Smelly sink drain - Lack of space (advice please)

1 Oct 2008
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United Kingdom
Our sink drain is constantly smelly.

We are pouring bleach down here frequently and I have removed the pipes to clean etc but the smell always comes back withing 24hrs.

Its a triple sink connection with a dishwasher also.
I think the main issue is that there is no fall on the waste after the U bend.

Can I move the dishwasher waste connection so that it is horizontal rather than vertical (as is currently) so I can win a little more fall on the exit connection

Any advice appreciated.

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If no water from the dishwasher comes up the sink waste, there is little to gain from moving it's connection.

The usual suspect is the sink overflow. They often get a bit damp at the bottom when the sink drains, but there usually isn't any flow through them to keep them clean. Have you tried dosing the overflow with bleach?
Try temporarily plugging the overflow with something like a dishcloth to see if it is the culprit.

A different waste arrangement, with seperate traps directly under each sink bowl would leave the minimum of potentially smelly pipework above the trap seals, but would cost some cupboard space.

A long run of pipework after the trap can draw the water seal from the trap as it drains, allowing sewer gases back up the waste. If thats, the problem, adding an air admittance valve or changing to an anti-syphon trap may be the answer.
Just take the whole section out white waste pipes out and clean them. Grease dirt etc etc build up on the sides of the pipes and its that that stinks !!! do this and itll be fixed.
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Do a service wash.
(this should be done once a month to keep all pipes running clear)

Turn on washing machine, on its hottest wash (90 degrees) and let it run full cycle. Make sure you don't put anything in it.

This is not only good for your pipework but also your washing machine.


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