Very high water bill mystery!

[crowman]

Hi, hoping someone can help.

Recently received a water bill that was more than double the expected amount with no obvious explanation for the extra usage. Done some checks for leaks inside and out as per the water company advice but found nothing. Water company came out and did their own checks and said there was no leak and the meter was behaving as expected. However they decided to change the meter anyway as it was old. The new meter was installed yesterday at 2pm and by 8pm the reading was already 290 litres used despite no-one in the house using water and no appliances that would use any. Today at 6pm the reading has leapt to 810 litres used despite very minimal use last night and this morning only. With a volume use that high if there was an internal leak it should be obvious. The meter is specific for my house and unless someone has tapped into my supply I am puzzled how this could be happening.

Any thoughts would be appreciated.

 

[ShaunCorbs]

With no water running eg taps off showers off don't flush a toilet is the meter turning ?

 

[crowman]

No, when I tested it it wasn't and when the water company guy tested it it wasn't yet at some point in the day the reading has dramatically increased which would seem like a sporadic problem or someone drawing water (but not me as the house is empty all day). I have turned my outside tap off so no-one can be using my supply that way.

 

[ShaunCorbs]

Anything new in your house / any work gone on ?

 

[crowman]

Not since early 2016 when a new kitchen was fitted but there was very minimal plumbing andall pipes are in places where any leak would be obvious by now. The water company have confirmed I was using approximately 109 litres a day for years but in the last year the consumption has gone up to 300 litres a day and now over 500 litres a day despite my circumstances changing where I know I am using even less than ever.

 

[ShaunCorbs]

Any toilets overflowing or tanks in the loft ?

 

[crowman]

No both the toilet and the cold water tank in the loft were checked and no leaks and are filling up to a level lower than the overflow‎.
There was one strange thing that occurred whilst the stopcock was turned off for testing. It was off for about 3 hours and during that time no water was used in the house. However when the stopcock was turned back on the cold tank proceeded to fill up loudly and at speed implying that it had somehow part emptied during that time. The water is not coming out of the overflow and there is no leak in the loft‎. The only other pipe that leads from the cold tank goes into the hot tank in the airing cupboard. I can't see any way the hot tank could be emptying thus requiring a refill from the cold tank. The hot tank only heats at night on economy 7 and the hot pipes leading from it run under the floorboards upstairs and then through the bathroom and down the wall into the kitchen. If any of these pipes were leaking that volume I think I would have a collapsed ceiling or flooded floor by now! I have no central heating so no pipes run under my downstairs floors.

 

[sammathias]

Are you sure you dont have any hot water pipes feeding your downstairs kitchen under a screed floor?

 

[crowman]

My hot water pipes for the kitchen run down the corner of the wall from upstairs. Have attached a picture to show what I mean.

 

[sammathias]

I see. Is that your main stoptap coming out of the floor, pictures slightly blurry. And your hot water cylinder is upstairs?

 

[crowman]

Yes that is the main stoptap and the hot cylinder is upstairs in the airing cupboard. I have a small house with no central heating so the plumbing is limited to the back of the house only in the kitchen and bathroom and cold water tank and hot water tank are also in the back area of the house.

 

[Sharp Point]

Where is your meter actually located and sorry for sounding condescending, but how did you actually check for leaks?

 

[crowman]

The meter is located in the ground across the drive about 25 ft from the house. I followed instructions from water company by checking the meter for any movement while stoptap was on and off. The water company guy also did this and claimed there were no leaks. I then looked in water tank in loft and toilet tank for leaks. I can't see all of my internal pipes but they are all either under upstairs floorboards or running down a wall where a leak of this much would have been visible by now.

 

[Sharp Point]

The meter is located in the ground across the drive about 25 ft from the house. I followed instructions from water company by checking the meter for any movement while stoptap was on and off. The water company guy also did this and claimed there were no leaks. I then looked in water tank in loft and toilet tank for leaks. I can't see all of my internal pipes but they are all either under upstairs floorboards or running down a wall where a leak of this much would have been visible by now.

Again sorry for sounding condescending,but when you tested did you shut off internal stop tap and leave the outside stop tap/ meter open and leave for a few hours, to see if the meter moved?

 

[crowman]

That's fine I welcome your questions to hopefully get to the bottom of this. I had the stoptap off for about 3 hours and there was no movement. When the water company guy came he said if there was a leak he could have seen even the tiniest drip showing on the meter.

 

[sammathias]

You had your internal stoptap off for 3 hours with your external tap on and no water passed the meter?

 

[crowman]

The reading stayed the same so I assumed not.

 

[sammathias]

Sorry what bogrodder is trying to say i believe is...leave outside tap on and turn internal stoptap off. If meter passes water your leak is on the main inbetween the 2 stoptaps. If that passes then try it with both taps on and dont run any water. If the meter passes water your leak is after your internal stoptap.

 

[crowman]

The meter did not appear to change reading on either of those tests when I did them or when water company guy did them. He reported back no leaks to his office so they are claiming I must have used that volume of water which is impossible in the circumstances I have.

 

[sammathias]

I see. What i find puzzling tho is that you said your cold water storage tank partially drained during the time your water was off.

 

[crowman]

Yes me too and no-one I have discussed it with prior to now can offer an explanation which is why I have come here. I desperately want to get it sorted if only I knew what was wrong as my bill is over £600 and rising every day.

 

[Chuck]

Yes me too and no-one I have discussed it with prior to now can offer an explanation which is why I have come here. I desperately want to get it sorted if only I knew what was wrong as my bill is over £600 and rising every day.

Check the operation of the float valve in the tank that mysteriously drained while the stop-cock was off. Then tie it up in the 'closed' position. Use a piece of wood placed across the top of the tank to tie the the string to if necessary . See if (a) the leak stops and (b) the tank level drops. Measure the rate of fall in the tank in cm per hour and estimate how many litres per hour it corresponds to.

 

[crowman]

Thanks I will give that a go in the morning.

 

[neilrj]

Some meters have a little turbine wheel spinning that shows miniscule water use (that is still significant over time) and easily indicates flow long before a digit will move.

 

[Chuck]

Thanks I will give that a go in the morning.

Another thought is that 800 litres over 28 hours is about 0.5 litres / minute. If your toilet(s) have an evil American mechanism known as a 'flap valve' rather than an honest-to-goodness traditional British siphon, it's quite possible for them to quietly leak this amount into to bowl and you will only notice it if you look really carefully.