Kalkriesel as if I were at the beach

Hello, we have been living on the left bank near Cologne since April 2013 in our new end-of-terrace house. After a relatively short time, we noticed that the water pressure on the first floor noticeably decreased in the shower. So, unscrewed the shower head, removed the sediment, and moved on. That would still be okay, even though I have never experienced such a rapid buildup of limescale. However, in the last few days, I have had to empty the shower head a few times during showering just to be able to shower at all, and not just get clots coming out. You can also really feel the limescale sediment on your feet in the shower tray, as if you had just come from the beach. I suspect it is limescale, looks whitish like sand. But I haven’t proven it with vinegar yet. The row of nine houses has a shared heating system at the end of the row. All the others don’t seem to have this problem as badly. Am I just unlucky here or was something botched somewhere?

The problem falls under warranty, the company should take care of the repair. No one here in the forum will be able to help. Without knowing your technical equipment, one can only guess. At least it doesn't calcify that quickly. We have/had water hardness of 20 and even then you had about half a year of peace before the shower head had to soak in vinegar water overnight. I would exclude construction dirt after 6 months now. We have a filter on the water inlet that filters out solids. If that is broken, sand can get into the pipe. Otherwise, really no idea. A professional has to take care of it here. :)

Both construction companies and plumbing companies deny all blame and refer to the hard water in Cologne, saying that unfortunately nothing can be done about it. So I’m left standing there looking stupid. Who should I turn to so that someone can clearly tell me what is possible and what is not? Maybe also with a view to the system, a lawyer and/or an expert?

If you are sure that it is not limescale, you will probably have to get an expert. How hot is the water coming out of the showerhead? Do you shower very hot? Because the warmer the water, the more limescale precipitates. What if you replace the showerhead? There are already cheap ones for 10 €. Does the problem then occur again so quickly?