Why does my new shower smell?

[MaisieDobb]

Hello!

We recently completely renovated our house - essentially tore it apart and rebuilt the inside. One of the new showers in our attic conversion consistently has a horrible drain-like smell coming from it. I run the shower everyday which helps a tiny bit at the time but a few hours later the smell is fully back. It’s in my children’s bathroom so not actually used (I’m only running it to try and prevent dry traps and stop the smell) and it doesn’t seem to have any issues with slow draining

Any ideas what the issue could be?

Have you run some pipe unblocker through it? Does it have a drain cover plate and if so have you taken that off? We had a sink that was trapping soap under the push button of the plug and then attracting hair and all sorts and if essentially rotted into a big mass of mould under the plug. Took us ages to work it out!

Do you have a macerator toilet in the same bathroom? We have a terrible en-suite from previous owners, the sink drains into the of the plumbing of the macerator toilet. So you get the toilet sewage smells coming up the plug hole, particularly if you run the taps for a long time. My other suspicion being a loft conversion is that the pipes are maybe not at steep enough angles, or are too narrow, so the water doesn't drain efficiently.

If you lift off the cover of the shower drain does the plastic piece below come up too? I find that the plastic piece has to be pushed in really firmly. The rubber seal around the edge should make it form a tight fit into the top of the drain. If it comes loose we often get a bad smell but if it's pushed back in the smell goes away.

if it smells eggy be careful it's not anything to do with the electrics X

It definitely isn’t build up of hair as none of us have actually used it (kids are still young so always have baths), and no macerater toilets.

I’ve taken the cover off and you can see clear water in the drain pipe which looks clean BUT air bubbles keep coming to the surface on a regular basis. Do you think this means there is a leak somewhere or is this normal?

Fit an anti siphon trap. Large amounts of water, usually toilet flushing can sometimes suck some of the water from the trap. It may be sink if you have one, rather than the shower. We had exactly this problem in our 3rd floor En-Suite

I thinbk bubbles coming up in a still drain is abnormal, maybe a blockage somewhere in the drainage system.
We had this from our bath and it was because the soil pipe was blocked (eventually got to the point everything was blocked-luckily coincided with building work involving removing and relocating it)
Also used to get from our ensuite sink (different soil pipe) and bubbling through the shower drain when ran the tap-a good plunging seemed to shift all the crud in the drain and it's better.

Might be worth trying boiling hot water, then bicarbonate and white vinegar then more boiling water.