There is one kind of between Electric Umbrella and Mouse Gears on the fountain side.
You have to listen very hard to hear it sometimes.
I'm sure someone will have a picture or better location description.
I always get a drink from it.
If you walk towards the Imagination pavilion, right after you walk through Innovations, there are rest rooms on your left. The water fountains are to the left of the restrooms. One fountain is a regular one, the other talks when you press the button.