My Siamese cat (Charlie) has developed the habit of purposely knocking over his water bowl. I considered that it may not be fresh enough, we've since installed a water purifier and the problem has not discontinued. I really have no explanation as to why he would do such a thing, his food is near is water and is always undisturbed. I'm positive it's not because of the water freshness, there are times when he knocks over almost right after I've given a fresh bowl of purified water. He seems to be doing it more frequently now. Any suggestions on how to correct this problem will be greatly appreciated.