Tap water? I hope this is not the water from the faucet in the toilets onboard. Or is tap water here the water from the filter system that the crew uses to make coffee/tea? [I thought that for this, they have the direct hot water from the galley].
In any case, I'm also someone that avoid BA ET as much as possible and if I do have to, I bring my own onboard.
Will have to try that the next time - to ask for a non-bottled drrinkable water.
Cheers!