Leaking toilet/bathroom waste

15 Jan 2008
Reaction score
United Kingdom
Hi guys,

I've got a leak from the 110mm waste pipe from my toilet. Directly below the toilet is a (inverted) t-joint on the waste pipe so that the longest part runs almost parallel with the floor and the shorter bit points up towards the toilet. The toilet waste goes into the shorter bit from the top. In the end (back) of the longest part of the pipe is a 'bung' (for want of a better word) with a hole in the centre into which runs the 40mm waste pipe which comes from the WHB and the bath. The 110mm t-joint is leaking around the edge of this 'bung'. It doesn't appear to leak when the bath/whb waste is running, but leaks pretty much every time the toilet is flushed - not much, but anything is too much!!

Any ideas how I can stop it? Do these 'bungs' just push in? It looks like it is in as far as it'll go? Do they degrade over time and require replacement? Should it have been sealed with something (sealant??), or they designed to seal themselves when they're pushed in tight? Does this even sound like the correct way for it to have been plumbed? With these all being right below the toilet pan its incredibly difficult to get to now :confused:
Sponsored Links
A picture might help.
If understand correctly you have T junction where one opening deals with evacuation to the stack, one opening is connected to the WC, and the third has a socket inserted with basin waste in to this.

You could always be brave and see if you can reseal it.
Hmmmm, as I say, as its right below the toilet pan, access is not easy so taking a picture didn't really work (I tried to do that when I was locating the leak in the first place, but it didn't help...).

You seem to have understood my description though.... What does re-sealing it mean/involve? How does it 'seal'??

I assume that would involve removing the 'socket' and hence I'd need to be brave to cope with what will come out of the pipe when I do that?
It depends where the leak is from, if it is coming from external of plug then that will need removing and can be sealed with silicone.
Sponsored Links
Hi Guys,

Thanks for the responses. Why would the bung have failed though? Do they fail over time? Or is it likely its been leaking since it was done (its less than three years old and the house was empty for 6months of that time - it only leaks when the toilet is flushed and only a little bit, so it seems feasible to me that the mineral wool insulation and the plasterboard could have been soaking up the leak and drying out for that length of time until the plasterboard has finally lost its strength and given up...??)

If these bung things generally do fail after time, it would seem a better option would be to maybe put the bath/whb waste into the SVP via a boss adaptor on the top/side of the pipe and seal the end of the SVP up altogether? Then the entry for the bath/whb waste into the SVP would be above the line of the water flow in the SVP and therefore the problem would be removed completely....?

But if the bung has probably just been leaking since it was installed then replacing it would be an easier option....

Took it all apart at the weekend - not nice, but not as bad as it could have been! Anyway, the 'socket plug that went into the 110mm t-joint was a plastic plug with rubber fins pushed onto it. What had happened is that the rubber fins had moved slightly off the plastic part of the socket and so it wasn't sealing properly. I can only assume it has either always been like that, or that there must be a tiny bit of movement when the toilet is flushed and over time its slowly moved and the rubber fins have moved off the socket plug.

Replaced this with a solid plastic socket plug and re-routed the 40mm waste into the top of the 110mm pipe with a boss adaptor, which seems to me to be a better solution and up to now, seems to have solved the problem.

Have also learnt that 40mm pipe doesn't always measure 40mm..... :confused:

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local