How Long Will It Take to Fill up a Swimming Pool?

The Washington State University Extension assumes a flow rate of 18 gallons per minute from a 3/4-inch hose measuring 100 feet.

To determine how many gallons the hose pumps per hour, multiply the gallons per minute by 60 minutes. Eighteen gallons per minute equal 1,080 gallons per hour.

To determine how many hours it takes to fill a pool, divide the number of gallons the pool holds by the gallons per hour. At 1,080 gallons per hour, a pool holding 5,000 gallons takes 4.63 hours to fill.