Came out of the shower on the ground floor

Hello everyone,

I have a shower on the ground floor. Unfortunately, after a day it starts to smell bad. In my opinion, this happens more often in winter (when the underfloor heating is on, but well).

The only thing that helps is to turn the water on in the shower again and let it run for 2 - 3 minutes, which I find a lot.

When I turn on the washing machine in the next room, it also, in my subjective feeling, causes the smell to come back.

Does anyone have an idea what I could do? Unfortunately, I have no more ideas. I have attached a few photos.

I'm not a plumbing expert, but as I understand it, the end piece of your stopper, which you are holding in the third picture, should always be submerged IN the water at the bottom. However, you have either too low a water level or a stopper that is too short, which is why the end piece is hanging in the air and sewer odors come through unhindered.

This naturally occurs more when the heating is running because the water evaporates faster. The connection with the washing machine could only be explained by the fact that when it pumps out, the resulting vacuum (no or insufficient ventilation of the wastewater pipe?!) causes your shower siphon to be sucked dry.