Even if it was standard chlorinated pool water, it's not going to hurt the koala. If it was drinking it every day, then yes, ... but a poolside sip is harmless.
This is an amazing show of curiosity and kindness between a girl and a Koala, she did a great job of creating trust within the Koala and for that she was rewarded with love! ❤ That's amazing! 🏆🏆🏆