Blog Header Image

How To Clean Your Pool's Cartridge Filter

Clean, clear, healthy, safe … these are words we like to see associated with water. This applies to pool water too. After all, who doesn’t want the highest quality water possible to swim in? One of the most important factors in keeping your pool water beautiful, healthy, and safe is your filter. Many pools use cartridge filters, which are effective and easy to maintain. To get the most from your filter, it's important to know how to properly clean a cartridge pool filter.

Cartridge filters use a cylindrical fan-folded polyester cartridge as the filtering medium. Water flows through the fabric and traps debris. Cartridges can last 3-4 years before needing to be replaced, depending on pool usage, water chemistry, and maintenance practices. A key part of those essential maintenance practices is cleaning your filter cartridges.

Depending on manufacturer recommendations, you should clean your cartridge filters when either of these situations arise:

Leslie's Pressure Gauge

The filter pressure gauge reading goes up 8-10 PSI above the clean starting pressure.

Leslie's Calendar

It has been 3-6 months since the last time you cleaned your filter cartridges.

Now on to the main attraction. Here are the steps for cleaning your cartridge filter, as well as the tools and supplies needed:

Cleaning a Cartridge Pool Filter

A cartridge filter is relatively easy to clean. The process consists of pulling out the cartridges, cleaning them, and putting them back in. But there are a few steps to follow to make sure it’s done right. Ready? Ready.


  • Garden hose
  • Spray nozzle
  • Filter cleaner
  • Large bucket (if needed)
  • Non-petroleum -based lubricant

  • Replacement filter tank O-ring (if needed)
  • Replacement filter cartridges (if needed)
  • Rubber mallet (for multi-element filters)
  • Owner’s manual (just in case)

DIY TIP: Be sure to keep all necessary supplies on hand so you’re always ready to clean your cartridge filter as soon as you notice it’s not working properly.


  1. Turn off your pool pump at the breaker.
  2. Remove air from the system by slowly opening the air-relief valve (usually located on top of the filter) to remove any excess air from the system.
  3. Remove the clamp or assembly holding the filter together. Your owner’s manual might come in handy here.
  4. Remove the top of the filter.
  5. Slowly and carefully remove the cartridges and set them aside. Inspect everything for damage and wear. If you find any cracks or tears, or if a cartridge is mushy, it’s time to replace the cartridge.
  6. Clean the cartridge using a spray nozzle on your garden hose — spray at an angle to get between the pleats. Never use a pressure washer; it will damage the cartridges.
  7. If the cartridge is really dirty, use a filter cleaner. Follow the manufacturer’s instructions.
  8. If the cartridge is really, really dirty, soak it in filter cleaner overnight. Use a five-gallon bucket or clean plastic trash can, and make sure the cartridges are completely submerged in the water and cleaner mixture.
  9. Next, check the filter tank O-ring on the filter tank. If it’s in good shape, lightly apply some lubricant to keep it that way. If it’s dry-rotted, deformed, stretched, or appears worn out, replace it.
  10. Rinse the cartridges thoroughly.
  11. Return the cartridges to the filter and secure them in place.
  12. Replace the filter top and tighten the clamp or assembly. You may need to tap the clamp with a rubber mallet while tightening to ensure it's sealed properly.
  13. Make sure your air-relief valve is still open to release any excess air in the system. Turn the system back on. Keep the valve open until a steady stream of water sprays from it, then close.
  14. Check the system pressure to ensure it’s in normal range. If the pounds per square inch (PSI) is off, you may have put the filter back together incorrectly, or something else may be wrong with the system. Troubleshoot the pool filter to identify and correct the problem.

SAFETY TIP: Always wear recommended/required safety equipment and follow manufacturer’s recommendations for filter cleaning, maintenance, and proper operation.

It’s important for us to acknowledge that certain aspects of pool care are subjective, based on personal preference. There are many variations of successful approaches, but we have devoted decades to honing our products and solutions. If you have any questions, stop by your nearest Leslie’s store or call us at 1.800.537.5437.

At Leslie’s, we’re here to help you create your perfect pool

Facebook  Twitter  YouTube  Instagram