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How to Resolve Weird Stinky Drain and Shower Waste Issue

Postby kaylajane » Fri Mar 11, 2016 10:14 am

Good Morning

I wonder if anyone can help.
I moved into a property in December, which has an intermittent sewage smell coming from the shower in the bathroom. I had DynoRod out and they said that it was the waste pipe from the shower, as its one of those flexi types, fitted with not enough downward gradient.
Rather then rip the bathroom apart at the time we held off as we will shortly be putting a new bathroom in and scrapping the shower.

Last night there was another sewage smell, in the kitchen (directly underneath the bathroom). The soil pipe is boxed in behind kitchen cupboards. I opened the cupboard where the washing machine lives and the smell was even stronger. I shone a torch into there, as the soil pipe isn't blocked in under there as the washing machine waste is linked to it. I couldn't see any signs of a leak. The smell has gone again this morning.

I'm not sure on what to do now. The smell comes and goes, there is no sign of a blockage as everything drains as it should, the only unusual thing is when you flush the upstairs toilet, it creates a suction noise in the shower.

Is it worth getting someone out with a camera? Not sure what they'd be looking for. I've read lots of articles on the soil pipe vent, but I don't no where this is, I cant see that the pipe goes any higher then the bathroom (the pipe is under the bath)

Sorry for the long post and thanks in advance!
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Simply Build It

Postby thedoctor » Mon Mar 14, 2016 9:43 am

The suction noise in the shower is the clue here.

All wastes have a water trap in the shape of a U bend of some kind. The water sits in this U and stops any gasses getting back down the pipe to the shower/bath/toilet bowl/sink etc. We have several pages on the website about how wastes work and how to fit them. Here is an example

A vacuum is created when a toilet is flushed or water is let out of a basin or bath. As the water rushes down the pipe it creates a vacuum behind it. This vacuum can sometimes be strong enough to leterally suck the water out of the U bend. Without any water in this bend, foul gasses can get back up the pipe.

The gurgling and sucjing noise you can hear is the water being sucked out of the U bend.

This can be overcome by inserting an air adittance valve into the basin/shower pipework and instructions for this can be found here ... valves.htm and here

Good luck and please do let us know how you get on.
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