bath plughole gurgling and bubbling when toilet flushes

[taza98]

Hi

Sometimes when I flush my toilet in the bathroom, the plug hole in the bath starts gurgling and some splashes off water come up.

Any idea why? Is the waste pipe from them becoming blocked?

Thanks

Taz

 

[mcniven]

Blocked stack maybe..

Castlebrae

 

[Mushybees]

How do the WC and bath wastes enter the soil stack?
How high is your WC branch from the invert of the drain?

 

[LUNAT]

HI

if this started recently then pipes blocked or started to block.
if this happened since pipes/bathroom installation then incorrect piping.
w.c water is coming out from bath which need curing immediately.

 

[AMEdinburgh]

From a DIYer not a plumber. Might it also be the flushing WC creating a negative pressure in the pipes upstream of it, causing air to be taken in through the bath plug hole and the air bubbling through the trap causing the splash back. If you put the plug in and flush the WC is the plug popped out which means it isn't a suction issue or do you then get a gurgling from the sink if it's on the same main drain before going into the stack. If that happens you might need to add an air admittance valve. I put in an ensuite bathroom a decade or so ago with a long 4" branch across a bedroom to the stack at the side of my house and my plumber friend having looked at the plans predicted what you describe, unless one was fitted. Also with the bath trap paritally "sucked out" there was the risk of smell coming back up the plug hole. I followed his advice and put one in with the rest of the waste pipes and have had no problem