A good size for a lap pool is anywhere from 45 to 75 feet in length, 6 to 8 feet wide and a minimum of 3 1/2 feet deep. While nearly any pool can be used to swim laps, a lap pool is perfect for those who want to use it primarily for exercise.
When it comes to the right length for a lap pool, the longer it is the less a swimmer will have to reverse direction. Most pools in the U.S. that are used for competitive swimming are 25 yards, or 75 feet, long. This length may be too great to fit in most back yards. A minimum of 45 feet, or 15 yards, is a good starting point for a lap pool. If there is more space, one can always extend it.
When thinking about the width of the pool, one should consider how many people will be swimming at one time. If the lap pool is for only one person, then a width of 6 to 8 feet is good. Add on 4 feet for each additional swimmer.
Since a lap pool's primary use is for exercise and swimming laps, it does not have to be too deep. A lap pool should be just deep enough so that the swimmer's arms and legs do not bump the bottom, and 3 1/2 feet should leave plenty of room.