Separate water meter for the external tap point - connection

With us, it is worth it because we only have to pay for the meter, nothing more. No fee or anything like that

That's strange though...usually the water suppliers want their piece of the pie. I would do some more research.

I can confirm ... you have to rent the sealed meter, then you pay the plumber

What do you need the plumber for?
Apparently it varies a lot. Here, you can get the meter yourself (€30), screw it on yourself, and call the water association. They seal it and record the readings. From then on, you pay a €6 annual fee. After 6 years, the calibration expires. Then you start over.
We have had the meter for 1.5 weeks now and have used about 10 cubic meters during this time because we laid new lawn. So far, we have already saved €28.50 in wastewater fees. In a few days, the investment will have paid off and then it saves money.

Well, it varies greatly,

here is an excerpt from the Berliner Wasserwerke:

We can only recognize private meters if they have been installed by a company registered in the installer directory of Berliner Wasserbetriebe. A list of our contract partners can be found on our website.

That's strange...usually the water suppliers want their slice of the pie. I would look into it again.

already done, they don't want anything. A photo of the meter sent to the city is enough and the meter reading in August

Well, it’s just very different,

here is an excerpt from the Berlin Waterworks:

We can only recognize private meters if they have been installed by a company registered in the installer directory of the Berlin Waterworks. You can find a list of our contract partners on our website.

exactly for that... it was similar for us... apart from the fact that I don’t want to do anything alone with water and electricity anyway.

we would have had to have the waterworks show up every 5 years, then also read every 2 years, etc.

as I said, it was not worth it for us