Stinky sink - incorrectly fitted trap?

[danb77]

Hi all,

I am suffering with sewer gas coming from my sink when it drains. I live in a block of flats and need to find out if the problem is my plumbing (my responsibility) or the drains (management company's responsibility).

I had the trap replaced recently, which did not solve the problem. Looking at the p-trap I am concerned that the horizontal arm is very short and that there is no vent.

I attach an image. Does it look like my ptrap was incorrectly fitted?

Other symptoms: My washing machine drains via this ptrap as well. When it drains, the sink gurgles and water often rises from the washing machine through the plug hole.

Does all this sound / look like a problem with my pipes or a problem with the drain venting?

I'd be very grateful for any help.

Untitled

• danb77
• 31 Jul 2014
• 1

Untitled

• danb77
• 31 Jul 2014
• 1

 

[buck51]

Its backing up because you have a blockage, between the trap and the soil stack

 

[danb77]

Thanks. I hope it is that. That sounds easy for a plumber to fix.

Would a blockage cause the sewer gases to leak out when the sink is flushed? This is why I thought it was a venting problem. Can a blockage disrupt venting?

 

[fluxeyfingers]

A blockage could count as a sagging pipe holding water, causing a double airlock.

 

[danb77]

Thanks. I will get a drain specialist to come and take a look. It is reassuring that the ptrap is not the problem.

 

[fluxeyfingers]

One test it may be worth doing is to pour bleach down the overflow, if the overflow is manky. If it's icky inside it can release a blast of 'sewer gas' when you pull the plug. But the fact your washing machine is backing up points to a blockage downstream.

 

[danb77]

Thanks. I have given the overflow a good flush, but I don't think it is the issue - it rarely (if ever) gets used.

The sewer smell comes in a single "gust" shortly after the last bit of water has drained from the sink - it is this which makes me think the trap is syphoning.

Update: After flushing the overflow hole with a *lot* of toilet bleach, the smell seems to have gone away. Maybe masked by the smell of the bleach, but I'm not smelling it right now. Absolutely great suggestion!

 

[Servotech]

It's your washing machine - put some "Dr Beckmans" through it on a 90 degree wash cycle.
servotech,

 

[danb77]

Thanks. This is good advice too.

It is looking like the overflow was the main culprit here, but when I cleaned the filter of the washing machine the filter did have a bad "drainy" smell. A boil wash is a good precaution.