Flow Rate

Also Known As: Rate of Flow

The pool pump circulates the water through the filtration and chemical cleaning system. A proper flow rate pulls all of the water through the system within a particular period of time. The right sized pump will deliver the flow rate that is needed for a particular pool.

If a pump is too large, the energy costs can climb. If a pump is too small, the water may not be filtered properly.

Flow rate depends on the size of the pool and the turnover rate — or the desired rate that the pool’s water is circulated. An online calculator can find the flow rate, or it can be calculated by hand very easily. First, find the capacity of the pool (length x width x average depth), by multiplying the volume of the pool (in feet) by 7.5 (the number of gallons in a cubic foot). The result is the number of gallons of water that the pool can hold. Divide this value by the desired turnover rate — 6 hours, 8 hours or 10 hours. Finally, divide the answer by 60 to find the minimum flow rate per minute. Use a chart to find a pump that matches the flow rate of the pool.

A flow meter will show the flow rate of the pump at any given time. If the pump is the proper size, a flow rate that is either too low or too high could indicate a problem with the pump or filtering system.