I've had this cat water fountain running on the kitchen floor now for about 3 weeks. She started drinking from it after the first week.
Noise level: The only thing I hear is the water making gurgling noises, which doesn't bother me. On a couple of occasions, I heard some vibration, but I just wiggled the water reservoir on the back of the unit and it quit making noises.
I don't have to refill it during the week. I just clean it and refill it every Saturday morning. So far, the only cleaning I've had to do is just wipe the surfaces.
