Drainage from washbasin and bath

[DIYm1]

I have just managed to successfully unblock the drainage pipe of the washbasin in the bathroom - The flow was very sluggish and the sink went half-full / full every time you use it to wash eg your hands...

It took me some strenuous efforts (plunger did not work) - I used a can of gas (the ones that are sold at the local DIY store) and in solving the washbasin problem, in turn, the bath got blocked as I forgot to plug the bath drainage hole, and I guess the muck must have got pushed up the drainage pipe of the bath (The drainage from bath and washbasin must be linked somehow before draining out of the bathroom??) - Steep learning curve re the drainage pipe system of the bathroom.... After much persistent efforts, I managed to shift the muck down the bath drainage pipe into the main drainage pipe using the gas can...

Anyhow, problems solved re washbasin and bath ie flow is fine.
However, I have noticed that there is now a gurgling noise every time the water drains out.
My guess is that this is a good sign that drainage is very good indeed as per my obaservations.

Can you please confirm my suspicion or comment on this gurgling noise. Thanks!

 

[sloss]

It's probably not 'back vented'.

It may not have a pipe that goes outside or connects into the soil stack above any drain connection to allow air in to avoid the traps being pulled to drain.....

 

[Nige F]

Indeed it`s probably not vented ....but a modern solution is to fit a Hep V O waste valve in place of the trap

 

[DIYm1]

Thank you for your thoughts, guys!!
If it is not back-vented, is this a major problem at all That is, do I need to have the system looked and fixed?

FYI:
The drainage pipe from the bathroom connects to the main waste pipe (soil stack?) on the outside wall of the property just below the first floor level.
The top of the stack is normally open to the air at the roof level - It is still open to the atmosphere except that the open pipe is inverted, ie it is now pointing downwards.
(A few years ago, a storm broke the joint, and the previous owner said to us that it has not been a problem to them since - they left it unrepaired...)

How essential is it to fix the inverted soil stack ventilation pipe