Still incredibly responsible to give flower bottled water, they will happily have tap water.
I do own a water butt, but it's been empty for weeks. I don't drink the tap water where I live, it smells like a swimming pool, so just use bottled water anyway. I'm just doing it at the moment, what with the lack of rain. I reuse the 5L empty bottles to stock up on rain water from the butt.
Probably doing more damage than good with all the empty water bottles! cheaper and better for the planet including the bees to get a water butt. Seriously though even if you were going to eat them they do not need mineral water. (pretty sure this is a wind up) (horror)
Cheers. I do have some wild flowers at the back of the garden, to be honest I'm kind of running out of room now. The Sunflowers have yet to flower, but I recall the bee's went nuts for them last year. I also only use organic methods within the garden, no slug pellets, fertilizers or sprays. I even water the plants with mineral water (bit extreme I know) :)
P.s. Well done for giving a reasonable amount, lots of interesting and useful stuff. :) This is also well worth a look while you wait for your pack. https://friendsoftheearth.uk/bees/bee-cause-what-you-can-do