Fountains are not a maintenance-free garden feature. Most of them use a small pump to recirculate water from the basin back up to the top of the fountain where it will allow gravity to pull it back down again. For best results, use distilled water in your fountain and keep enough water in it that the pump is submerged at all times. Thanks to evaporation and creature drinking out of the fountain, the water can drop below optimum, so plans to refill it must be made. If you live in an area where mosquitos are a problem, you might also want to filter the water as it circulates. Finally, you should periodically empty your fountain and clean it. This will help protect the pump and maintain cleanliness for anything drinking from it.