These are typically small children's pools, either pre-formed out of plastic or inflatable. No filtration system is involved, so the water needs to be changed daily.
Some splasher pools use molded PVC poles to form a structure that holds a heavy vinyl liner or bladder, which in turn holds the water. Another popular version uses a heavy vinyl liner and an attached, inflatable top ring. This pool is strong enough to form and hold its own round structure and can be as large as 22 feet round. The oval style utilizes side struts to brace the water weight of up to 22,000 gallons in a 17 foot by 50 foot pool.
Steel walls and vinyl liners comprise these backyard structures. They are year round pools with a complete filtration system and need winterization in cold climates. Most are uniformly 4 feet deep, but some can include a deep end up to a 7 1/2 feet, along with decking and fencing.
These pools vary from smaller freestanding types to in-ground structures up to 50 feet long. They are narrow but not deep and may offer resistance to swim against in the form of a current, while others mimic larger lane or competition pools.
This large category includes concrete pools that are poured, then painted with either epoxy or chlorinated rubber-based paints. Shotcrete or gunite pools feature reinforced concrete sprayed under pressure against a matrix of wire lathe lining the desired excavated shape. Others have pre-fabricated walls that bolt together to form the desired shape. A track called coping holds a beaded vinyl liner in place to complete that installation. These pools can be free-form, kidney shaped or any geometric form desired. Fiberglass pools are pre-formed and delivered by truck and may need to be hoisted into a backyard via a large crane. Fiberglass offers the smoothest surface which deters algae from forming.
Very expensive negative edge or infinity pools provide the illusion of water reaching to the horizon with no visible top barrier on one end. Perimeter overflow pools have a channel built around the perimeter that catches and recycles the water that appears to flow over the edges of the pool. Ocean pools built for homes at the edge of the seashore use ocean water to create a natural, safe swimming environment without using chemicals or worrying about contact with marine life. Ocean water is pumped in and out of the swimming area which can be as large as the homeowners desire.
Olympic-size pools are indoor heated pools designed to meet standards for lighting, size and composition and must have painted lane markers, floating lane markers and the ability to register and display electronic competitive race results. Wave pools in water parks generate waves giving users the illusion of being in moving ocean water. Some of these pools have a zero-entry feature, which is a gradual sloping entry side that permits children, elderly users or people with accessibility problems to enter the water area without stairs or steps.