I had the same problem. There isn't a bowl they can't tip if they're determined enough, it does not exist, unless you give them a bucket or a fountain/dispenser sort of thing. I didn't want to do that because they're always plastic.
So I came here and asked the same question. Someone, I forget who, but they're a genius, told me to velcro the bowl down. I did, and she can't tip it over anymore. I velcro'd it to the placemat I have, but you could velcro it to the floor too. The only problem is that after the velcro gets wet a few times sometimes it comes off, but it costs, what 50 cents to replace, and after a few weeks the cat stops doing it anyway.
I have heard a few theories on why they do this, from trying to bury it, to playing in it, to that they don't like their whiskers touching the sides.
Mine started doing it out of nowhere when she was about 6 mos. My sister's cat likes to drag his bowl across the floor, which may be where she got it from except my bowls had no-slips. Anyway, if you have something she can drag, like a big, heavy coffeemug, try that first, and then if she keeps tipping it, velcro it down.
Mine would tap it around until it was almost empty, dump the whole thing over onto the floor, watch me clean it up and refill it, and do it again. And again. I ended up giving her about an inch of water in a big bowl until I could figure out what to do.