It depends on what you want from a pool. The best value (dollars per gallon) will be the largest round pool that you can fit. An 18’ round pool holds around 8,000 gallons. A 24’ round and a 15’x30’ oval both hold around 15,000. The 24’ round is generally only a few hundred dollars more than the 18’ round, but it’s twice as big! The 15’x30’ oval is $1500 more than the 24’ round, and it has essentially the same amount of space and water.
That’s because oval pools have an entire apparatus – angular buttresses, hold down plates, underground straps, and stabilizing plates – that keep the pool from turning onto a round pool from the water pressure.
On a poorly-made (cheap) pool, the round pool will conceivably be stronger than the oval version. The price difference will probably be closer, too. That’s because the oval pool’s support structure won’t be as strong. On a well-made (more expensive) pool, the round and oval pools will be equally strong – and you’ll pay almost $2500 extra in materials, engineering, and installation to make the oval as strong as the round.
Price isn’t everything, though. You may decide on a pool shape for space, layout, landscaping or your planned usage.
An oval pool, especially with a nice deck, can look much like an inground pool – at a vastly lower price. It gives you more length for swimming laps. Depending on your back yard, it may fit better – though it will take up more ground area than the equivalent round. Some oval pools are available in a special “buttressless” model that uses heavier underground structure to allow almost no ground area to be taken up by struts. Expect this type of construction to cost $200 – $800 extra.
A round pool fits the use that most people give to a pool; playing, talking, floating on one of those chaises with a drink in the arm, and a little swimming. You don’t have to swim across a 24’ round; you can also swim in a circle that can go on forever!!
To a large extent, round pools also have more practical space for most activities. Sometimes an activity taking place across the narrow width of an oval pool can block access from one side to the other. Round pools have no corners to block off.