Smelly kitchen sink drain

[pappyon]

Can anybody advise how to eliminate a bad smell coming up the kitchen sink, which is made of UPVC, the pipes are made of plastic.
Removing and cleaning the trap has achieved very little.[/code]

 

[simon]

Try cleaning yor overflow out aswell.If you've got your waste pipe running downhill all the way bad smells can't get back up as the trap holds an amount of clean water effectively blocking the waste for any smell to come up.If the waste pipe runs upwards at all the trap could just as easily hold dirty water giving you a permanent smelly sink!

 

[breezer]

smells are caused by gas given off from bacteria "having a meal" you would need to kill the bacteria. Have you tried flushing with concentrated bleach

 

[pappyon]

Thanks for the replies to my post.
The waste pipe could certainly have more of a gradient. Whilst it may not run uphill, it certainlycould have more of a downward run before it goes vertical. I live in a council flat, 3 flights up.
I will clean the overflow pipe as well.
Could this smell be coming from the washing machine drain hose, which is teed in just under the sink drain, but above the waste trap.
The smell seems to go away after the washing machine has been used.
In relation to the concentrated bleach. I take it this won't harm the sink or pipes etc.

 

[simon]

The washing machine should pump out the waste water followed by a flush of clean water to prevent any smells so my money would still be on the waste pipe not dropping enough.Is it some sort of new installation or have you moved / changed something that has triggered the problem?

 

[breezer]

Have you changed brand of soap powder or conditioner for your washing m/c lately? ( ie shops own brand) belive it or not this can cause smells. The other thing to check is the connection from your washing m/c to the T piece, if the w/m pipe is connected to a "push on" connector on the waste pipe sometimes fluf etc gets caught at the join or inside and causes a smell, it is worth looking at. And no domestic bleach will do no harm to the pipe work.

 

[pappyon]

There have been no changes of any kind. The kitchen plumbing has been the way it is since we got new kitchen units including sink unit etc put in about 7 years ago.
the only change is a new (over a year ago) Hotpoint Ultima 1400 washing machine, but I just put the waste hose on to the same connection as the previous one. I will check this for any build-up of fluff, gunge etc as advised
My better half always uses the same branded washing powder. I don't know about conditioner, but will ask her.

Thanks again for response. Much appreciated

 

[emailrob]

Ensure the waste pipe for the washing machine is at a high enough gradient. I had the problem whereby the waste from the washing up bowl was going back up the waste pipe of the washing machine, which made a lot of smell. Mine was actually blocked with grease and gunk from the sink.

Hope this helps.