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Sandra Kenny-Jones

Hello there. I'm hoping somebody can provide me with some guidance on an issue that's been ongoing now for over 2 years! Thames Water moved my home onto a smart meter and ever since then, the daily water usage is showing that water is being used every night between midnight and 7am. On average, it's in the region of 10-15 litres per hour so a considerable amount. They have confirmed that it's definitely not a shared meter issue and are adamant that I must have something on a timer that is using water overnight, but I don't. I have a Worcester Bosch combi boiler. The hourly water readings are normal during daylight hours and there are several hours where no water is being used in the day so it's definitely not a leak. Clearly I want to try and find out the source of the problem but don't have a clue where to start. Any ideas welcomed. Thank you everyone.
 

SandraKJ

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I thought I would share a screenshot of a typical day's usage (based on the daily readings from Thames Water)

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SandraKJ

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I thought I would share a screenshot of a typical day's usage (based on the daily readings from Thames Water)

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On the graph above, I was actually away overnight so there wasn't even anyone at home and yet I was still getting readings showing that I'm using water. I'm really not happy that I'm paying for water that I'm not even aware that I'm using. Anyone else ever come across this before?
 

Undertrained

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First port of call would be to check any toilets with internal overflows. Usual suspect is a close coupled toilet. Had it several times where I work in customers houses.

What I suggest you do is take a meter reading, then again at 7am, see if there’s a difference.
 

SandraKJ

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First port of call would be to check any toilets with internal overflows. Usual suspect is a close coupled toilet. Had it several times where I work in customers houses.

What I suggest you do is take a meter reading, then again at 7am, see if there’s a difference.
Thank you for contributing. I've had a plumber check the toilet and nothing found to be wrong there. It's really weird as there is water usage every single night even on nights when I'm not home (always between midnight and 7am) and then normal usage throughout the day. If it was the toilet, how comes the water usage isn't consistently recorded 24 hours a day?
 

SandraKJ

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Thank you for contributing. I've had a plumber check the toilet and nothing found to be wrong there. It's really weird as there is water usage every single night even on nights when I'm not home (always between midnight and 7am) and then normal usage throughout the day. If it was the toilet, how comes the water usage isn't consistently recorded 24 hours a day?
Sorry - forgot to add, if I do get a plumber out again, what would be the remedial action they would need to take to fix the problem? Is it a simple fix from your experience? Thank you. :)
 

gpbeck

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214
There may be an isolation valve to your cistern ( a kind of tap turned with a screwdriver). If so turn it off before going to bed and check your water usage the next morning.
 

Undertrained

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If it is the toilet, there’s a chance it could be intermittent. One idea, a self remedy, would be to add food colouring to the cistern and see if it runs in the pan (don’t flush initially, obviously).
 

Chuck

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It would help if you could give us some more information about your system. Do you have a hot water cylinder? Combi boiler? Shower? How many storage tanks in the roof?
 

steadyon

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1. Like other above, I would suspect a WC.
2. At night, water pressure tends to rise as no one is using it. If you have a faulty WC inlet valve, the extra pressure may be causing it to let by at night, and the excess water is flowing away down an internal overflow so you never see it.
3. Suggested actions:
3a. First thing in the morning, before any water usage, check each WC cistern to see if water is above the normal fill line and at the level of the overflow. You might want to check the fill line by flushing and allowing to refill until it stops during the day.
3b. Turn off the water at your main incoming stopcock at night and take meter readings, in case there is a leak similar to 2. above between your meter and the main stopcock.
 

Chuck

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OP has stated Worcester Bosch Combi boiler (Post #1).
Thanks, missed that.

The night time behaviour makes me suspect a crack in a metal component. I've got the cartridge from a ceramic kitchen tap in front of me now that behaved almost identically to the above. No, or very slight, dripping during the day, but by midnight it was dibbling up to 10 litre per hour.

If the OP wanders round at 0400hrs and listens carefully they'll probably hear something running/dripping.
 

ShaunCorbs

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Easiest way to tell turn the mains off at night and see if you still have usage if you do it’s something before the main stop tap
 

SandraKJ

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If it is the toilet, there’s a chance it could be intermittent. One idea, a self remedy, would be to add food colouring to the cistern and see if it runs in the pan (don’t flush initially, obviously).
Thanks so much for that suggestion. I will definitely give that a try. I'll let you know how I get on. :)
 

SandraKJ

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14
1. Like other above, I would suspect a WC.
2. At night, water pressure tends to rise as no one is using it. If you have a faulty WC inlet valve, the extra pressure may be causing it to let by at night, and the excess water is flowing away down an internal overflow so you never see it.
3. Suggested actions:
3a. First thing in the morning, before any water usage, check each WC cistern to see if water is above the normal fill line and at the level of the overflow. You might want to check the fill line by flushing and allowing to refill until it stops during the day.
3b. Turn off the water at your main incoming stopcock at night and take meter readings, in case there is a leak similar to 2. above between your meter and the main stopcock.
Hello Steadyon. :) Thanks for your suggestions. I've only got the one toilet so hopefully that simplifies things. I tried a number of things last year. I turned the internal stopcock off for 3 consecutive days and the meter was still recording usage overnight between midnight and 7am. It had no effect at all. I then turned it off at the mains and it recorded no water usage at all between midnight and 7am. I thought it was resolved as many months went by with no (or minimal) water being used overnight but it's gradually creeping up and is now running at circa 10 litres an hour through the night. I don't know if that signifies that there is a leak between the mains and the internal stopcock but I'm hoping the fact that there are hours in the day with a zero reading means that this is unlikely. Really appreciate your guidance as a 3 year war over this with Thames Water has me totally beat. So thank you. :)
 

SandraKJ

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14
Thanks, missed that.

The night time behaviour makes me suspect a crack in a metal component. I've got the cartridge from a ceramic kitchen tap in front of me now that behaved almost identically to the above. No, or very slight, dripping during the day, but by midnight it was dibbling up to 10 litre per hour.

If the OP wanders round at 0400hrs and listens carefully they'll probably hear something running/dripping.
Thanks, Chuck. Really hoping it is the toilet and nothing sinister leaking underground! I shall see if I can force myself out of my slumber to have a listen. I'll let you know if your hunch is pointing me in the right direction to getting it fixed. Really appreciate the support and input. Thank you. :)
 

SandraKJ

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14
Easiest way to tell turn the mains off at night and see if you still have usage if you do it’s something before the main stop tap
Thank you for your guidance. When I've tried this before, I have still had water usage recorded when I've turned off the internal stopcock overnight but if I turn it off at the mains instead, there is zero water usage recorded.
 

Chuck

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Thank you for your guidance. When I've tried this before, I have still had water usage recorded when I've turned off the internal stopcock overnight but if I turn it off at the mains instead, there is zero water usage recorded.
Unless your internal stopcock is 'letting by' at least 10 litre per minute, which should be straightforward to confirm/rule out, your leak is between the meter and the stopcock.
 

ShaunCorbs

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Sounds like you have a leak in your supply pipe
 

Chuck

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Sounds like you have a leak in your supply pipe

Last time I looked into this, the water company would pay for one repair to the supply pipe to a property. This was despite it technically being the home-owner's property. I guess that they have a water-loss via leaks target that such fixes help meet?

Anyway, worth investigating.
 

ShaunCorbs

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Last time I looked into this, the water company would pay for one repair to the supply pipe to a property. This was despite it technically being the home-owner's property. I guess that they have a water-loss via leaks target that such fixes help meet?

Anyway, worth investigating.

Depends on the water board most charge but wave the water used / over used
 

Murdoch

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Is the clock correct? Having periods of no usage during the day does look strange
 

SandraKJ

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Unless your internal stopcock is 'letting by' at least 10 litre per minute, which should be straightforward to confirm/rule out, your leak is between the meter and the stopcock.
It's all a bit weird as if there was a leak between the meter and the stopcock, surely this would show throughout the day. What happens is that when I'm away overnight it records zero usage of water during the day/evening but still shows usage overnight ... see image below. I was away on New Years Day and came home at 3pm. This pattern below is typical of what happens and Thames Water keep saying something must be on a timer and using water but I don't have anything that would do this. Don't really know who to get to look at it ... does it need to be a specialist do you think?

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SandraKJ

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Is the meter on the property boundary.
Hi there ... the meter is outside on the pavement and Thames Water have installed a new meter but still the same issue. Below is an image of the type of usage overnight - I was actually away from home - water usage overnight - nothing all day and then starts again at 11pm. I'm at a loss as to work out why ...

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SandraKJ

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Depends on the water board most charge but wave the water used / over used
Any idea of who is best placed to investigate? Do I need a specialist of some sort? Thames Water aren't interested as they say their obligation ends at the mains supply on the pavement. :-(
 

ShaunCorbs

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Any idea of who is best placed to investigate? Do I need a specialist of some sort? Thames Water aren't interested as they say their obligation ends at the mains supply on the pavement. :-(

Yes they should have a list to approved contractors but you want the water meter checking first as it might be faulty etc might save you a call out from a pro
 

SandraKJ

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Yes they should have a list to approved contractors but you want the water meter checking first as it might be faulty etc might save you a call out from a pro
Thanks so much. They've already changed the meter over so it looks like we can rule out a faulty meter.
 

Murdoch

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Hi there ... the meter is outside on the pavement and Thames Water have installed a new meter but still the same issue. Below is an image of the type of usage overnight - I was actually away from home - water usage overnight - nothing all day and then starts again at 11pm. I'm at a loss as to work out why ...

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Thats really weird.

How do you heat your house and water?

Garden irrigation system?
 

Undertrained

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I’m not sure if this has been asked, and I can’t check as the site is advert crazy today. Have you checked the meter serial number with your bill is the same? I think someone could be tee’d off your main?
 

SandraKJ

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Thats really weird.

How do you heat your house and water?

Garden irrigation system?
I wasn't home - I was away. The image shows that even though I wasn't there, I was still "using water" in the early hours of the morning. I have sometimes been away for 3-4 nights and there is NO water used between 8am and 11pm but from midnight through to 8am there is anything between 1 - 15 litres an hour. I'm baffled.
 

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