How to Clean a Cartridge Filter

Note: A newer and more up-to-date version of this article can be found here.

One advantage of having a cartridge filter is the lack of continuous maintenance it requires. Unlike a sand filter that needs to be backwashed multiple times per month, a cartridge filter only needs to be cleaned a few times per year. Ideally, if you clean your filter at least four times per year, the life of the cartridge elements will be extended.
When a cartridge filter needs to be cleaned, it can be a tedious process. The steps are simple, but it can take a lot of time to clean it properly.


The following steps show you not only how to clean a cartridge filter, but how to clean it efficiently.

    1. Shut the system off. This should be the case when working with any type of pool equipment.
    2. First things first. You'll want to bleed the air slowly from the filter by turning the air relief valve, typically on the top of your filter. Next, remove the clamp that holds your filter together. Different brands may have different mechanisms, but either way, it needs to be removed. Documentation that comes with your filter will teach you how to properly remove it. If that documentation is not available, you can take a picture of your system and show it to a Leslie’s professional at a local store.
leslie's retail store locator


    1. Once the clamp is removed, carefully take off the top section of your cartridge filter to expose the cartridge elements inside.
    2. There may be some part holding these cartridges in place, but the specific build will vary by brand and model. If this is present, it needs to be removed before taking your cartridge elements out. Again, if you are unsure how to remove this, refer to the product documentation or ask a Leslie’s professional.
    3. Carefully take out the cartridge elements and set them aside. Check each cartridge for potential damage that may have been caused. If there are any cracks in the plastic housing or tears in the pleats, it is strongly recommended to replace the filter cartridge. Even a small tear can decrease the effectiveness of the filter.
leslie's replacement pool filter cartridges


  1. Use a degreaser like Leslie’s Spray and Rinse Filter Cleaner. Thoroughly coat the cartridge elements, making sure you also get the product in between the pleats. This product can simply be sprayed onto the cartridge. Follow product instructions for how long to keep this product on the elements before rinsing it off. Other products such as Leslie’s Cartridge Cleaner require you to soak your elements overnight instead of spraying the product on them.
  2.  Products like the Filter Flosser can be used as an attachment to a garden hose to effectively rinse in between the pleats on the cartridge element. This is where most dirt and debris is found, so it is important to clean this area. A simple garden hose can also be used, using your thumb to increase water pressure.
  3. Once all of your cartridge elements are clean, securely replace all elements and parts in the proper place.
  4. Check the O-ring that is in place on the filter tank. If it appears dry-rotted or too flat, it may need to be replaced. Bring the O-ring into a local Leslie’s store to check. If your O-ring is in good shape, a light layer of silicone-based lubricant should be used to coat the O-ring.
  5. Securely replace the tank lid and tightly close the clamp that holds it together.
  6. Double-check that everything is properly closed and in place before turning on your system to ensure everything is running properly.
  7. Once your system is running, open up the air relief valve at the top of your filter tank to release any excess air in the system. Leave this open until water consistently sprays out of the valve.
  8. Once the air is out of your system, take note of the filter pressure using the gauge on top of the filter (measured in pounds per square inch [PSI]) to make sure it is in the proper range. This range can vary based on the configuration of your system, so if you are unsure what your filter pressure is typically at when clean, check with a local Leslie’s professional. If the PSI seems off, something may have been put back together incorrectly or there may be another problem with the system.
  9. Shut off the system.

At any point during the cleaning process, a Leslie’s professional is available at your local store to answer any questions you may have.

Facebook  Twitter  YouTube  Instagram