The water is fine, but the sink usually isn‘t. The sinks are just as contaminated with bacteria as the toilets themselves —- sinks in really busy restrooms are constantly damp and allow bacteria to grow more than one would expect.
You're not drinking from the sink though, but the tap. The tap is also constantly wet in every house and we're never cleaning inside it. On the other hand, my kitchen is not getting cleaned with heavy antibacterial chemicals multiple times every day.
Are you sure the taps in commercial restrooms would have more bacteria?
From one Hamburger to another...just where, please?
I could swear I saw a drinking fountain once, somewhere along that long corridor connecting the gates but I never found it again and, to this date, I've never drank from it. (I mostly fly Eurowings to other Schengen destinations.) If it really exists, I'm sure there is only one such station past security, or maybe one per airport wing.
And look, in a pinch I'm ready to drink tap water from the airport toilet faucets. I'm ready to entrust my life to that dice roll. But, as a matter of human dignity being inviolable and all that, I would much rather shell out money for an expensive bottle of water.
The bigger joke is that the vending machines in an international airport only accept euro and no credit cards.
Maybe this changed since I have moved from hamburg to Stockholm 2 years ago. But the hamburg airport compared to Arlanda is a joke.