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Water level in toilet bowl higher than usual, then lower than usual

Discussion in 'Plumbing and Central Heating' started by AVR2, 14 Mar 2021.

  1. AVR2

    AVR2

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    So about a week ago, I noticed that the water level in our downstairs toilet was higher than usual. Coincidentally, this was the same day that the flush in one of our upstairs toilets stopped working due to a disintegrated washer.

    I figured that it was probably due to the kids being overenthusiastic in their use of paper, so I ran a 1.32m pipe/drain cleaner coil down it. I didn't feel any obvious obstructions, and by the next morning the level had fallen to about an inch *below* where it normally sits.

    It stayed like that for a few days, and then suddenly the water level was much higher than it should be after a flush, slowly draining back to the lower-than-usual level after every flush.

    I'm assuming that sorting this needs a proper plumber, but what might the cause be? Higher-than-usual level that drains slowly obviously points to some kind of obstruction further into the drain than I can reach, but why the lower-than-usual level?
     
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  3. CBW

    CBW

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    Sounds like a blockage, and one that’s siphoning some of the water out of the trap.
     
  4. terryplumb

    terryplumb

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    Partial blockage . Do you have a manhole on your property ?
     
  5. AVR2

    AVR2

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    I'm not actually sure if we have a manhole.
     
  6. dilalio

    dilalio

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    Here's one I did earlier...
    IMG_20210314_135404.jpg IMG_20210314_141634.jpg
     
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  7. Hugh Jaleak

    Hugh Jaleak

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    Good grief, I take it the BCO has been nowhere near that! :eek:
     
  8. AVR2

    AVR2

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    OK, the toilet is now flushing completely normally - no hint of backing up - and at the end of the flush the water level is where it normally sits, but over the next few minutes it sinks to below the visible "tidemark" established over years.
     
  9. HERTS P&D

    HERTS P&D

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    You have a blockage.

    Andy
     
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  11. AVR2

    AVR2

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    From my POV as a plumbing layperson, that seems counter-intuitive. What's the mechanism by which a blockage allows an apparently completely normal flush that doesn't back up in the bowl, but actually leads to a *lower* water level?
     
  12. Harry Bloomfield

    Harry Bloomfield

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    Vent or air admittance valve?
     
  13. M1957

    M1957

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    If the system isn't venting properly, which often happens when there is a blockage and the inspection chamber is full of water, then the toilet trap can siphon.

    Vents are there to break the siphon and stop the trap water being sucked out.
     
  14. AVR2

    AVR2

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    OK, I understand... I think :)

    The only manhole cover I can find is in the shared driveway between us and our neighbours (it says "Osmadrain Inspection Chamber"), and it's secured with large screws in each corner, so I'm not going to mess with that, I'll get an expert in.
     
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  15. HERTS P&D

    HERTS P&D

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    Yes, get an expert in who has a screwdriver.

    :ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO: :ROFLMAO::ROFLMAO::ROFLMAO::ROFLMAO:

    Andy
     
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  16. Hugh Jaleak

    Hugh Jaleak

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    Screws simply secure the lid, if they'll undo, then pull the lid up and see. If your neighbour is blocked too, then ring the Water Company, it's their problem.
     
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  17. dilalio

    dilalio

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    Nah... Probably too busy sending an email to someone! :LOL:
     
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  18. DIYnot Local

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