a new supply probably isn't feasible either.
Our insurance company isn't interested until we can see visible damage so this isn't covered (yet, anyway). We can only hear the water in our kitchen, not in our neighbours' kitchens so it's likely to be under our property, but we can't be absolutely sure of this.
So...any good suggestions for diagnosing where the leak is, and perhaps persuading our insurance company to do something about it? Thanks :)

I'm not sure why you want to find the leak in a rotten pipe you can't access. Replacement would make more sense.

[DaveN]

Well it's a few months on and here's an update...

In the end we found that there was little chance of pinpointing the leak
ourselves, and next door (where the supply comes in from the street)
eventually decided to get a plumber in, who did a lot of listening and
used a 'damp meter' (technology unknown). He eventually concluded that
there was more than one leak in the system, probably at least under our
solid floor kitchen and under the house on the other side. He couldn't
get into the fourth house but suspected that there might be a further
leak there too.

So in the end the obvious solution is to replace the supply to all 4
houses. The initial quote from the company that detected the leaks was
about £1300 per house, but I thought there must be a cheaper way that
involved minimal digging and running the shared supply through the voids
under the main part of our houses (rather than the kitchen extensions,
two of which have concrete floors). I found a local Thames Water
recommended plumber who thinks he can do the job for around £400 per
house - in our house there will be a small amount of surface pipework in
the kitchen, and two of the houses still have voids under their kitchen
extensions so will be simple to do. At that price all the neighbours are
happy, so when we can finally arrange for us all not to be away we hope
to get it all fixed - hopefully in 2-3 weeks.

[N_Cook]

Post by DaveN
Well it's a few months on and here's an update...
In the end we found that there was little chance of pinpointing the leak
ourselves, and next door (where the supply comes in from the street)
eventually decided to get a plumber in, who did a lot of listening and
used a 'damp meter' (technology unknown). He eventually concluded that
there was more than one leak in the system, probably at least under our
solid floor kitchen and under the house on the other side. He couldn't
get into the fourth house but suspected that there might be a further
leak there too.
So in the end the obvious solution is to replace the supply to all 4
houses. The initial quote from the company that detected the leaks was
about £1300 per house, but I thought there must be a cheaper way that
involved minimal digging and running the shared supply through the voids
under the main part of our houses (rather than the kitchen extensions,
two of which have concrete floors). I found a local Thames Water
recommended plumber who thinks he can do the job for around £400 per
house - in our house there will be a small amount of surface pipework in
the kitchen, and two of the houses still have voids under their kitchen
extensions so will be simple to do. At that price all the neighbours are
happy, so when we can finally arrange for us all not to be away we hope
to get it all fixed - hopefully in 2-3 weeks.

Any opinion ventured to the cause of the leaks?
Say, water hammer/vibration of the pipe against flint or stones or at
brick edges of sleeper walls etc

[alan_m]

Post by N_Cook
Any opinion ventured to the cause of the leaks?
Say, water hammer/vibration of the pipe against flint or stones or at
brick edges of sleeper walls etc

When was the pipe installed?

There was a lot of dodgy copper pipe around in the 1970s and early 1980s.

A few years back I had a leak in pipe installed around that time. I
could hear a faint hiss from a pipe under the floorboards. On lifting
the floor boards I found a length of pipe with a pin-hole leak. The area
around the leak had gone rusty - a contamination by another metal in a
copper pipe. I replaced the complete length under the floorboard.

I was lucky that the leak was on the ground floor and in the void
between the concrete slab and my floorboards. The area was very wet
indicating a leak for a some time but the leak was exiting downwards
towards the concrete and not upwards to the carpeted floorboards.