How does one idiomatically order water at no charge at restaurants in Germany?
In at least US and France, an order of water, qualified if necessary to clarify as just water or regular water, will usually produce glasses of water and/or a pitcher of tap water that the customer is not charged for. In US English and in French, idiomatically, it is not usually necessary for the customer to specify that they want tap water or that they want water at no charge, and it may even be considered somewhat improper to make such an explicit clarification.
The naïve translation of these expressions into German (e.g. nur Wasser or normales Wasser) has not worked for me in practice (waiters invariably bring bottles that they charge for).
What is the idiomatic way to express, in German, that one would like no-charge water service for the table? Or is that something that restaurants in general do not provide?