Figure 5-1 RIVUXG Earth’s Water Amount in Comparison If you were to collect all of Earth’s water, it would be a ball about 860 mi in diameter. If you were to burst this imaginary ball of water, the resulting flow would cover the contiguous United States (lower 48 states) to a depth of about 107 mi. This is similar to how much water is suspected to be hiding on Mars and Saturn’s moon Enceladus and far less than exists beneath the surfaces of Jupiter’s moon Europa or Saturn’s moon Titan.