Pools can be either indoors or outdoors. They can be of any size and shape, and inground or above ground. Most pools are permanent fixtures, while others are temporary, collapsible structures.
Private pools Private pools are usually smaller than public pools. Home pools can be permanently built-in, or be assembled above ground and disassembled after summer. Privately owned outdoor pools in backyards or gardens started to proliferate in the 1950s in regions with warm summer climates, particularly in the United States with
desegregation. A
plunge pool is a smaller, permanently installed swimming pool. Construction methods for private pools vary greatly. The main types of in-ground pools are gunite
shotcrete, concrete,
vinyl-lined, and one-piece fiberglass shells. Many countries now have strict
pool fencing requirements for private swimming pools, which require pool areas to be isolated so that unauthorized children younger than six years cannot enter. Many countries require a similar level of protection for the children residing in or visiting the house, although many pool owners prefer the visual aspect of the pool in close proximity to their living areas, and will not provide this level of protection. There is no consensus between states or countries on the requirements to fence private swimming pools, and in many places they are not required at all, particularly in rural settings.
Children's pools Inexpensive temporary
polyvinyl chloride pools can be bought in supermarkets and taken down after summer. They are used mostly outdoors in yards, are typically shallow, and often their sides are inflated with air to stay rigid. When finished, the water and air can be let out and this type of pool can be folded up for convenient storage. They are regarded in the swimming pool industry as "splasher" pools intended for cooling off and amusing toddlers and children, not for swimming, hence the alternate name of "kiddie" pools.
Toys are available for children and other people to play with in pool water. They are often blown up with air so they are soft but still reasonably rugged, and can float in water. File:Black Labrador Retriever kiddie pool..jpg|A black
Labrador Retriever bathing in a kiddie pool File:Kids.jpg|Children playing in an inflatable pool
Public pools , in South London Public pools are often part of a larger
leisure center or recreational complex. These centres often have more than one pool, such as an indoor heated pool, an outdoor (
chlorinated,
saltwater or
ozonated) pool which may be heated or unheated, a shallower children's pool, and a paddling pool for toddlers and infants. There may also be a
sauna and one or more
hot tubs or
spa pools ("
jacuzzis"). Many upscale hotels and holiday resorts have a swimming pool for use by their guests. If a pool is in a separate building, the building may be called a
natatorium. The building may sometimes also have facilities for related activities, such as a diving tank. Larger pools sometimes have a
diving board affixed at one edge above the water. Many public swimming pools are
rectangles 25 m or 50 m long, but they can be any size and shape. There are also elaborate pools with
artificial waterfalls, fountains,
splash pads, wave machines, varying depths of water, bridges, and island bars. Some swimming facilities have
lockers for clothing and other belongings. The lockers can require a coin to be inserted in a slot, either as deposit or payment. There are usually showers – sometimes mandatory – before and/or after swimming. There are often also lifeguards to ensure the safety of users. Wading or paddling pools are shallow bodies of water intended for use by small children, usually in parks. Concrete wading pools come in many shapes, traditionally rectangle, square or circle. Some are filled and drained daily due to lack of a filter system. Staff chlorinate the water to ensure health and safety standards.
Competition pools :
See: #Dimensions (above) and Swimming (sport)#Competition pools long course swimming pool standard, used at the World Championships and
Summer Olympics World Aquatics sets standards for competition pools: long and at least deep. Competition pools are generally indoors and heated to enable their use all year round, and to more easily comply with the regulations regarding temperature, lighting, and automatic officiating equipment. An
Olympic-size swimming pool (first used at the
1924 Olympics) is a pool that meets FINA's additional standards for the Olympic Games and for world championship events. It must be wide, divided into eight lanes of each, plus two areas of at each side of the pool. Depth must be at least . The water must be kept at and the lighting level at or greater than 1500
lux. There are also regulations for color of lane rope, positioning of
backstroke flags (5 metres from each wall), and so on. Some design considerations allow the reduction of swimming
resistance making the pool faster: namely, proper pool depth, elimination of currents, increased lane width, energy absorbing racing lane lines and gutters, and the use of other innovative hydraulic, acoustic and illumination designs.
Exercise pools In the last two decades, a new style of pool has gained popularity. These consist of a small vessel (usually about 2.5 × 5 m) in which the swimmer swims in place, either against the push of an artificially generated water current or against the pull of restraining devices. These pools have several names, such as
swim spas,
swimming machines, or
swim systems. They are all examples of different modes of
resistance swimming.
Hot tubs and spa pools Hot tubs and spa pools are common heated pools used for relaxation and sometimes for therapy. Commercial spas are common in the swimming pool area or sauna area of a
health club or fitness center, in men's clubs, women's clubs, motels and exclusive five-star hotel suites. Spa clubs may have very large pools, some segmented into increasing temperatures. In Japan, men's clubs with many spas of different size and temperature are common. Commercial spas are generally made of concrete, with a
mosaic tiled interior. In the early 2000s, with the innovation of the pre-form composite method where mosaic tiles are bonded to the shell this enables commercial spas to be completely factory manufactured to specification and delivered in one piece. Hot tubs are typically made somewhat like a
wine barrel with straight sides, from wood such as
Californian redwood held in place by metal hoops. Immersion of the head is not recommended in spas or hot tubs due to a potential risk of underwater entrapment from the pump suction forces. However, commercial installations in many countries must comply with various safety standards which reduce this risk considerably. Home spas are a worldwide retail item in western countries since the 1980s, and are sold in dedicated spa stores, pool shops,
department stores, the Internet, and catalog sales books. They are almost always made from heat-extruded
acrylic sheet
Perspex, often colored in
marble look-alike patterns. They rarely exceed and are typically deep, restricted by the availability of the raw sheet sizes (typically manufactured in Japan). There is often a mid-depth seating or lounging system, and contoured lounger style reclining seats are common. Upmarket spas often include a drinks tray, lights,
LCD flat-screen TV sets and other features that make the pool a recreation center. Due to their family-oriented nature, home spas are normally operated from . Many pools are incorporated in a
redwood or simulated wood surround, and are termed "portable" as they may be placed on a
patio rather than sunken into a permanent location. Some portable spas are shallow and narrow enough to fit sideways through a standard door and be used inside a room. Low power electric immersion heaters are common with home spas. Whirlpool tubs first became popular in the U.S. during the 1960s and 1970s. A spa is also called a "jacuzzi" there, as the word became a generic after-plumbing component manufacturer;
Jacuzzi introduced the "spa whirlpool" in 1968. Air bubbles may be introduced into the
nozzles via an air-bleed
venturi pump that combines cooler air with the incoming heated water to cool the pool if the temperature rises uncomfortably high. Some spas have a constant stream of bubbles fed via the seating area of the pool, or a footwell area. This is more common as a temperature control device where the heated water comes from a natural (uncontrolled heat)
geothermal source, rather than artificially heated. Water temperature is usually very warm to hot – – so bathers usually stay in for only 20 to 30 minutes.
Bromine or
mineral sanitizers are often recommended as sanitizers for spas because
chlorine dissipates at a high temperature, thereby heightening its strong chemical smell.
Ozone is an effective bactericide and is commonly included in the circulation system with cartridge filtration, but not with sand media filtration due to clogging problems with turbid body fats.
Ocean pools in Sydney, Australia In the early 20th century, especially in Australia,
ocean pools were built, typically on headlands by enclosing part of the rock shelf, with water circulated through the pools by flooding from tidal tanks or by regular flooding over the side of the pools at high tide. This continued a pre-European tradition of bathing in rockpools with many of the current sites being expanded from sites used by
Aboriginal Australians or early European settlers. Bathing in these pools provided security against both rough surf and sea life. There were often separate pools for women and men, or the pool was open to the sexes at different times with a break for bathers to climb in without fear of observation by the other sex. These were the forerunners of modern "Olympic" pools. A variation was the later development of sea- or harbour-side pools that circulated sea water using pumps. A pool of this type was the training ground for Australian Olympian
Dawn Fraser. There are currently about 100 ocean baths in
New South Wales, which can range from small pools roughly 25 metres long and "Olympic Sized" (50m) to the very large, such as the 50 × 100 m baths in
Newcastle. While most are free, a number charge fees, such as the
Bondi Icebergs Club pool at
Bondi Beach. Despite the development of chlorinated and heated pools, ocean baths remain a popular form of recreation in New South Wales. A semi-natural ocean pool exists on the central coast of New South Wales; it is called The
Bogey Hole.
Infinity pools An
infinity pool (also named
negative edge or
vanishing edge pool) is a swimming pool which produces a visual effect of water extending to the horizon, vanishing, or extending to "infinity". Often, the water appears, from the perspective of the swimmer, to fall into an ocean, lake, bay, or other similar body of water. The illusion is most effective whenever there is a significant change in elevation (e.g., a roof-top swimming pool with a lake or ocean view), though having a natural body of water on the horizon is not a limiting factor.
Natural swimming pools and ponds Natural swimming pools were developed in central and western Europe in the early and mid-1980s by designers and
landscape architects with
environmental concerns. They have recently been growing in popularity as an alternative to traditional swimming pools. Natural swimming pools are constructed bodies of water in which no chemicals or devices that disinfect or
sterilize water are used, and all the cleaning of the pool is achieved purely with the motion of the water through biological filters and plants rooted
hydroponically in the system. In essence, natural swimming pools seek to recreate swimming holes and swimmable lakes, the environment where people feel safe swimming in a non-polluted, healthy, and
ecologically balanced body of water. Water in natural pools has many desirable characteristics. For example, red eyes, dried-out skin and hair, and bleached
swimsuits associated with overly
chlorinated water are naturally absent in natural pools. Natural swimming pools, by requiring a
water garden to be a part of the system, offer different aesthetic options and can support amphibious wildlife such as snails, frogs, and salamanders, and even small fish if desired.
Zero-entry swimming pools aquatic park in
Naperville, Illinois, United States A
zero-entry swimming pool, also called a
beach entry swimming pool, has an edge or entry that gradually slopes from the deck into the water, becoming deeper with each step, in the manner of a natural beach. As there are no stairs or ladders to navigate, this type of entry assists older people, young children and people with
accessibility problems (e.g., people with a physical disability) where gradual entry is useful.
ADA requirements Beginning in 2012, standards for accessible design were put into effect by the
Americans with Disabilities Act that require at least two modes of accessible entry in large sized swimming pools. A zero-entry swimming pool is in accordance with the standards. They also create equality of access to a physical activity with multiple benefits. Research suggests that swimming can be therapeutic and induces healthier physical and mental states.
Indoor pools Once known as "natatoriums", indoor pools are located inside a building with a roof and are insulated by at least three walls. Built for year-round swimming or training, they are found in all climate types. Since the buildings around indoor pools are insulated, heat escapes much less, making it less expensive to heat indoor pools than outdoor pools (all of whose heat escapes). Architecturally, an indoor pool may look like the rest of the building, but extra heating and ventilation and other
engineering solutions are required to ensure comfortable humidity levels. In addition to drainage and automatic pool covers, there are a number of ways to remove the humidity present in the air in any wet indoor environment. Efficient
dehumidification in the indoor pool environment prevents structural damage, lowers energy costs for cooling or heating, and improves the indoor climate to provide a comfortable swimming environment. Some colleges, universities, and high schools have buildings that use the term "natatorium" in their names, especially when the building houses more than just a swimming pool, for example a
diving well or facilities for
water polo. The word
natatorium was borrowed from
Late Latin "place for swimming" into English in New England in 1890.
Suspended swimming pool This type of swimming pool is suspended high above the ground. A prominent example is the
Sky Pool in London's
Embassy Gardens, the world's first floating pool.
Cruise ships Cruise ships often have swimming pools, water slides and other water features. The pools use filtered and chlorinated sea water. The
Titanic had a saltwater swimming pool. == Other uses ==