Water is the best drink for thirst. Always have plenty of water available and show your toddler that you enjoy drinking it too.
Fruit juices (unsweetened) are good but expensive. One to two glasses a day is plenty. Toddlers should not have more than this. Fruit juice can be diluted with water. Avoid fruit juice drinks because they contain a lot of sugar.
link --> http://www.community.nsw.gov.au/documents/parfeed.pdf