How fast does it take to fill 12000 gallons of water?

The time it takes to fill 12,000 gallons of water depends on the flow rate of the water source. For example, if the flow rate is 10 gallons per minute, it would take 1,200 minutes, or 20 hours, to fill the tank. Conversely, if the flow rate is 100 gallons per minute, it would only take 120 minutes, or 2 hours. Thus, the filling time varies significantly based on the flow rate.