Why do my sinks & baths gurgle?

BatOutOfhell

Our house is about 6 years old and this has only started in the last few months but is beginning to drive me mad!
Every time we use a tap upstairs the waste pipe gurgles once the water has gone down the pipe. I though it was the u-bend on the sink at first but that is clear. Then I noticed that ALL the upstairs sinks are doing it and the bath and they also do it after a toilet has flushed!
So basically any water going down the waste/soil pipe (are these the same pipe?) will make the whole system gurgle.
We don't appear to have a blockage as all the sinks and the bath drain freely and nothing ever gets "backed up" IYSWIM.
Anyone with any plumbing/drains experience can help me out here please?

muckybutt

Sounds like the sink and bath waste are connected as one into the stack, ideally sink and bath waste should be seperate pipes then you shouldnt get the gurgle !
Ours is exactly the same until the summer comes, then im going to re pipe it.

BatOutOfhell

muckybutt wrote: »

Sounds like the sink and bath waste are connected as one into the stack, ideally sink and bath waste should be seperate pipes then you shouldnt get the gurgle !
Ours is exactly the same until the summer comes, then im going to re pipe it.

Well that sounds possible as there is only one soil stack coming out of each bathroom and going down to the main drain outside. But I can't possibly re-pipe 3 bathrooms! Isn't there another way?

Why has it only just started doing it?

anotherbaldrick

Does the main soil stack terminate either through the roof or at roof level with a vent terminal ??
ie. can you see the outlet point of the pipe at roof level ??

If no pipe is visible your system might be fitted with an Air Admittance Valve which is sticking and air is being pulled in through the traps.
Have you done anything up in the loft over winter ??

BatOutOfhell

We don't have a loft - the bedrooms are all in the eaves. Soil stacks don't protrude through the roof at all so maybe you are right.
How do I work out which one of the Air Admittance Valves is sticking? and how to I get to it?
there are 2 soil stacks, one of them is shared between 2 bathrooms)
Can't extend the soil pipes through the roofline due to planning issues so am stuck with the arrangement.

anotherbaldrick

I assume you have sloping mansard roofs to the upper storey. At low level in the bathroom or bedroom areas is their any removable panel which gives access to the void behind . This would be a likely place for the valves to be fitted. Alternatively their could be a panel behind the WC cistern. Are your builders still around to ask ?

BatOutOfhell

They are both boxed in behind tiles!! I know where they are and I wouldn't really want the original plumber back - he piped up my hot and and cold bath taps the wrong way round and didn't notice! Kept wondering why hot water came out of the cold tap and the hot tap never got hot.....
Will live with it a bit longer - there are no nasty smells - until we can afford a tiler aswell as a plumber!
Thanks for the advice though - it's really helped.

anotherbaldrick

That's OK . When you do eventually get around to fixing them I would suggest relocating them or at least fitting a removable panel because they do malfunction occasionally.