That's it, she sticks her foot in it. Lucky you. I've seen retrievers that lay down right on top of the dish or tip it over and try to swim in it. Some dogs just love to be in the water. Unless she tips it over I wouldn't worry about getting her fresh water every time she does it because that would be a pain. I don't know much for advice on how to stop this but perhaps getting a small automatic waterer for like a cat so she can't really fit her foot in but when she drinks it keeps coming out so she that has enough water. Some have an attachment for a two liter water bottle so it should hold enough for her.