How Long To Run Pool Pump Explained

How Long To Run Pool Pump Explained

If you are a new pool owner and find yourself setting up the system for the first time, you’re probably wondering how long to run pool pump. The answer to the question is not as simple as you might think. Many pool companies in the past have tried to standardize this by saying “run the pump for 8-12 hours”. Doing that will likely run the pool ‘enough’, but there’s a science to how long to run the pool pump.

Step 1: Calculate Total Gallonage  

First, you should know how large your pool is and what is the total gallons of the pool. You can find this out with some simple math. If you have a rectangular pool it’s easy. Do a length multiplied by width equals surface area calculation. If you have a free form pool, you’ll need to take multiple lengths and multiple widths to find the average of each. 

Once you have the surface area, take an average of three depths in the pool, shallow middle and deep end, then multiply that average by the surface area. This gives you the cubic feet of water in the pool. Multiply the cubic feet of water by 7.48 to give you the gallons in the pool.  

Step 2: Find Your Pool’s Gallons Per Minutes

Next, you need to know the gallons per minute your pump is putting out. This can be found by installing a flowmeter on your return line.  You can also estimate the gallons per minute by looking up the pump curve for your swimming pool pump. Find the pump manufacturer and model number on the side of the pump, and then look for the pump curve in the manufacturer’s website. It’ll look something like this.  Total dynamic head is on one axis, and the gallons per minute is on another axis of the pump curve. A good explanation of how to read a pump curve can be found here.

How Long To Run Pool Pump Calculation

Once you know the volume of your pool and you know roughly the gallons per minute of your pump, you can now estimate how long it takes to turn over your total gallons. Say your pool is 15,000 gallons and your pump is 95 gallons per minute. 15,000/95 = 158 minutes or 2 hours 38 minutes. This means if you want to turn your pool over twice every day you only need to run your pump for a little over 5 hours a day.  

How Long To Run Pool Pump Explained Poolside

How Long To Run Pool Pump With Variable Speed Pump

Now, if you have a variable speed pump, you’ll want to think about this a bit differently.  You can see how you might want to reduce the speed of the pump to a lower gpm so you can run the pump longer and at a lower speed.  Often a variable speed pump will be setup to run 24 hours a day.  This prevents the pool from ever sitting stagnant. It also allows for constant skimming action pulling debris off the surface of the pool. Even better, it can do that all for the same or less per month in electrical use.

How Long To Run Pool Pump With Single Speed Pump

If you have a standard single speed pool pump, you might want to look into the incentives being offered by your electric company or your state for swapping out your pool pump for a variable speed pump. Check the energy star website for any rebates in your area. The cost of a variable speed pool pump will often pay for itself over time. However, it’s never a bad idea to check for rebates. The same can be said about a 2 speed pool pump, too. Variable speed pool pumps are more advanced.


As you can see how long to run pool pump can vary depending on your pool and your pool pump selection. In the end like many things in life, it depends.