How should water pipes be laid

When I look at it like this, all my alarm bells would have gone off.

Unfortunately, this construction is very poorly thought out, I suspect mounting holes above the connections would have been less problematic.

But now it's too late to complain, let it be a lesson for you and I hope you don't have another guest bathroom with the same panel :)

Fortunately, our plumber installed the rain showerhead that we bought ourselves for a small fee. Because I really wouldn't have been up for that kind of hassle.

That has nothing to do with cheap construction, but is standard and is actually always done that way. It was the same 30 years ago. However, the shower panel is actually extremely poorly designed. The designer should actually be punished for providing the drill holes that way.

Normally, a plumber must ask which toilet model, which urinal, what kind of bathtub, and which fittings are being installed. Only then can they adjust the correct heights on the concealed cisterns for the toilet and urinal according to the data sheets, determine the correct position of the drain before the screed for the bathtub, and provide the right bodies for the fittings.

This is one of the reasons why many sanitary installation companies decline when customers want already purchased bathroom fittings (e.g., bargains from the internet) installed.

Sanitary installation companies often make mixed calculations. Since customers are unwilling to pay the hourly rate (except possibly in the case of an insurance claim), many installation companies try, if not to sell the installation work, then at least to sell the work with materials.

The person who is allowed to install the fittings is also the contact person for broken tiles, scratched bathroom furniture, and leaks, with the argument that everything was fine before. It is often overlooked that the tiler may have installed hollow tiles, the pipes were not laid properly, or the bathroom furniture was damaged during shipping or unpacking.

Normally, I can assume that pipes are laid vertically, at least that was always the case in older apartments, but that is exactly the problem with today's house construction: fast and cheap, cheap labor or people who don't feel like chasing two grooves. Unfortunately, I couldn't take any pictures because I took over the turnkey house from the developer. The shower panel we wanted to install is from Hans Grohe and the holes are just below the outlets.

No, normally you cannot assume that...what was done 20-30-40 years ago no one cares about nowadays...

And before drilling anywhere, you have to determine where the pipes run, that is also common practice...otherwise you should not drill.

That has nothing to do with motivation...they do what was ordered...if water in the shower was ordered once, then there is water in the shower...according to the state of the art, that is in one groove.

This was done differently in the past during the steel pipe era only because it couldn’t be done otherwise. The pipe couldn’t be bent like that. However, I find it poor that they now want to blame the installer for it. You should have informed yourself beforehand on how this is done nowadays. Or had it done like the rest.