Last Updated: December 6, 2020

How Long Should You Run a Pool Pump?

Written By: Pool Care Guide

Ideally, you want to run your pool pump 24 hours a day because the longer it runs the fewer problems you’ll have. That said, the recommendation will naturally change with the environmental factors, the capabilities of your pool pump and its filtration system, and the frequency, quality, and chemicals of your maintenance routine.

With those varying factors, it’s understandable why advice can vary from person to person. With that in mind, there are a couple of different methods for determining how many hours you should run your pool pump.

The General Recommendation - Gage-Bidwell’s Law of Dilution

The common recommendation is to follow the guidelines set forth by Gage-Bidwell’s Law of Dilution. 

In this rule, it says that if a pool’s water is circulated through its filtration system 3 to 4 times every day, its contaminated water will be diluted by roughly 95 to 98 percent. That means you should buy a pump that can filter your pool’s volume of water between 6 to 8 hours.

The time it takes all of your pool’s water to circulate through your pool pump is called its turnover rate. Now, we do understand that leaving the filter running 24 hours a day can lead to a very expensive electric bill. If you can’t afford to filter your water 24/7, you aren’t alone. 

Many people only filter their water once per day, and you can obviously do this too. However, if you do, you need to keep a closer eye on the health of your pool and likely increase the frequency of maintenance tasks such as scrubbing the pool walls and treating algae colonies.

The Economical Recommendation - Temperature-based Hours

Climates vary and seasons change. When temperatures and humidity rise, it typically gives increases the amount of debris and contaminants in the pool. If you use a pool pump with a 6 to 8-hour turnover rate, you can use the chart below to determine how long you should run your pool pump every day. We recommend finding the average monthly temperature for your local area and adjusting the pool pump’s hours per day accordingly.

Temperature Fahrenheit Temperature CelsiusHours Per Day
50-60°F10-15°C4 - 6 Hours Per Day
60-70°F15-21°C6 - 8 Hours Per Day
70-80°F21-27°C8 - 12 Hours Per Day
80-90°F27-32°C12 - 18 Hours Per Day

How to Calculate the Turnover Rate and Flow Rate

We know that a pool can quickly become toxic if the pool owner isn’t actively maintaining and filtering it. Algae grow, mosquitoes lay eggs, and diseases fester. The pool pump maintains your pool through circulation. It pulls water into it and pushes it out through its filtration system. The speed at which the pump pushes this water is called the flow rate and it is measured in Gallons Per Minute.

Here’s a table to quickly determine the turnover rate and the associated flow rate needed to achieve that turnover rate. If the pool volumes in this chart are not applicable to your pool, you can use the instructions below this table to calculate the turnover rate.

GPH = Gallons Per Hour, GPM = Gallons Per Minute

Pool Volume(Gallons)6-Hour Turnover Rate(Gallons / Hours)Flow Rate Needed for 6-Hour Turnover Rate(Turnover / 60 Minutes)8-Hour Turnover Rate(Gallons / Hours)Flow Rate Needed for 8-Hour Turnover Rate
(Turnover / 60 Minutes)
10,0001,666 GPH28 GPM1,250 GPH21 GPM
20,0003,333 GPH56 GPM2,500 GPH42 GPM
30,0005,000 GPH84 GPM3,750 GPH63 GPM
40,0006,666 GPH111 GPM5,000 GPH84 GPM
50,0008,333 GPH139 GPM6,250 GPH104 GPM
60,00010,000 GPH167 GPM7,500 GPH125 GPM
70,00011,666 GPH194 GPM8,750 GPH146 GPM
80,00013,333 GPH222 GPM10,000 GPH167 GPM
90,00015,000 GPH250 GPM11,250 GPH188 GPM
100,00016,666 GPH278 GPM12,500 GPH209 GPM

Here’s a quick step-by-step for an easy reference, and then we have described what we are calculating just below that:

  • Step 1: Calculate the total pool volume
  • Step 2: Divide the result of Step 1 by 6 or 8 (hours)
  • Step 3: Divide the result of Step 2 by 60

Step 1 - Calculate the Total Pool Volume

If you don’t know how much water is in your pool, that link will take you to a guide that will tell you how to calculate your pool's volume. Don’t worry, it is simple geometry, and we will walk you through the process.

Step 2: How Many Gallons Per Hour

If you choose to filter your pool water 3 times per day, you will need to filter your pool’s water every 8 hours. That means that you need an 8-hour turnover rate. Dividing the pool’s volume of water by 8 will give you the number of gallons you need to filter each hour to achieve that rate. Don’t worry if this doesn’t make sense. We’ve made a chart to simplify this process.

Step 3: How Many Gallons Per Minute - Pool Pump Setting

Pool pump settings use Gallons Per Minute (GPM) rather than Gallons Per Hour (GPH), so we need to divide our Step 2 result (Gallons Per Hour) by 60 (Minutes) to find the correct pump setting.

Flow Rate and Filtration Considerations

Debris in the Filter / Old Filters

If you picture yourself breathing through a straw, you will probably imagine the headache forming from all the effort to inhale that life-giving oxygen. In a similar way, accumulating debris in the filters increases the required pressure for a pool pump to circulate the same amount of water.

It’s a good practice to keep an eye on the pool pump pressure. Make a note of the pressure when the filters are clean. When the PSI number climbs up by 8 points, it’s time to clean them. If this pressure change happens within 6 months, that is usually an indication that you need a new filter. Typically, these filters only need to be changed once every 3 to 5 years, so they’re more like to need cleaning than swapping.

What Type of Filter Are You Using?

When it comes to water flow, the type of filter you are using is going to make a difference. Cartridge filters and sand filters are not very efficient, you need to clean them more often, and they slow down the water flow more than their Diatomaceous Earth (D.E.) pool filter counterparts.

D.E. pool filters don’t require as many turnovers as the other two types of pool filters because they can filter water down to much smaller particle sizes. This means that fewer contaminants get through, so you don’t need to strain the water so much. It also means that you don’t need to treat the water with the same amount of sanitizer, so you can spend less time balancing the chemicals. On the downside, D.E. filtration systems do require more maintenance.

Water Treatments

If you are on top of your chemical balancing game, your pool filter will not have as many contaminants to clog up the flow. The algae nomads will have a harder time developing into colonies. Your filtration system won’t be overrun, its flow rate won’t be compromised, and its lifespan will not be reduced.

Cheapest Time of Day to Run the Pump

If you can’t afford to run the pump all day long, you should check if your power company charges different prices for peak and non-peak hours. A lot of power companies do have these programs. A lot of families can save hundreds per year by being a bit pickier about when they clean their clothes or wash their dishes. The pool pump alone won’t make that sizable of a difference, but you can still save a chunk of change.

Water Pump Types, Horsepower, and Turnover Time

If you want an in-depth breakdown of how to choose the right pool pump for your pool, we actually wrote an article covering that very topic. It goes over the cost factors, required horsepower, features, repair costs, and the pros and cons of popular water pump brands.

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