Unlike other reviewers, my cats loved this fountain. I have three, and the fountain did a good job. I only put filtered water into the unit, and I cleaned it weekly.However, this week, my catsitter noticed that the motor had stopped. She unplugged the unit. I came home and thought it might just need cleaning. I discovered that the motor housing had melted. The spinning plastic bit of the motor had fused to the unit.Thank goodness my cat sitter unplugged it. I can't imagine what might have happened if she hadn't.Of course, anyone that has used a fountain knows that once your pets get used to it, they won't drink water any other way. Luckily Petsmart had a stainless steel 360 available. It is a similar motor but smaller. I've used the plastic ones previously. Anyways, I won't go back to the big dog unit after seeing what happened with the motor housing.