Water pressure in new buildings - standard and possibilities for improvement?

No, I don't think so. Lime rarely comes out of the tap as stone. And that would hurt too.

But you can also reduce detergent and dishwashing liquid.

Familiarize yourself with the topic of water hardness and the dosing of cleaning agents.

How strong is the softening set? Have you ever used a Rainshower before? Maybe try using a simple handheld shower from the hardware store as a comparison. The Rainshower is "fine-pored" and compensates for that with flow rate ...

Did you previously live in an old building? We often receive complaints about insufficient water pressure when constructing new apartment buildings. Upon inquiry, it often turns out that the connecting pipes used to be dimensioned twice as large, but nowadays they are, of course, only designed according to demand due to water quality. This naturally results in much less water flow at the tap point.

And you usually notice this either with the rain shower or when filling the bathtub.

An inlet pressure of 4-4.5 bar is sufficient for an apartment building with 3-4 floors, by the way. So it definitely can't be the inlet pressure.

An inlet pressure of 4-4.5 bar is sufficient for an apartment building with 3-4 floors, by the way. So the inlet pressure is certainly not the issue.

A static pressure of 4 bar is definitely sufficient. The static pressure is, of course, independent of the pipe dimension. However, in the case of the original poster, the pressure drops by 1.5 bar, and this pressure loss is far too high. This indicates a cross-section that is too small before the measuring device, or a valve that is not properly opened.

No, I don’t think so. Limestone rarely comes out of the tap as stone. And that would also hurt.

But you can also reduce detergent and dishwashing liquid.

Have a look at the topic of water hardness and dosing of cleaning agents.

I will!

How strong is the softening set?
Have you used a Rainshower before? Maybe try a simple hand shower from the hardware store as a comparison. The Rainshower is "fine-bubbly" and compensates that with flow rate...

We specifically took the old shower from the rental apartment and connected it – same result. Much less pressure.

Did you live in an old building before? Here we often have complaints about too low water pressure when new apartment buildings are built. When asked, it often turns out that the supply pipes used to be twice as big, but now they are of course only designed as needed due to water quality. That usually results in much less water throughput at the tap.

And you notice that either at the Rainshower or when filling the bathtub.

An inlet pressure of 4-4.5 bar is sufficient for an apartment building with 3-4 floors, by the way. So it certainly can't be the inlet pressure.

Old building is correct – built around 1870 or so... but on the first floor. I still have access to the old apartment and also to the water house transfer point. I’ll check that. You should be able to tell at first glance by the "big pipes," right? The hot water was prepared on demand in our apartment via a gas boiler ("floor heating"). A kind of instantaneous water heater...

I only knew Rainshower from hotels before, where there was always much more power behind it. In my opinion, that’s exactly what makes it appealing to stand under pouring rain...

A static pressure of 4 bar is definitely sufficient. The static pressure is, of course, independent of the pipe size. But in the OP’s case, the pressure drops by 1.5 bar, and this pressure loss is far too high. That points to a cross-section that is too small before the meter, or to a valve that hasn't been fully opened.

I just checked again: all valves I can see are fully open. The pressure drop when drawing water is about 1.2 bar, apparently I looked at the gauge wrong last time.