When I caught her, it was in our bathroom downstairs. I fussed and put the lid down.
I thought she had quit drinking out of the toilet, but noticed her water bowl was never empty. I checked in the upstairs bathroom, nobody uses, and sure enough, the toilet had about 2 inches of water in it.
Now I go up there and kept it full for her. I have to be very careful when I clean it and flush several times. She gets very upset with me.