Munich

Munich water is moderately hard, with relatively high bicarbonate. That's significant, because bicarbonate buffers acid, and dark malts are acidic. The two balance each other out. This is why Munich became the home of dark lagers: the water and the malt were made for each other.

In a pale beer, this level of bicarbonate would be a problem. It would push mash pH too high, making extraction harsh and astringent. But dark, heavily kilned malts bring enough acidity to pull the pH back into range. The result is a smooth, malt-forward beer with none of the sharpness you'd get from the same water with a lighter grain bill.

Munich's mineral profile suits Märzen, dunkel, bock, and schwarzbier. If you're brewing anything where rich malt depth is the point, this water helps you get there. It's not a profile for hop-forward styles, but that was never Munich's thing.