Stale smell coming from shower drain

[finchfinch]

Hi,

We are getting musty smells coming from our en-suite shower drain. I'm no expert but I believe that the water is drying up (or being pulled from the toilet) in the p trap which exposes the sewer gases.

I put my nose directly over the drain and the gases hit me in the face. I'm concerned because I know these fumes can be extremely harmful to health.

A few things to note:

1. The smell instantly disappears when I have a shower. After a shower, the en-suite won't smell for the best part of a day, but after around 6-8 hours the smell returns (the shower does not get used during this period).
2. When I flush the toilet I can hear water gushing around from the shower drain (don't know how relevant this is, but thought I'd keep this here for the pros).

Are my initial thoughts about water drying up from the p trap correct? Or do I need to get some baking soda/vinegar down there? (I'm afraid this will only make it worse).

I've been reading similar sorts of issues online, but people don't really address this particular scenario head-on. What are my options? Is it a case of just topping the shower up with water twice a day and carry on living life as normal? Or can this actually be corrected somehow without ripping the en-suite apart? Appreciate your guys support and experience.

Many Thanks,

 

[opps]

If there is a slight blockage in the soil pipe/drain, when you flush the loo it can create a vacuum and suck the water of out bath/shower/basin traps.

It is very, very unlikely to be down to evaporation.

As a test, each time you flush the loo, pour a cup of water in to the shower. I suspect that you will have no nasty smells if you do that.

 

[finchfinch]

Hi, thanks. When I flush the toilet the shower drain doesn't smell. If I shower in the morning, and don't revisit the en-suite all day, it will start smelling in the evening time. We have 4 toilets in the house in total, so I'm not sure if toilets on the floors below (It's a townhouse, ensuite is on the 3rd floor) could be contributing to this problem. Either way it sounds like the lack of water (whether it's being sucked out or otherwise) is causing the issue. We do have a slow draining sink in the kitchen at the moment (1st floor), so I don't know if this blockage could be linked to the shower drain smell? We are hoping to resolve this kitchen sink issue next week as someone is coming to take a look.

 

[opps]

It may take more than a total of two flushes to suck out enough water to let the sewer smells past.

 

[finchfinch]

I'll do a few tests and monitor it. If we assume a few more flushes will expose the smell again, is it a case of trying to address this potential block? If so, is baking soda and vinegar/boiling water down the drain my best bet?

 

[opps]

I would lift the manhole cover and get someone else to flush the loo to begin with.

That said, I am not a plumber. I am just an old git that has worked in many, many houses and come across numerous issues, some of which I resolved and some of which I recommend that the customer to get some one to sort out.

I have however come across your problem before, and a plumber rodding the soil pipes sorted it out.

Hopefully a proper plumber will be a long soon.

Best of luck.

 

[HERTS P&D]

Some shower wastes need to be clipped into place to create an air tight seal.

Andy