How to Clean Your Pool Filter

The pool filter is critical in providing a safe, enjoyable experience for you and your family. Cleaning your pool filter is an essential part of your maintenance routine! If your filter is dirty, it will be significantly less effective and could result in some nasty cleanup later. Whether you’re a new swimming pool owner or are looking for a refresher course, let’s go over how to clean your pool filter step-by-step, according to what kind of filter you have.

Main Takeaways

• You should clean your filter when the pressure gauge reads 8-10 psi above the normal range or when you have cloudy pool water.
• You should replace the sand in your sand filter every 5-7 years.
• Cartridge filters should be cleaned every 6 months and replaced every 3-5 years.
• D.E. filters must be cleaned every year.

How to Clean Sand Filters

First and foremost, cleaning a sand filter requires knowing when the filter should get cleaned. Your pool gives two leading indicators: a reading on the pressure gauge 8-10 PSI above the average operating level (which varies depending on the filter) or cloudy pool water. When either of these conditions develops, it’s time to follow the steps below. It’s also good to get in the habit of replacing your sand every five to seven years.

Gather the Equipment

• Backwash hose
• Sand filter cleaner
• Filter owner’s manual

Cleaning a sand filter does not require much equipment, but the owner’s manual may come in handy if something goes wrong during the process.

Start Cleaning

• Turn off the pool pump. This step is crucial, as turning the valves on the filter with the pump still running can damage the internal components.
• Attach backwash hose, or unroll if already attached to the waste line, and open the waste line valve.
• Turn the valve on the filter to the “backwash” setting.
• Turn on the pump to get the water moving backward through the filter.
• Run the pump on the backwash setting until the water flowing from the waste line runs clear – usually just a few minutes.
• Turn off the pump.
• Turn the valve on the filter to the “rinse” setting to resettle the sand.
• Turn the pump back on and rinse for 30-45 seconds.
• Turn the pump back off.
• Turn the valve on the filter to the “filter” setting.
  • Once a year, remove the filter basket during this step and pour in the sand filter cleaner.
  • Turn on the pump just long enough to move the cleaner into the sand.
  • Turn off the pump and let the sand soak in the cleaner for 8 hours or more.
  • Repeat the backwash process to remove any material dislodged by the sand filter cleaner.
• Turn the pump back on.

How to Clean Cartridge Filters

Like sand filters, you need to clean cartridge filters whenever the pressure gauge rises 8-10 PSI above its normal operating levels. Even if the pressure stays at a reasonable level, cartridge filters should be cleaned at least every six months and replaced every 3-5 years.

Gather the Equipment

• Garden hose
• Spray nozzle
• 5-gallon bucket
• Filter cleaner
• Silicone-based lubricant
• Owner’s manual

Start Cleaning

• Turn off the pump to avoid damaging equipment.
• Open up the air relief valve on the filter.
• Remove the housing containing the cartridge.
• Carefully remove the cartridge.
• Inspect for any signs of damage – tears or very soft pleats indicate it’s time to replace the cartridge.
• Use the garden hose and spray nozzle to rinse off the cartridge, making sure to get into all the small spaces between the pleats.
• If necessary, apply cartridge filter cleaner directly or soak the cartridge in the cleaner overnight in the 5-gallon bucket, depending on the type of cleaner used.
• Inspect the O-ring on the filter tank; if dry-rotted or damaged, replace it. If not, apply a thin layer of the lubricant.
• Return the cartridge to the housing and reassemble the filter.

How to Clean D.E. Filters

D.E. filter cleaning has a little more involvement. D.E. filters are cleaned both chemically and with a backwash like a sand filter. Check your local municipal guidelines for information on the disposal of spent D.E. These filters need to be backwashed once a month or whenever the pressure gauge rises to 8-10 PSI above the normal operating level.

You need to clean the grid assembly annually, making D.E. filters a little more time-consuming to maintain. But they create the cleanest pool water, so some users find the extra time and cost well worth it. Head to my guide on how much D.E. to add to your filter for more.

Follow the steps below to clean your D.E. filter.

Gather the Equipment

• Backwash hose
• Garden hose
• E. filter cleaner
• Silicone-Based Lubricant
• Replacement D.E.
• 5-gallon bucket

Start Cleaning

• Backwash the filter using the same instructions outlined for sand filters above.
• After backwashing, turn the pump off again.
• Open the air relief valve.
• Drain the water from the filter tank by removing the drain plug.
• Open the filter tank and remove the grids and manifold.
• Inspect the grids and manifold for signs of damage; replace them if anything looks wrong.
• Rinse out the filter tank with the garden hose.
• Rinse off the grids and manifold thoroughly, using a D.E. filter cleaner if necessary.
• Place the clean grids and manifold back in the tank.
• Inspect the O-Ring on the filter tank and replace it if damaged.
• If the O-Ring is in good repair, apply a layer of lubricant to keep it that way.
• Reassemble the filter.
• Add new D.E.
  • Follow the manufacturer’s instructions to mix the D.E. into a slurry.
  • Remove the strainer housing lid and fill the strainer housing with water.
  • Put the strainer housing lid back on.
  • Open the filter air-relief valve to remove air from the tank.
  • Turn on the pump.
  • Close the air-relief valve once the water starts flowing.
  • Slowly add the slurry directly to the skimmer with the pump running.

For more information on the cleaning process, head over to my complete guide on how to clean a DE filter.

Why is Cleaning Your Pool Filter Important?

The filter keeps your pool healthy. I covered a few different filters above, but the basic mechanics remain the same. While the most obvious function is filtering out large debris like leaves and bugs (which it certainly does), it also filters out finer things like dirt and dust, inviting more significant problems when left unchecked.

Pool filtration systems essentially force water through some type of material porous enough to allow water molecules through, but condensed enough to trap larger objects trying to pass through with the water. By doing so, they reduce the amount of “junk” floating around in your pool.

Filters that fail to trap all of the particles end up placing a heavier load on the pool sanitizer since the chemicals try to dissolve all of the unpleasant things like bits of leaves, dust, or dirt. If your filter is dirty and not as effective, the chemicals need to do more work, more chemicals may need to be applied, and your pool maintenance costs – both time and money – can go up. So, bottom line – get in the habit of cleaning your pool filter!

Final Thoughts

Clean filters are a crucial part of pool maintenance. Thankfully, most filter designs make it easy for homeowners to take care of it themselves with a little know-how. Follow the steps outlined in this article, and you’ll be back to sparkling water in no time.

If you need to replace your filter or are looking for more maintenance tips, be sure to read my guides on the best pool filters and regular pool maintenance.

Questions? Let me know; always happy to lend a hand.