Sink in bathroom is draining up into the bath tub

[doggyvonne]

Newish bathroom in 70s house ..trying hard to avoid a another bill )o: I have tried liquid drain cleaner,plunger and a snake into both plug holes but there really is no crud down there which is obvious.. a little whitish sludge from the bath overflow grill when I plunge. The bath drains beautifully and no noises or problems but if I run taps in sink and drain it it pushes water up the bath tub plughole with some force..a little detritus but not much and a good bit of glug glug bubble.. The toilet flushes very well but there is a curious tap tap noise in the 8" wide pipe which goes from toilet into outside wall and down to the sewer..always done that.
This might seem harmless except for a slightly mucky bath but it is getting worse and I am concerned there is a blockage somewhere which might fracture the pipes or loosen the trap. All does drain away after the bubbling and glugging so water does find its way out but why the forceful noise and the backflow?I really want to manage this myself if I can as we cant afford any more bills before Christmas. Can anyone give some guidance as to what to do? My husband works very late and he is always tired..it's up to me.

 

[Galoka]

does it seem to be water from the handbasin actually going up into the bath, or is it just a glug of water being pushed up?

Can you see how the waste pipes are run/connected together. Maybe a diagram for us?

 

[doggyvonne]

does it seem to be water from the handbasin actually going up into the bath, or is it just a glug of water being pushed up?

Can you see how the waste pipes are run/connected together. Maybe a diagram for us?

all pipes are tiled in so I cant see them but I saw the bathroom installed and the pipes from bath taps run under bath at a slight slope into a tiled step at floor level at the no taps end of bath where the sink is against the wall..there is a 'trap' directly below the bath tub plug hole which can be accessed from the kitchen below via small trap door.
The sink drains normally it's just this spurting up the bath plughole when I let water drain from sink. I think it might be water which went down the bath plughole and sitting there coming up but cant be sure..it isnt nasty and after the explosion it all goes away cleanly.

 

[Hugh Jaleak]

Sounds like a badly plumbed waste, the water from the basin is taking path of least resistance, which is initially, into the bath, before gravity takes over and it finds it's way out. Really need to see how the wastes run before being able to advise further. (The water supplies to the taps will have no bearing on this.)

If the waste has been fitted together properly then it is unlikely to leak or break anything. Seems more likely to be a poorly designed layout on the pipework. Bath may drain ok, but it is already at a low level, water cannot find its own level anywhere else other than in the stack. Unfortunately I doubt much can be done without accessing the waste pipework.

 

[GavThePlumber]

Fit anti vacuum traps on basin and bath.

 

[doggyvonne]

Sounds like a badly plumbed waste, the water from the basin is taking path of least resistance, which is initially, into the bath, before gravity takes over and it finds it's way out. Really need to see how the wastes run before being able to advise further. (The water supplies to the taps will have no bearing on this.)

If the waste has been fitted together properly then it is unlikely to leak or break anything. Seems more likely to be a poorly designed layout on the pipework. Bath may drain ok, but it is already at a low level, water cannot find its own level anywhere else other than in the stack. Unfortunately I doubt much can be done without accessing the waste pipework.

I am puzzled why it has developed and got worse since the bathroom was fitted..it was not doing it at first..where is the waste piework likely to be..is it connected to the toilet as I described i.e the thickest pipe going down the outside wall?

 

[Hugh Jaleak]

If no apparent other arrangement then usual practice would be to connect to the stack. If the waste was altered when new bathroom was fitted then this could easily be the cause of the problem, may be something as simple as a swept tee connecting basin into bath waste is fitted the wrong way round. Schoolboy error but not unknown.......

 

[Galoka]

Fit anti vacuum traps on basin and bath.

Well I did think that, but i'm not sure that it would help here. Seems to me we have the opposite situation from a vacuum, the water going own the basin waste seems to be causing pressure in the pipe pushing water back up out of the bath trap.

 

[longdogs]

Is there enough room to fit a non return valve on the bath waste?

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