Discuss Bath tub drain smells - Getting blow back from drain? in the Bathrooms, Showers and Wetrooms area at PlumbersForums.net

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Hello All,

I have an issue and hoping someone could shed some light on the problem.

We have been getting a smell coming up in the bathroom, initially thought it was the toilet, but after smelling the bath tub plug hole it appears to be coming from here. I removed the P trap and very little water was in it and my wifes hair had be lodged in it, which i believe aided to smell. BUT i noticed something weird that i am not sure if its meant to happen or not. The main bath tub drain pipe is blow out a slight cold breeze / air so if you connect the p trap you feel it through the sink hole, or if you remove the P trap you feel from the drain pipe (see video: View: https://www.youtube.com/watch?v=ajdTkxQWt2s
: Is this normal hence needing the water in the P trap or is it another issue of concern? 2015 New build home.

Thanks again in advance
 
Wouldn't overly worry about a slight breeze. That's normal. If your trap doesn't form a water seal that would cause a smell. They can dry out, but unlikely if used regularly.

The water can be siphoned out by a blockage further down the system, which will cause an issue and smells. Then there is the overflow, which can sometimes trap bits of waste etc and cause smells. This is above any water seal so won't be prevented by the water seal.

If everything is clean and a water seal you should have no smells. A slight breeze is unlikely to blow the water back out the plug hole. If it was gale force, you could get an alternative trap with a seal preventing return flow, but that is very unlikely.

Hope this helps at least a little.
 
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That is a very shallow seal trap , which actually should not be used when connecting to a soil and vent pipe ( but it often gets used)
If you fit a p-trap with a deeper water seal you won’t get smells coming back up the waste (may need to cut out a bit of floor to accommodate the trap).

However in your case I think that the smell is caused by water sitting in the overflow corrugated tube as this is too long and bends down to form a trap which will be full of stale water, soap/skin residue etc.

Remove the overflow tube from the waste fitting and shorten the tube by a few inches so that it forms a smooth continuous bend from overflow to waste. Give it a good clean out whilst you have if removed.
 
Hey guys,

So I took in your advice, it does seem it was just due to the p trap water evaporating. But I took the advice and reduced the overflow pipe length. I thoroughly cleaned out all the pipes and rand some baking soda and vinegar down. Bad smells gone. Thanks again for the help really do appreciate it.
 
Hey guys,

So I took in your advice, it does seem it was just due to the p trap water evaporating. But I took the advice and reduced the overflow pipe length. I thoroughly cleaned out all the pipes and rand some baking soda and vinegar down. Bad smells gone. Thanks again for the help really do appreciate it.
I am glad that you got rid of the smell :)
 

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