A traditional fountain is an arrangement where water issues from a source, fills a basin of some kind, and is drained away. Fountains may be wall fountains or free-standing. In fountains sheets of water may flow over varied surfaces of stone, concrete or metal. Basins may overflow from one into another, or the overflow may imitate a natural cascade. Many fountains are located in small, artificial ornamental ponds, basins and formal garden pools, and often they include sculpture.
In modern fountains the traditional gravitational pressure from an unseen reservoir at a higher level is not always practical. In many circumstances fountains obtain their water from a closed, recirculating system that must still be filled at the start from the local water supply system and also topped up through its life to offset the effects of evaporation. Allowance must also be made to handle overflow in the case of heavy rain.
The pressure that causes water to move through the fountain may be produced instead by a motor-driven (often submersible electric) pump. "Static head" is useful to quantify this pressure.
A water filter, typically a media filter, removes particles from the water -- this filter requires its own pump to force water through it and plumbing to remove the water from the pool to the filter and then back to the pool. The water may need chlorination or anti-algal treatment, or may use biological methods to filter and clean water.
The pumps, filter, electrical switch box and plumbing controls are often housed in a "plant room". Low-voltage lighting, typically 12 volt direct current, is used to minimise electrical hazards. Lighting is often submerged and must be suitably designed.
