The standards for pools considered acceptable for competition are defined by the Fédération Internationale de Natation (International Swimming Federation), also known as FINA. While it's not often that a pool meets every guideline, several aspects usually remain consistent at a quality lap swimming or competitive swimming facility. Although both metric and non-metric pool lengths are used in USA Swimming-sanctioned competitions, the only records FINA will recognize are for races that were swum in long course pools, in long course meters (LCM).
Competitive swimming pools are either built in short course or long course. Short course pools, which are more common at public swimming locations or high schools, are 25 meters (or 25 yards) long. Long course pools, which are usually found at higher-end swimming facilities or college campuses, are 50 meters long. Some long course pools are designed to be 50 meters long and 25 meters or yards wide so that they can be used for both short and long course competitions. With pools like this, a dividing structure called a bulkhead is used to set the pool up for short or long course.
Both short and long course pools are divided into lanes that are about eight feet wide. The number of lanes depends on the pool's width, but most pools have at least four lanes and can have as many as 10. Lane lines, which are wire cables covered with plastic buoys, separate each lane. The color of the plastic buoys changes at the 15-yard (or 15-meter) mark in a short course pool, or at the 25-meter mark in a long course pool. Sometimes, just one plastic buoy will change color to mark either distance as opposed to a total color change.
The pool will be at least 6.5 feet deep, usually deeper if a diving board is present. Water temperatures vary, but are typically somewhere between 77 and 82 degrees Fahrenheit.
On the bottom of the pool, there are lane markings, which are usually lines in different-colored tile that end in a T shape. The T is centered on the end of each wall at a distance of 5.25 feet from the wall itself. On the wall, there is a + sign marking that's half a meter long and one foot below the surface of the water. Both of these markings are meant to help swimmers properly execute their turns. Many pools with a shallow and deep end will also have a line running across the lanes width-wise that marks the beginning of the depth change.
Almost every individual swim or relay leg begins with a dive from the starting blocks. The starting block platform, which is covered in some form of non-slip material, is usually between 1.5 and 2.5 feet above the surface of the water. The block itself, which is square, is typically half a meter wide by half a meter long. Some newer starting blocks have an adjustable foot rest that swimmers can use to propel themselves farther off the block.
Backstroke races are the only races that don't begin from the block, and instead begin in the water with the swimmer holding onto either the pool gutter or the handles, grips or slots that extend from the starting block. The backstroke grips are positioned parallel to the surface of the end wall, between 1 and 2 feet above the surface of the water.
Nearly all pools include flags for backstroke races, which are used by swimmers to get a sense of how far they are from the wall. The flags, per FINA requirements, must be at a height between six and eight feet above the surface of the water, and are always located five meters or yards from the wall. If a diving event is taking place - meaning if a diving board is being used - the flags are temporarily removed. Diving boards are positioned at either six meters or 11 meters (approximately 20 feet or 36 feet, respectively) above the surface of the water and are also movable to accommodate swimming competitions.