UKC

After the cold snap I got back to the house to a clicking noise which turned out to be the water meter recording about 1l a sec.  I assumed a burst pipe and huge flood somewhere but...there is nothing.  Any ideas what could be going on?  I have investigated all the pipework I can see which seems fine, taps etc work with apparently normal pressure.  No water in the house, no overflow running, no damp areas outside, heat works fine. Rather puzzled.  Water currently turned off.

It stops when you turn the water off but comes back when you turn it on? It's got to be a leak somewhere!

Where is it turned off? Stop-tap at meter or in the house? I guess you can eliminate different sections of pipes if they've got isolation valves between them but if it's something in the house then it should be pretty obvious.

We had a leak too after the cold snap but it was pretty obvious, an end-cap popped off an old pipe, luckily we were in the house and it was during the day.

Yes!  But must be either a leak directly into a drain, so it doesn't show up, or perhaps under a floor somewhere I can't see  - I am beginning to suspect the line to an outside tap that appears to be buried in a wall for 2-3m.

House-side of the water meter, so it's somewhere in the house plumbing, of which there isn't much, really.

Somewhere under a suspended floor perhaps, if it's spraying down at that rate it'll quite possibly just be soaking away until the previously dry ground saturates. You should be able to hear that kind of flow when the house is quiet.

If it's not a leak into the house it's got to be going through a plumbed-to-the-drain overflow so toilet, boiler, washing machine etc. Pop the inspection cover on your drain, see if it's flowing there.

Is your central heating working? If the fill valve is open (it shouldn't be) water can get into the heating loop and from there out via a leak or the pressure relief valve. If town pressure is up to keep leaky pipes flowing water the relief may have popped open. One of my rads sprung a leak during the cold, mostly I think because I was using my knackered boiler more and the pressure is all over the place.

Another possibility is it was something like the dishwasher filling and you happened to hear it, put 2 and 2 together with the cold and assumed a leak. Turn it back on for a minute and check again?

Is there any outdoor plumbing in the garden you've forgotten about?

jk

many modern toilets have the overflow going into the pan rather than an overflow pipe, perhaps worth a look

outside taps ‘should’ have a gate valve inside the house so you can turn off the outside supply during cold snaps. If you have one on your outside tap you can close it off and find/disregard another leak source 

outside taps ‘should’ have a gate valve inside the house so you can turn off the outside supply during cold snaps. If you have one on your outside tap you can close it off and find/disregard another leak source 

It could also be a faulty meter

As above, modern toilets usually overflow straight into the pan and the running water can be difficult to see. Hold a wad of bog paper against the back of the pan and it will quickly become soaked if there's water running down.

Geberit flush mechanisms have a fault where the soft silicon washer on the main release valve becomes blistered with little pockets of water and allows water to flow into the pan. This one baffled us for six months before I worked out what was happening.  

But a litre a second is a big leak, try pressing the tip of a screwdriver or dowel against the incoming main, pressing the handle into your ear and listening for the sound of running water, it's what the water board will do when you report a leak.

Thanks (and to other posters).  A few things to try later on!

Buy a cheap stethoscope and you can hear if there is water running through pipes. The louder it is the closer you are to your leak. 

Given the severity of the weather, don't ignore the possibility of multiple small leaks rather than one big one.

Buy a stethoscope? Why waste the money? As I wrote, the first thing the engineer will do will be to place a metal rod on the pipe, stick the other end in an ear and listen for the hiss of escaping water. Anyway a stethoscope is designed for listening to the insides of people's bodies and won't work too well on a hard, curved surface.

Should.... It appears not, or if there is it will involve dismantling the kitchen!

is that an exaggeration? 60l/min would be faster than a 15mm tap left on, it's a huge flow rate much more than a burst joint etc.

Upstairs leaking that fast would show in the ceiling quite quickly, I'd have thought.

If you throttle the top cock can you affect the flow rate? If not then maybe it's your meter but it would be a big coincidence for the meter to go after a freeze.

At 60l/min though you could just feel the pipe probably and sense a flow.

if you haven't got them already buy some isolator valves ready for when you find it (or if you don't!) then you can at least get the water back on.

What flow rate is the meter showing when you open a tap or two?

I haven't timed it but its of that order, which I agree is alarming!!  Also puzzling as you say

I'll try.

It doesn't seem to alter much - that is, leak rate =leak plus tap on rate

I haven't got one but all the water meters I've seen are mechanical, I can see how a knackered one could maybe flow but not count or under-count flow but there's no way they can spin over when there isn't a flow.

MG: are you terraced/semi detached, could there have been some cross connection into a neighbour's house or garden for whatever reason in the past?

jk

If it's any consolation you're making the HMS Queen Elizabeth look positively watertight with that magnitude of leak.

I remember now that my Mum had this at her cottage in Wiltshire, which stands on gravel. She lives alone but received a water bill for £440, which almost gave her a heart attack. There was no sign of a leak. After some days Bournemouth Water came out, the engineer stuck his sounding rod on her main near the meter and said: "Yeah, it's a big leak" then went away. Nobody seemed to care except my elderly Mum who was freaking out about the size of the water bill. After a couple of weeks a crew arrived and dug up the main, which had broken near the meter. They repaired it and filled in the hole - only to find that water was still escaping. So two weeks later another crew came, dug it all up again and found two more leaks further downstream. In fixing those they damaged her rising gas main, also a fragile old pipe, meaning the gas board had to come and dig that out, under the wall and replace it right up to her meter. 

My mum was an absolute bundle of nerves so I rang Bournemouth Water who blandly assured me that under the contract she is allowed one leak in any five-year period and she wouldn't have to pay any extra. She received a new bill at the regular amount and paid it then tootled off to find something else to worry about. Today it's the poisoned Russian in Salisbury, who she thinks may have contaminated her.

I'd try:-

Turn stop tap off in house, inspect meter, is it still passing water?

Turn stop tap off at meter and check flow stops.

Has the water pressure in the house drop significantly?

As has been said 60l/min is quite a flow, our bog, which has a rapid fill takes about 13.5l in 30 seconds so 27l/min. We have high water pressure here too.

You can buy a stethoscope for £2.86. Hardly going to break the bank. A screwdriver also works. 

Thanks for explaining what a stethoscope is for. I had no idea.

Apart from the ones that are intended for listening to machines, which will work perfectly well on a hard, curved surface.  Eg: Fleabay item number 151664886433

You sure it isn't 0.1L /s. How many decimal places on your meter?

1L /second and you'll have used a years water in 24 hours. At £300-400 / day you'd better get someone in soonish.

Three, so I make the last 1/1000m^3=1L

Yes...

If it turns out to be a faulty meter somehow, it may be useful to have a record of what the meter reading was on certain days so they can work back and not charge you excessively. Not sure if that's how it works, but I'd be writing down a few numbers to cover my backside.

To add, it does appear a years supply has disappeared in two days. Where the £&*#*#&is it going!!

Plumber called. All the good suggestions above haven’t identified the problem.

From when you started this thread, that's 41,500 litres gone somewhere!

That's one of these full: http://www.halgan.com.au/wp-content/uploads/RWIGR-3.pdf

WTF

Right, solved, sort of.

Turning off the dish washer feed (I have literally never used this) stops the flow. This is straight off the main, which explains the flow rate.   Still haven’t figured out where it was going. Straight to drain, I think, given no flood. Somehow.

Someone suggested to check your drains hours ago!
You're going to have turn your meter around now to rewind it a bit

It's going to the next sink hole......., I say in jest.

Not that easy...

All you need is a pipe freezer kit ...

If I was naughty, there is actually room to bypass the meter altogether!

Do you live next to Birdie Num Num?

This thread has been fascinating, the number of things to think about investigating.

In case anyone's interested, the dishwasher wasn't the culprit.  The blue (dishwasher style) hose was in fact connected to a feed to an outside tap(!) that runs though a cavity wall for several metres.  It appears this feed burst within the wall, which is presumably now full of water...  However the line is now capped.

Don't worry, the water won't have soaked the walls, it will have run down and washed away your foundations. You'd better remove all your possessions from that part of the house before it goes down a huge sinkhole.