Pool Guide/Care

What Size Pump Do I Need for My Pool?

Whether you’re buying a pump for the first time or looking for a replacement, it’s important to carefully evaluate your pool needs. This is mainly because today’s pumps are much more efficient and if you simply go by horsepower ratings, chances are you’ll oversize your pump. So, what size pump do I need for my pool?

In this article, we’ll discuss how to choose the right sized pump for your pool. We’ll point out everything from determining the minimum and maximum flow rates to checking the filter.

What Size Pump Do I Need for My Pool?
What Size Pump Do I Need for My Pool?

Determine the Minimum Flow Rate

Also referred to as the turnover time, this refers to the flow rate that must be maintained to circulate all the water in the pool through the filter within a certain number of hours. A home pool should have a turnover time of about eight to ten hours. If your pool is used heavily aim for a shorter turnover rate. Once you’ve determined a turnover rate, you can then calculate the precise needs of your pool using the following steps:

Determine the number of gallons your pool holds. There are plenty of pool gallon calculators you can use. For example, let’s assume that you have 24000 gallons of water in your pool.

Determine the number of gallons that need to be pumped per hour to clean all your pool’s water in 8 hours. Divide the amount of water in your pool (in gallons) (from the step above) by eight. So, if your pool has 24000 gallons of water, the equation would look as follows:

24000 ÷ 8 = 3,000

Since pumps are categorized by the gallons, they move every minute, you’ll need to divide the number above by 60. Determining the gallons per minute:

24,000 gallons ÷ 8 = 3,000 ÷ 60 = 50 GPM (gallons per minute)

Determine the Maximum Flow Rate

The flow rate of any given pool system is limited by the equipment and the size of the piping. This determines the maximum rate of flow through the system.

You’ll want to start by checking the pool system plumbing. Even if your pump can move 80 gallons per minute, that won’t make much of a difference if the piping only allows 50 GPM through it. An oversized pump will actually damage the piping as it will strain against the piping.

What Size Pump Do I Need for My Pool: Flow Rate
What Size Pump Do I Need for My Pool: Flow Rate

Check the Plumbing Flow Rate

Generally, the velocity of the water through the piping shouldn’t exceed 7 feet per second. Count the intake lines as that will determine what the maximum flow into the pump will be. It’s also important to make sure the lines going back into the pool will support the same level of flow.

Bottom Line

By following the steps mentioned above, you can now answer the question: what size pump do I need for my pool. It also helps to note that the GPM of your pump will directly relate to the filter’s GPM. You will want to reduce any additional strain on your pump motor by making sure the filter’s GPM is higher than your pump’s GPM. Contact your local professional for additional assistance or questions.