Zoee never tipped her water bowl. But I think they make bowls that are "supposedly" tip proof.
Here are some links I found:
http://www.amazon.com/No-Tip-Mirror-Finish-Poodle-Cocker/dp/B0007ST8Y4/ref=sr_1_8?ie=UTF8&s=home-garden&qid=1202665326&sr=1-8 ]mirror finish[/URL]
Stainless Steel
They are basically the same dish, but I guess the idea is the bottom needs to be larger than the top. But I'm sure water can still be splashed out, it just might be a bit more difficult to actually turn over the whole dish.