What Is the Nominal Flow Rate of Pool Pumps?

It is important to install a swimming-pool pump of the correct power and capacity. A pool pump circulates the pool's water through a filter, cleaning it and removing impurities.

  1. Minimum Flow Rate

    • Minimum flow rate is determined by the size of the pool in gallons, and the time required to move the entire volume through the filter once or twice. A typical turnover rate is between 8 and 10 hours. An 18,000 gallon pool, with a turnover rate of eight hours, requires a pump with a minimum flow rate of 38 gallons per minute.

    Maximum Flow Rate

    • Maximum flow rate is determined by the size of the pipes used in your filter system. A 2-inch pipe has a flow rate of 73 gpm. A 1 1/2-inch pipe has a flow rate of 42 gpm. Use the lowest number to determine your maximum flow rate.

    Nominal Flow Rate

    • Use the maximum and minimum flow rates to determine your nominal flow rate. Calculate your ideal range. The flow rate on the low end of the range is your optimum setting.