Buying a swimming pool pump motor for the first time can feel intimidating. Aside from having to deal with technical terms and calculations, you’ll have to go through several options. Where do you even start? Learning a few key basics puts you in control and helps you choose a motor that matches your pool’s size and circulation needs without overspending.
Know your flow rate
The flow rate tells you how much water your pump moves each minute. To calculate it, check your pool’s turnover rate, which measures how long it takes to circulate the full volume of water.
Most residential pools need one to two full turnovers per day. A common target is one complete turnover every five hours. This supports proper filtration while keeping your energy use in check.
Identify your pool’s capacity
Calculate your required flow rate in gallons per minute (GPM) using this formula:
(Pool volume in gallons ÷ turnover time in hours) ÷ 60 = required GPM
Example:
For a 20,000-gallon pool with a five-hour turnover:
20,000 ÷ 5 = 4,000 gallons per hour
4,000 ÷ 60 = 66.6 GPM
In this case, a swimming pool pump motor rated around 67 GPM would meet your needs.
Calculate the total head pressure
Total head refers to the overall resistance in your pool’s plumbing system. It accounts for pipe length, fittings, elevation changes, and any equipment the water flows through. It can be complex to calculate accurately, but don’t worry — you really only need a solid estimate to select the right pump.
To estimate head pressure, start by measuring the total length of piping between the pump and the return line. If your system includes a filter, you can assume the effective resistance is about half that length.
You may need to add two to twelve feet of head for additional equipment like haters or chlorinators. Also, add one foot of head for every foot your return line sits below the water surface.
Use your filter as your guide
Your swimming pool pump motor and filter must always work together. Never choose a pump with a higher flow rate than your filter can handle. Matching inlet and outlet pipe sizes also helps maintain smooth circulation — two-inch connections on both units typically work best when paired.
Find what you need right here
It’s easier to choose the right swimming pool pump motor here at All Pool Filters 4 Less! We offer a wide selection of swimming pool pump motors to suit different pool sizes and system layouts. Need help? Email
