where to find the water shutoff valve of my apartment?

I am renting a flat in Lausanne, and I want to install a small washing machine in the bathroom.

I don't want to tell the proprietary of the building about it (i know i should).

where to find the water shutoff valve of my apartment?

i've looked around the bathroom sink, everywhere inside the apartment, also outside in the floor...

is it common in switzerland to have an individual water shutoff valve for every apartment, or they only have one for all the building?

Depends. If you want to tap in to the bathroom sink there is as normally a cover on the pipe coming from the wall. Remove/unscrew the cover, then you can close a valve using a screw driver.

Thats should normally do the job for tapping in.

If that should no be the case, which would be very unusual, the shutoff valve is somewhere downstairs in the basement. Hopefully in a non locked room. Sometimes there is just one valve for the whole building.

Sounds like a good way to get evicted in one easy lesson. If you think your neighbours aren’t going to notice and complain you don’t know Switzerland.