Smelly bathroom

[GlitteryPink]

What can I do to stop the horrible smell in my bathroom? Every now and again after I turn the taps on a horrible smell comes up from the plughole. What is causing this and how can I stop it? I don't think the pipes can be blocked because the water runs away normally.

[stanleyman]

There could be a problem with the drains that are not venting properly or it might be stale water in the overflow. Try some bleach down it to see if it makes a difference.

[jon1968]

I once had a tiny leak in the U bend in the bath in my my spare bathroom - needless to say the smell was awful when I did go in there! I can't understand why yours only smells if you turn the taps on though unless the flow is somehow affecting the airlock effect of the S or U bend?

[jon1968]

Sorry, had to start the video! Does how fast you turn the taps on determine whether it smells or not as it may be that a fast or slow or medium flow would compromise the airlock - theoretically it shouldn�t be able to, but it can (I�ve had it happen) and you�ll get a whiff of whatever is in the outside drain.

[Robinia]

I'd agree with stanleyman about the overflow. Soapy water can cause a buildup & make it smell fusty. Trickle some bleach down it & leave it for an hour & then flush with clean water. You can buy a very narrow brush on a bendy wire for keeping it clean too.

[curiosity]

I had this problem in my kitchen, always when I ran water, not at other times. Bleach helps, but only short term. I unscrewed the grey U bend bit, just underneath and gave it a good wash. Hair etc can start to clog in bathroom sinks, or if someone has happened to be sick in it (sorry) anything really can be in there stagnating. These Mr Muscle type sink and drain unblockers that foam when you put them down also help, but they are commercial and seem a bit of a rip off, someone might know a better home or trade remedy. Once sorted, a regular bleaching might help, and a hair catcher thing from the likes of Betterware.

[lilacben]

Hi put a lot of soda crystals down the plug hole and pour over boiling water. this will help clean the pipes.I also use this for my sink about once a month. There is a Mr Muscle foamer you can buy which is very good, but to be honest I think this may be soda of somesort anyway and a lot more expensive.

[buildersmate]

The reason why it is doing it probably because the flow of the water down the waste pipe AFTER it has flowed past the U bend but before it reaches the main vertical stack pipe is syphoning out the residual water that is supposed to remain in the U bend at the end of drainage. This is then compromising your water trap and there is a direct air flow between the sewer and the plughole. This can either be a design problem with the waste system or narrowing (partial blockage) in and around the U-bend. If it has only just started doing it then it is the latter and I agree with the ideas above for removing the problem that is causing it. A design problem would be created (for example) when the slope on the waste pipe after the U-bend is excessive - causing the water to rush through, creating the syphon effect. If caustic soda doesn't stop it there is a way to stop it without pulling the pipes about too much. It involves fitting an air admittance valve in the pipe line just after the U-bend. These things let air in but won't let air or water out, and it breaks the syphon. I have seen combined traps with an air admittance included in the design and this would be the easiest way for the DIYer to implement. Take the old one off when you visit the plumbers merchant to show them.

[jon1968]

To add to Buildersmates excellent answer, my problem was caused by a monobloc mixer which was directly over the plughole, it�d be fine on a slow or fast flow (because it�d miss the plughole) but medium flow caused the whiffyness! As it was obviously caused by the flow compromising the airlock I tried a diffuser on the tap head but that didn�t work but fortunately the pipework layout meant I was able to simply replace the U bend with an extendable bottle trap which solved the problem. Don�t know if this would be applicable in your case though.