How many gallons per minute (GPM) can 500 feet of 4-inch supply line flow when not being pumped?

The flow rate for a 4-inch supply line is determined by various factors including the diameter of the pipe, the length of the section being considered, and the pressure within the line. For a standard 4-inch supply line under typical conditions (without being actively pumped), the expected flow rate is around 800 gallons per minute. This figure is a general guideline often used in firefighting and water supply contexts, where flow calculations are critical for ensuring adequate water delivery during operations.

In this case, since the answer indicates 800 GPM, it aligns properly with established flow rate tables for a 4-inch pipe under the specified conditions. The other answers suggest much higher flow rates that exceed typical capabilities of a 4-inch line without pumping assistance, which would be unlikely in practical applications. Thus, the choice of 800 GPM is the most accurate reflection of the potential flow rate for a 4-inch supply line of 500 feet in length when not being actively pumped.