Smelly sink - critique this plumbing.

[Badda]

Our washing machine is in our utility room which also has a small sink. You can hopefully see how this has been plumbed in with the photo.

Over the last couple of months, when the washer starts draining there s a nasty smell coming up from the sink. We ve tried everything from boil washes, bleach etc but it comes back regularly.

Can someone better than me at plumbing tell me what the builders have done wrong with the pipe work please. I m sure the washer should be draining the other side of the u bend?!

[GiantEnemyCrab]

Is water sitting in the small U of the grey pipe after the pump finishes? Can you make it have a constant fall perhaps?

[Badda]

I’d not considered that. That’s an easy test. Thanks.

[98elise]

Badda said:

Our washing machine is in our utility room which also has a small sink. You can hopefully see how this has been plumbed in with the photo.

Over the last couple of months, when the washer starts draining there s a nasty smell coming up from the sink. We ve tried everything from boil washes, bleach etc but it comes back regularly.

Can someone better than me at plumbing tell me what the builders have done wrong with the pipe work please. I m sure the washer should be draining the other side of the u bend?!

No its meant to be that side of the trap so that sewer smells don't make their way into your washing machine.

Ours also smells occasionally but a maintenance wash gets rid of it.

[Promised Land]

98elise said:

No its meant to be that side of the trap so that sewer smells don't make their way into your washing machine.

Ours also smells occasionally but a maintenance wash gets rid of it.

I think Giantenemycrab is referring to the dip in the horizontal run above the sink trap.

Stale water will sit along the lower part of the pipe until the next wash cycle pushes it out to the trap U bend, then you’d get the smell up from the plug hole.

[bennno]

You need to get an inverted u bend on the washing machine pipe and it needs to be kept much higher up, or sink will partially empty in to it.

[98elise]

Promised Land said:

98elise said:

No its meant to be that side of the trap so that sewer smells don't make their way into your washing machine.

Ours also smells occasionally but a maintenance wash gets rid of it.

I think Giantenemycrab is referring to the dip in the horizontal run above the sink trap.

Stale water will sit along the lower part of the pipe until the next wash cycle pushes it out to the trap U bend, then you d get the smell up from the plug hole.

In the OP he asks if its the right side of the trap, so I was referring to that.

Giantenemycrab is correct that water is probably getting trapped in the pipe.

[Badda]

Cool. I shall make amends to the pipe so there’s no slight U and see what occurs. Thanks all.

[bennno]

Badda said:

Cool. I shall make amends to the pipe so there s no slight U and see what occurs. Thanks all.

Don’t do that, do as I advised you. It needs to loop up towards almost the height of the sink

See here

https://community.screwfix.com/threads/can-you-spo...

Ideally you should use one of these

https://www.ebay.co.uk/itm/394381680582?chn=ps&amp...la-2361954446071&abcId=10027104&merchantid=7254194&gad_source=1&gad_campaignid=21701214154&gbraid=0AAAAAD_Lr1eW9E3Fk275uF2pB9uvXv1Gc&gclid=CjwKCAjw6vHHBhBwEiwAq4zvAxDEvk4OrLvSuiss46ejwIaliR81BvXH0ymhfIr74Y_cn1apdmCk5RoCxSUQAvD_BwE

[craigthecoupe]

It's already as high as the sink, see where it comes through the rear panel of the unit. I think the idea is to have a smooth fall into the sink plumbing from that point, rather than the small kink in the grey pipe, which presumably holds a small amount of waste water from each wash cycle.