how long to run inground pool filter


Author: Poolking - Swimming Pool Equipment Manufacturer

Keeping a clean and healthy swimming pool that everyone can enjoy requires proper maintenance. And one of the crucial components of this maintenance is the pool filter. An in-ground pool filter is responsible for removing dirt, debris, and contaminants from the water, retaining it in the filter, and sending clean water back into the pool.

So how long should you run your in-ground pool filter to keep your pool sparkling clean and safe to swim in? The answer ultimately depends on several factors, including the size of your pool, the type of filter you have, and the environment around your pool. In this article, we’ll dive deep into how long to run your in-ground pool filter, and provide some useful tips and tricks to help you take care of your pool.

How Pool Filtration Works

Before we delve into how long you should run your in-ground pool filter, let’s take a moment to understand how pool filtration works. Pool water is drawn into the filter, which contains a series of cartridges, sand, or even diatomaceous earth (DE). Unfiltered water passes through these materials, and contaminants are trapped in the filter media.

The water then returns to the pool, and the process begins again. It’s similar to how our kidneys filter our blood, removing impurities and toxins and sending clean blood back to the body.

The Importance of Running Your In-Ground Pool Filter

Pool filtration is crucial for maintaining clean and clear water, and it’s critical for your pool’s health. Failing to run your pool filter enough can lead to the growth of algae and bacteria in the water, which can cause health problems for swimmers.

Chlorine, a common sanitizer used in pools, works better when the water is clean and clear. If the pool water is dirty, it will require more chlorine to maintain its sanitizing properties, which can result in high chlorine levels and irritation to swimmers’ skin and eyes.

How Long Should You Run Your In-Ground Pool Filter?

As we mentioned above, the duration you should run your pool filter depends on many factors. Here are a few essential factors to consider when determining how long to run your in-ground pool filter.

1. Pool Size

The size of your pool is one of the critical factors to consider when determining how long to run your pool filter. Larger pools require longer filtration periods than smaller ones. A good rule of thumb is to run the pool filter at least eight hours a day for a pool up to 20,000 gallons.

For larger pools, you need to run your pool filter for an additional hour for every 10,000 gallons of water. So, for a pool between 20,000 and 30,000 gallons, you should run the pool filter for nine hours, ten hours for a pool between 30,000 and 40,000 gallons, and so on.

2. Type of Filter

The type of in-ground pool filter you have will also play a significant role in determining how long it should run. Generally, cartridge filters require less maintenance than sand or DE filters.

However, cartridge filters tend to get clogged quickly and need to be cleaned more frequently than other types of filters. On the other hand, sand filters require the least maintenance, but they need backwashing every few weeks to remove debris from sand beds.

DE filters usually filter out the smallest particles and are the most efficient type of filter, but they require more maintenance, including backwashing and adding DE powder regularly.

3. Weather Conditions

Weather conditions can also affect how long you should run your pool filter. In the summertime, when temperatures are high, and pool usage is at its peak, you may need to run the filter for longer periods to keep up with the heavy bather load and the high temperatures.

However, colder temperatures or heavy rainfall may decrease the number of debris or contaminants in the water, allowing you to run the pool filter for less time.

4. Pool Usage

Pool usage is a crucial factor in determining the filtration time. The more people use the pool, the more debris, oils, and other contaminants enter the water. If your pool sees heavy use or a lot of splashing, you may need to increase filtration time to keep the water clean.

Also, if you use any pool cleaning chemicals, such as algaecides or clarifiers, it’s best to run the filter for a few days after use to remove any residual chemicals.

5. Maintenance and Cleaning Schedule

Finally, the maintenance and cleaning schedule of your pool can affect how long you need to run the pool filter. If you are staying on top of the pool’s maintenance and performing regular cleaning, it will require less run time on the pool filter.

Maintaining proper pH levels and chlorine levels can go a long way toward keeping the pool clean and reducing the amount of time required for filtration.


In conclusion, the duration you should run your in-ground pool filter depends on several factors, including the size of your pool, the type of filter you have, and pool usage. Running the filter for the recommended amount of time ensures that pool water remains clean, clear, and safe to swim in. Always check the manufacturer’s instructions for your filter and pool, and follow their recommendations. With proper filtration and maintenance, you can enjoy a clean, sparkling pool year-round!


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