How to get 6 and a half month old to drink more water?

[Stevie]

Ive read that formula fed babies should drink more water (cooled boiled water of course) i make DD a bottle of water everyday and try a few times a day to get her drink it, she sucks once or twice realises its nto milk spits it out and then clamps her mouth shut, ive tried sippa cups too but she doesnt seem to like it.
I got her a tommy tippee sippa cup today (the ones with the silicone mouth peice) which i will use in the next few days (im working tomorrow so might not get a chance to) but she seems to hate water,
is there something im doing wrong? i know your probably gonna say "she doesnt need it" and i know that but now with her eating more solids and ESP now that she's getting around more and using more energy id LOVE it if i could find a way to get more water into her.
TIA ladies xx