Basin/Bath Blockage Conundrum

[redlos]

Hi All.
Sorry this is long.
Just wanted some suggestions/ideas about a problem we have.
So from time to time I have had problems with either, a slow draining bath after pulling the plug out (and sometimes when the plug is pulled out water is drawn up into the basin sink, before then flowing on or more often, when using the sink, when the plug is pulled out or water is simply running straight down the plug hole, water backing up into the bath.

So this week the bath water was draining even more slowly and making lots of gurgling noises, and for a few minutes after the water had gone down, a sort of gulping sound was coming from the plug hole. And even when that stopped, I’m pretty convinced I could hear that gulping sound as though further away somewhere.

I tried some drain unblocker, but that’s actually made the problem worse! Anyway today I lifted the manhole cover in the garden, in case there was a blockage there. Whilst I was in the garden, I got my friend to run the basin tap and initially the water flowed fully into the pipe I was looking at (don’t know the term) but then it stopped and I presumed they had turned the water off but they called down to say the water was now backing up into the bath. There was no visible blockage on my end I got them to flush the toilet and that flowed through fine too.

So I can’t understand how water can flow down perfectly well but then stop and basically get pulled backwards up into the bath rather than continuing its journey downward.

Hope this enough info. Thanks in advance.

 

[blup]

Ideally bath and basin should be in separate wastes, draining into a single pipe can cause a vacuum that creates the gurgling (basically the trap is emptying due to atmospheric pressure). That flow in turn causes the bath to back up. Try an anti siphon trap on the basin first.

Blup

 

[redlos]

Thanks. Could that cause poor draining or do you think that’s a separate issue?
Have had a quick check of the trap under the basin and it’s very short. It is short because it’s within a unit so avoids a drawer.
At present I’m finding it difficult to find an anti siphon trap the same height ie.13.5cm.

 

[dilalio]

What is the soil setup?
Is bathroom ground floor or above?
Flat or house?
Does soil stack go internally or externally and does it have an open vent (SVP) or AAV?
Can you see waste runs?

A sketch and/or photos of waste runs would help us help you.

 

[redlos]

Not sure I can answer all that but

Bathroom on second floor of house. Going from left to right Bath Basin Toilet. There’s a soil stack running internally to the right of the toilet and I believe this vents out through the roof.

Not sure what you mean by water runs but presuming you mean can I see the pipes plumbing water away, not really, other than the traps under both basin and bath are visible.

 

[Madrab]

Are any other sinks, basins etc showing the same symptoms any issue with the toilet? If it's just the sink/bath and they back up and/or slowly drain then chances are the waste run is restricted somewhere along it's length to the stack. Power plunger or wet vac will probably be needed to clear the run out.

 

[redlos]

No,no other sinks and toilet’s ok.

If there’s a restriction (I presume you mean blockage), do you have any thoughts on why the initial water from the basin was able to run freely for 20 seconds or so, before it started backing up in the bath?

 

[dilalio]

If its an internal stack then there is likely no rodding eyes that can be utilised.

Then it's trying to shift whatever it is, using plunger (with overflows blocked off) or wet vac.

As per @Madrab

Try some near boiling water.

 

[redlos]

So thought I’d update so thought I might as well try some more drain unblocker (One Shot again) I put some of that down the basin, not the bath this time. After thoroughly flushing the sink, the bath backed up as before, then I remembered reading somewhere about plunge down softly, then draw back violently, did that about five times. I guess basically causing a vacuum and I had the very satisfying sight of the whirlpool.

The plugs still made a lot of gulping noises once the water had completely drained, so I’ll probably try and change to the anti syphon trap to see if that helps.

Thanks for the advice as always.

 

[dilalio]

So thought I’d update so thought I might as well try some more drain unblocker (One Shot again) I put some of that down the basin, not the bath this time. After thoroughly flushing the sink, the bath backed up as before, then I remembered reading somewhere about plunge down softly, then draw back violently, did that about five times. I guess basically causing a vacuum and I had the very satisfying sight of the whirlpool.

The plugs still made a lot of gulping noises once the water had completely drained, so I’ll probably try and change to the anti syphon trap to see if that helps.

Thanks for the advice as always.

Who sold you the one shot?

 

[blup]

Thanks. Could that cause poor draining or do you think that’s a separate issue?
Have had a quick check of the trap under the basin and it’s very short. It is short because it’s within a unit so avoids a drawer.
At present I’m finding it difficult to find an anti siphon trap the same height ie.13.5cm.

Yes, but need to try different things by elimination IME. Take the drawer out and risk £10.

 

[redlos]

Thanks. Yes I can probably change the drawer shape to fit in the anti-syphon.

 

[redlos]

Honestly don’t remember how I got hold of the One shot Dilalio ?

 

[redlos]

Who sold you the one shot?

I’m presuming you’re wondering because of the restrictions? I got this at least a year ago if not more hence why I can’t remember where.

 

[dilalio]

I’m presuming you’re wondering because of the restrictions? I got this at least a year ago if not more hence why I can’t remember where.

It's really fućkin dangerous stuff!
Believe me, I know!