Q:

# How many gallons of water does the average 21-foot swimming pool hold?

A:

The average 21-foot round pool with a depth of 48 inches holds 13,500 gallons of water. A 21-foot round pool with a depth of 52 inches holds 14,500 gallons, according to Robelle.

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Measuring all dimensions in feet, the formula to calculate water capacity for round or oval pools is: average depth x length x width x 5.9. The formula for a square or rectangular pool is: average depth x length x width x 7.5. Accurately calculating water capacity allows owners to determine the correct amount and type of chemicals necessary to clean the pool and maintain the water's pH balance.

## Related Questions

• A:

A 15 x 30-foot oval pool with an average depth of 48 inches holds 12,000 gallons of water. A pool with the same exterior dimensions and an average depth of 52 inches holds 14,800 gallons of water.

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• A:

A 24-foot-round, 52-inch-deep pool holds a rounded 14,715 gallons of water if it is filled to the brim, or about 13,594 gallons if it is filled to an average depth of 48 inches. Most pools are not filled to the brim.

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• A:

The amount of gallons of water in a pool varies greatly depending on the size of the pool. The average in-ground backyard pool holds between 18,000 and 20,000 gallons of water.