Sewer smell from toilet

17 Feb 2007
Reaction score
United Kingdom
Help please

Recently had new shower suite fitted downstairs as part of extension but having problems with bad smell from toilet. This only seems to occur when the shower is in use. No problem any other time with the toilet or sink and the smell doesn't come from the shower, just the toilet.
There are traps on the shower and sink with the waste from both running into the toilet soil pipe on the external wall.
Not sure if the reason could be that the soil pipe from the new toilet doesn't have a vent at the top, it just runs into the ground and meets with the waste pipe from the tall soil stack which is vented.
The plumbing was all checked and passed by building control so i'm a bit confused to what the cause could be.
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can you determine where exactly the smell is coming from? Is it the toilet bowl? This should be highly unlikely as the water in the toilet as a block to sewer smells.

The only other place it may come from is the waste pipe as it connects onto the soil stack. Can you see any gaps in the rubber seal?
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Are you sure its not coming from the shower trap, when you next smell it check the trap has still got its seal.
:LOL: :LOL: :LOL: :LOL: :LOL: The smell is coming from the overflow, they should have fitted an internal overflow.

Well guessed YNG.

I actually have the same problem at home. Although the bog has an internal overflow.

But as the whole lot is being ripped out soon; I can not be fagged to find out until the work starts.
Thanks for all the responses.
Have checked the waste connection at back of the pan and it seems fine. (secure/no gaps).
The smell is definately coming from the toilet, everything else seems ok.
Will look to confirm the overflow setup. Would expect there to be an internal one as there is no other pipe outlets other than the waste pipe.

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