babies will feed more to keep them cooled down! they get some water within your milk x
No water until 6 months and then tap is fine x
No definitely not! No water for under 6 months. I guess they may have that guidance in place in case anyone went against guidance of waiting to 6+ months. Also might be in relation to using boiled water for other things like making formula etc. but not to give baby directly. They get enough water through milk so may just need some extra hydration that way.
I've been told not to introduce water until baby starts weaning. In hot weather they'll be more thirsty so will need more milk than usual