Thankfully our cats aren't particular about only drinking from running water. We just keep stainless steel bowls full of water throughout the house for them. I suppose one thing that would concern me about these fountains is how easy/difficult they are to keep clean. Does anyone know if they have a tendency to develop mold inside the internal parts? I had a few decorative water fountains as well as a decorative humidifier (it would create a glowing bowl of fog), and both of these were a pain to clean. The nozzles would get clogged up with what I'm assuming were calcium or hard water deposits, and the water container was regularly developing a residue along the walls of it.