Rainboe,
Yes, I'm not too keen on drinking water from the tanks although, when I think about it, we used to drink water from our ships tanks at sea.
On some sail trainers we analysed for free chlorine in the potable water tanks and adjusted with tablets.
The problem with the aircraft tanks is that, even as crew, we don't get to confirm the treatment.
Re food, at least we could take on something that we like to eat - and the dabbawalla could bring the skipper's tiffin from Mrs Pilot