We have two water bowls in different locations in the house. Each is filled with fresh water twice a day and thoroughly washed about twice a week. They are both stainless steel. Hannah is very picky about her water being fresh. If she feels it is not up to her standards, she will make it known that she needs fresh water by scratching on the toilet bowl. I think this is her way of saying...*I'd rather drink out of the toilet bowl than that water that has been sitting there all day.*