Water and beer

Below 5 dH is the perfect water hardness to brew most types of beer in Germany.

By the way, the water hardness in Munich is a lot higher with over 13,6 dH. Therefore, the Munich breweries have deep wells where they can reach softer water, like Giesinger Biermanufaktur & Spezialitätenbraugesellschaft mbH did 2020. Their well is around 150m deep.

Sources: https://www.hopfenhelden.de/bierwissen-craft-beer-brauwasser/

https://www.swm.de/wasser/wasserqualitaet