A swimming pool is an artificial pool for recreational bathing, sometimes used for exercise and relaxation. It may be heated or unheated, and it usually contains chlorinated or salt water. It can be surrounded by a deck and equipped with a diving board, a slide, a diving pit, or other facilities. It may also contain other features such as fountains, splash pads, wave machines, varying depths of water, islands, bridges, and underwater lighting. Private pools are often located in backyards, and they may be built from brick, stone, or fiberglass. Public pools are typically larger than private ones, and they may be located in parks or public buildings such as natatoriums.
In the United States, there are an estimated 10.6 million residential and 309,000 public swimming pools. Swimming is a popular sport, but many adults and children are unable to swim or lack basic swimming skills. Swimming pools can pose a risk of drowning, and their deepest areas should be at least 2.4 m (7 ft 10 in) to reduce this danger. Many municipalities require the use of lifeguards and other safety precautions at public pools, and many homeowners install residential pool fences to ensure the safety of children and pets who visit a pool.
A deck can be made of a variety of materials, and it is important that the surface is skid-resistant and can be easily cleaned. Tiled surfaces are common, and they can coordinate with interior design schemes or blend into a natural environment. Other options include poured-in-place concrete and precast slabs. If a pool deck is made of wood, it should be treated with chemicals to protect it from mold and mildew.