Smell from bath drain

[ygavan]

I hope I am posting in the right forum!

Over the last couple of months I have got a really horrible damp smell from the drain in my bath. I have checked under the bath and it is bone dry so no water is leaking anywhere in the bathroom to cause the smell. When I close the plug whole, smell disappears so it is definetly coming from there. Any ideas what could be causing it? The water drains away without any problem so there doesn't appear to be any sort of blockage.

 

[JPC]

i take it the bath trap (underneath the bath) holds some water

is the waste pipe connected to another waste pipe before going in the soil stack/ hopper

if u poor some water in the bath and let it run out ( dont use any other bathroom stuff) can u see the water in the trap (this is a seal agaist air coming back up into the bathroom)

 

[jobloggs]

There should be a u shaped trap full of water below the bath outlet. Unfortunately bath traps are shallow and may become empty of water due to syphonong effect from basin or toilet flows or if bath is not used for a long period. This lets smells from soil pipe/sewer back into bathroom.

You could try fitting a deeper trap to bath if you can cut a hole in floorboards you accomodate it.

Failing that: If you don't regularly use the bath (no reflection on your hygene, some people prefer showers) run the bath tap for a couple of seconds at regular intervals to fill up the trap.

 

[JPC]

or just keep the plug in place !