Finding a Water Leak

WIAWSNB

Jumper55 said:

Thanks for all your comments and suggestions.
For information and to answer some of the questions.  It is a 3 storey townhouse.  The main stopcock is on the ground floor in the integrated garage.  There is the washing machine and a toilet/sink on that floor.
The kitchen is on the first floor and the boiler is in the kitchen.
On the second floor is the main bathroom and an ensuite.  There is also the airing cupboard with the hot water tank.
In the loft is the cold water tank.  Someone mentioned an F&E tank - sorry I dont know what that is?
I will do some more tests at the weekend and get up in the loft to see if I can see anything amiss there.
However, as was mentioned, with nearly double my normal usage it would be a lot of water and very surprising that I cant see any sign of it at all.
It leads me to think that a faulty meter is more likely.  If thats the case do I just phone my water company to get them to come and test it?
Thanks again for your responses.

From your description, I would imagine that all the H and C water supplies are run internally within the fabric - skin - of the house, so any leak there would almost certainly be very obvious.

Can you trace where the incoming cold mains supply goes after the garage stopcock? Follow its path until it disappears through a wall or ceiling, and then try and pick it up where it might emerge! The cold mains will certainly be heading directly to the kitchen sink to provide fresh mains drinking water, but whether the other cold taps are supplied by the mains I cannot tell (do your cold taps stop flowing when you turn off your stopcock?). The cold mains supply will also be heading up to the loft, where it supplies the CWS (and possibly a F&E).

I asked whether your boiler has a pressure gauge? If it does, it's 'sealed' (unvented), and you will not have a small F&E tank in the loft alongside the larger CWS. If the boiler does not have a pg, then almost certainly you will have a F&E tank in the loft - this type of CH system is 'vented', and is kept topped up by this small tank.

Both the CWS and the F&E tanks are strong candidates for your water loss, so I'd get up there with a bright torch sooner rather than later - see if either is constantly filling.

I would not bother contacting the WB until then, and you have already determined that the meter moves only when the stopcock is opened? Worth double-checking that's the case if you are not 100% certain.

grumpy_codger

Jumper55 said:

... Someone mentioned an F&E tank - sorry I dont know what that is?

Feed and expansion tank - small one for the CH system.

FreeBear

Get yourself a large screwdriver. Press the pointy end against the cold water pipe, and put your ear on the other (blunt) end. With the stopcock open, you may be able to hear water running if there is indeed a leak.

Any copper or lead pipe running through concrete is a potential spot for a leak to develop (the cement attacks copper & lead over time). Plastic pipe rarely fails unless the water inside has frozen.

Jumper55

Thanks again for all the comments and suggestions.

I got up in the loft and the pipe into the cold water tank was dripping.  I wiggled it about a bit and the dripping stopped.  I then checked the meter readings a hour or so apart and it hadnt moved so it must have been this that caused it.

Its still a mystery where the additional water has gone because there's no evidence of it coming out of the overflow pipe (no dripping, no wet patches where it would have landed.)

Im going to monitor it over the next couple of weeks to make sure that this is what was causing it.

As there are no other signs of water leaks in the house, fingers crossed that this has solved the issue.

Thanks again for your help.

WIAWSNB

Thanks for the update.

Of course, the ballvalve on the CWS will be dripping whenever it shuts off a refill, and that would be normal.

You know where the overflow exits, then? Good - just keep an eye on that. Is there one or two (ie separate for the F&E tank?)