Drain smell when toilet is flushed - but no blockage!

[barkerwoof]

Hi,

Everytime we flush the toilet in our house a horrible eggy smells is emitted from the drain outside. This smell only ever appears when the toilet is flushed. It never happens with the shower, sink, kitchen etc.

There is no obiviously blockage, the water goes down the toilet as it should and it fills back up normally afterwards. Furthermore, no smell actually comes up from the toilet itself, just the drain. The drain outside shows no sign of blocking or bringing water back up either.

I am completely confused! I just wanted to check if anyone else had had a similar experience and knew of possible causes before I go through the expense of hiring a professional to come round and take a look.

Your help would be most appreciated!

Thanks,

Matt

[stoneyboy]

barkerwoof,
Depends what you mean by drain, if its a gulley then there is a basic fault with the system, if its a drain cover then you amy have a blockage or the cover is not sealing properly.
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[barkerwoof]

Thanks for your response.

The smell comes up from the drain in which the water from kitchen sink goes into. The one right next to the house - that would then run away to the public sewer. With one of those black plastic drain cover. (Sorry I am complete dunce when it comes to this!)

Ive had the water company come out to check for blockages in the drain, both on mine and the public sewer, but there is nothing. Its all working as it should.

[stoneyboy]

barkerwoof,
If you have a solid black plastic drain cover on the drain next to the house this should seal and not let smells escape. It needs resealing.
If the cover has a grille in it you could have a gulley with integral trap which may be partly blocked. It needs cleaning.
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[barkerwoof]

The cover has a grille. Have you any advice about how I can about cleaning it?

I have poured drain unblocker/cleaner down and although it worked for a bit (maybe a day or so) the problem soon came back!

[stoneyboy]

barkerwoof,
If it is a gulley with an integral trap then you should find fixing screws holding the top bit in place and once this is removed there should be 1 or 2 further fixing screws holding the trap in the gulley. Once you have removed these screws the trap should lift out for cleaning.
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