A large swimming pool can hold a million gallons of water.
A million gallons of water -- How much is it?
If you start browsing through our water-use topics you'll see that water-use data are usually expressed in million of gallons of water used per day (Mgal/d). You can use a swimming pool to visualize how much a million gallons is.
If you were a swimming-pool builder and a customer asked you to build a pool that would hold a million-gallons, then they had better have a big yard! You would need to build a pool about 267 feet long (almost as long as a football field), 50 feet wide, and 10 feet deep. The cube on the right side shows you that 1 million gallons would form a cube that is 51.1 feet on each side.