She may be annoyed that she hasn't found the water herself. She prefers wild water that must be hunted and captured, rather than the water provided for her in her bowl. As in, the water glass I have by my bed at night, the water on the shower floor, the water in the humidifier base, etc.

She's not trying to avoid dust and hair in the water by finding alternate sources, either: I have personally witnessed her drink water out of a humidifier base that I hadn't gotten round to emptying for a couple of days that was covered with a thin layer of dust and had a dead fly floating in it. Which was no longer floating in it after she finished.