gosh I know how annoying that is. As soon as you fill it up, they knock it over and spill it and after many times you get the feeling they're doing it deliberately to mess with your mind!
Get a heavy square bowl, one that is very hard to knock over. if it is on tiles, you can also use glue-tak under the bowl to stop it moving.
Good luck.. and yes they do get enjoyment out of spilling the water and seeing you frustrated, they have nothing better to do lol
Just wait til it gets older and fussier and sticks its nose in the air at every meal you offer it!