Our cats have 6 fully understood the operation and accepted the fountain, a relief, the water is perfectly clean. A flat noise (we have placed in the hangar so no worries for us but it may bother apartment, even if the water is very nice to hear the sound flow produced by the device itself is audible) . Second downside, our dog did not accept food or running water, or water from the bowl. Complete blockage (fear of noise-it seems) to do with the time (in test for 3 weeks) but it does not seem inclined to approach it.