Posting a message to the forum will remove the above advertisement
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Checkout our Plumbers Insurance area - heavily discounted Public Liability Insurance and Van Insurance specifically designed for plumbers.

Discuss Strange problem - mains water running for 10 secs every few mins in the Plumbing Forum area at

  1. Adam Jenkins

    Adam Jenkins New Member


    Got a strange issue and hoping someone has some ideas please.

    The other day I needed to switch off the stopcock to work on my toilet. Water was off for an hour or so and since then there is a strange noise every few minutes. It sounds like water running in a pipe and is coming from the same area under the sink as the stopcock. Also in the upstairs airing cupboard I can feel the water pumping through one of the pipes (think it's a cold water mains pipe but not sure).

    I have a combi boiler so nothing going on with a loft tank. Tried turing the boiler off just in case it was related (it's not) and have also bled radiators (there was a fair bit of air in the system).

    The only thing that stops this intermittent issue is turning the stopcock off again.

    Any ideas? thanks in advance!
  2. scott_d

    scott_d Plumber GSR

    Toilet filling
    It may be overflowing internally
    • Agree Agree x 2
  3. Adam Jenkins

    Adam Jenkins New Member

    Hi - thanks but it's not any of the toilets, I checked them. As I say the sound is coming from near the stopcock - the toilets are silent and are not running (well one of them does run a bit sometimes but that's just the inner plug not always sealing properly after a flush - just flushing again solves it) and they are not overfilling...
    • Dislike Dislike x 1
  4. Jim Goodenough

    Jim Goodenough Plumber

    Are you sure you have a sealed system, very rare but it could be the ball-valve opening on F&E tank if it's an open vented system?
  5. jtsplumbing

    jtsplumbing Plumber GSR

    Pin hole in plate heat exchanger.
  6. Adam Jenkins

    Adam Jenkins New Member

    Found the problem and it WAS one of the toilets running that was to blame (sorry Scott_d)!!

    The plug is leaking just a little bit and the water level is only dropping a tiny amount which is why I didn't notice it.

    Thanks a lot for the advice!
    • Like Like x 1
Similar Threads - Strange problem mains Forum Date
Strange question re : using unpressurised boiler for hot water only... Plumbing Forum Jan 9, 2019
Strange smell suddenly coming from boiler Central Heating Forum Dec 16, 2018