This is germany. We dont have contaminated drinking water. Drinking water is the best controlled nutrition in Germany. We have good filtres and cleaning technology.
We're happy that you see it that way. Where did you get your info?
Read the Trinkwasserverordnung.
Trust me. Tap water is the only "food" that they check every hour/every day for the quality. You dont need to buy bottled water here.
There are even a lot of cases that they found out that the bottled water has a worse quality then the tap water. The tap water is the best here. (seriously)