What do you do if your toddler doesn't want to drink water?

You can make juice for him. Make smoothie or fruit slush for him. Also wit kids when we make it a point that hey should do a particular thing, they simply do not want to that thing. So I suggest do not show your kid what you want out of him and he will drink water without any effort being put. Make him run around, play with him. When he will get tired he will himself ask for water. Try getting a new water bottle for him. Perhaps of his choice. Carry bottle to the park. Seeing other kids having a water break your kid too will want go have it.