Stink under kitchen sink

Crumble2018

We moved into our flat 6 months ago and have had a bad smell from the under sink cupboard on and off since. We’ve always treated it with disinfectant which helped for a bit, but now it’s got really bad and persistent. We’ve run a washing machine cleaner and tried every remedy we can think of but it still persists. 
The pipe under the sink looks a bit weird in that there’s one with an open top? My husband took it off and cleaned it,  but it’s got worse if anything. I’ve attached a photo of the pipes and you can see the open one at the front. We don’t even know where it comes from or what it is. Should this be capped? Any other ideas?  Thanks!

slipthru

The open pipe is a stand pipe used for a washing machine waste pipe. I assume you already have it connected to the waste pipes on the sink traps though. No idea if it should be covered.

nofoollikeold

1. If no water ever goes down that standpipe, the U bend at the bottom will dry out and let drain smells in.
2. Either:
2a. Regularly pour a jug of water down it (once a month in winter, perhaps once a fortnight in summer).
2b. Cap it.

Mutton_Geoff

nofoollikeold said:

1. If no water ever goes down that standpipe, the U bend at the bottom will dry out and let drain smells in.
2. Either:
2a. Regularly pour a jug of water down it (once a month in winter, perhaps once a fortnight in summer).
2b. Cap it.

The U bend should contain water to act as a trap. Without that it will emit smells from the sewer. As well as drying out, it's more likely to get siphoned out very time you pull the plug on the sink.

Cap it either with the proper fitting (see below) or a couple of bits of duct tape.

https://www.screwfix.com/p/mcalpine-t23u-multifit-blanking-plug-white-40mm/96079

Crumble2018

Thanks all. We now have a pic of our neighbours pipes, and it seems we connected our washing machine to the outlet for a dishwasher - my neighbours washing machine goes directly into the open pipe!  
Would we be better doing this and blanking off the dishwasher drainage again, or just blanking the open pipe we already have?

TELLIT01

Rather than faff about moving pipes, I would simply cap that one off.

Crumble2018

Thank-you everyone.  We have covered the pipe with duct tape and smell is gone! Will get a proper cap for it later this week.  Feel a bit silly for being so clueless 🙄

shaun_from_Africa

Crumble2018 said:

Feel a bit silly for being so clueless 🙄

Don't.
Even expert plumbers were clueless until they learnt their trade.