bad egg smell from basin

20 Jul 2006
Reaction score
United Kingdom
We have been getting a terrible smell in the kitchen when using the upstairs bathroom washbasin. The drain is clear and running freely and there is no smell in the bathroom or outside from the drain which isn't blocked as it's just been checked. Help please!
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from the sound of it, the flow from the upstairs sink is siphoning the water out of the trap in the kitchen sink. Once the water in the kitchen sink trap is gone, there is nothing to prevent drain smell from coming out of it.

I think you can buy an anti siphon kit to cure this problem.
Thank you for your replies.We haven't got a cess pool and it can't be affected by the kitchen sink because it's a separate drain system,the basin drainpipe is at the side of the house and the kitchen one at the back and they go into separate drains.
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Bad egg smell is from Hydrogen Sulphide...drain smell is different (In my opinion )try some Jeyes Fluid down various drains a 5 litr because the small tins are ££££££
Is the bathroom above the kitchen? Or where?
Yes the bathroom is above the kitchen and it's a combined bathroom and toilet with the toilet on the outside wall and the basin on the inside wall.The kitchen sink is at the back of the house.
susiep53 said:
We have been getting a terrible smell in the kitchen when using the upstairs bathroom washbasin.

And the bathroom is above the kitchen.

What would happen if there was a plumbing leak in the bathroom waste pipe, that dripped onto the kitchen ceiling or down any ducts or plasterboard kitchen walls?
Check the overflow on the kitchen sink. It could be full of festering gunge, especially if it dips below its connection to the waste. Also suspect that trap water seals might be lost due to syphonage or evaporation. Are there other waste connections in the kitchen (washing machine, dish washer) which could have lost their seals?
Good one Chris ...............Hydrogen Sulphide can come from bacterial action on crud (or a Kipp`s apparatus)
If you have a dishwasher that runs into your trap this can all so cause smells take your u bend off and check to make sure it is clear, also clean your dishwasher waste pipe that go into the trap
Thank you for your replies,some being more helpful than others!
We don't have a dishwasher but the smell seems to have gone because I squirted bleach down the bathroom basin overflow slit. So a special thank you to the person who mentioned the sink overflow. Fingers crossed that might have done the trick!
Sue xx

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