Our hotelier charges 1euro for a glass of tap water. I have no idea if this normal practise in German restaurants/hotels but it surprised some in our group.
Have something else instead - like tea. At least you know they have had to heat the water up first!
Our lovely hotel was situated VERY close to the railway line which runs along the banks of the Rhein. The lines also run parallel on the opposite bank and the sound carries quite clearly. This was quite a problem at night because the trains seem to be even more frequent in the early hours. They are mostly freight trains and they are often 20-30 wagons long!
This really was the only disadvantage of our hotel - if it wasn't for the noise it would have been almost perfect!
The photo is one of the passenger trains that travels through Bad Salzig on it's way to Koblenz.