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Help my plumber doesn’t know

  • 01-04-2024 10:59pm
    Registered Users Posts: 8


    We live in a new build that we engaged a contractor for.
    The plumbers he uses are not very good and seem clueless with an ongoing problem.
    Sewer gases coming from one of our upstairs bathrooms. The shower and the bathtub.
    And also out of the toilet in a powder bathroom downstairs that is on the same line.
    It seems the flushing of the toilet (wall hung crosswater cistern and toilet) is emptying the p trap in the shower and bathtub… we use the shower daily but if the toilet is used regularly the smell comes back quickly too. It have to run the shower a couple of times a day to get rid off the smell. I can’t seem to get rid off the smell in the powder bathroom though.. there is only a toilet in there and nothing else..

    I believe it’s a venting issue but the plumber doesn’t know what to do.. hes been here a few times about this issue but it’s still not resolved.

    There’s also the issue that one of our toilets in particular splashes water when flushed.
    I got the plumber to change the amount of water that the cistern holds to eliminate the problem but it has only worked temporarily. This wc is also upstairs but on a different line but has the same toilet / cistern as the smelly bathroom… but never any sewer smells there.

    Any suggestions what to do?

    I’m thinking I’ll have to find a new plumber and pay out of pocket to get this resolved..
    but I would like to know what can be done to solve this
    We have a septic tank.
    The plumber has checked the line and it was clear, no blockages.



  • Moderators, Home & Garden Moderators Posts: 6,233 Mod ✭✭✭✭Wearb

    Your builder has to stand over this (unless it was self build). If his plumber can't solve it, then he's got to get someone else.

    If you get in someone it's likely to muddy the waters and weaken your hand.

    Please follow site and charter rules. "Resistance is futile"

  • Registered Users Posts: 7,507 ✭✭✭the_pen_turner

    if the toilet is pulling the water from the traps it must be a venting issue . surely a air admitance valve would solve it.

    how those traps attached to the sewer pipe. is it internal , external, is there a vent stack , is there enough ventilation at the tank and percolation.

    are you sure the smell is coming up the pipe and not through a hole from outside or through a vent in the wall or window.

  • Registered Users Posts: 8 tenya

    the smell is coming out from the shower drain especially and also the bath tub drain not from outside and not from the toilet or sinks.

    The waste pipe is going from the toilet down into the suspended ceiling through the kitchen and then out the wall.

    Im not sure what venting there is.. we have slate vents on the roof.

    I believe the septic tank and percolation are properly vented and not the issues as we don’t have any smells coming in in the other upstairs bathroom.

    On reddit someone said probably a major fixture fitted over a minor..

  • Registered Users Posts: 7,507 ✭✭✭the_pen_turner

    is there a 100mm pipe going up the side of the house somewhere . there should be to allow air into the system to stop the suction from flushing the toilet. it allows smells to escape up high and away from windows where you wont notice.

    am i right in thinking you have a boxed in cistern with the toilet bowl mounted on to the boxing . is that tiled. the toilet waste pipe then goes down into the ceiling and outside before going down to the ground. or does it go down to ground level inside the house and then out. if inside can you get access to it .

    sounds like the bath and shower are bossed into the toilet waste. thats ok but there needs to be a way to let air into the pipes so that when you flush the toilet a vacuum isnt created behind the flush water. this vacuum is whats pulling the water from the traps.

    putting in an air admitance valve now depends on how much demo is needed to get to the pipes to fit it.

    either way thats not your problem . get the plumber or builder to fix it and make good the damge getting there

  • Registered Users Posts: 8 tenya

    yes there’s a pipe on the back of house. It comes out and then goes to ground. So it is accessible. It goes up to eaves levels for letting out the smell.

    Exactly the cistern is in behind a stud wall. It is actually not tiled. So would only have to open the dry wall and fit the vent on the waste pipe of the toilet in the stud. And then close again.. plaster and paint.

    I rang the builder today and he said the plumber will fit the AAV under the wash basins , that that should help with it 🤷🏼‍♀️

    appreciate your input, thank you!

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  • Registered Users Posts: 8 tenya

    the AAV under the wash basin helped.

    Can’t believe I had to wait 4 months for this 😫