How to Clean a Pool Filter

Cloudy water, reduced flow or a pump that seems to be working harder? In many cases, the cause is a dirty pool filter. Cleaning your filter in time keeps the water clearer, helps your system run more efficiently and extends the lifespan of your installation, which also helps with an energy-efficient pool. Whether you have an Intex or Bestway cartridge filter, or a sand filter with sand, glass or filter balls: the right cleaning method differs by system.

Which filter system do you have?

Smaller above-ground pools often have a cartridge filter with a replaceable cartridge. You remove it from the filter pump and rinse it out. Larger pools more often use a sand filter. In that case, you usually do not clean the separate filter element, but the filter tank by backwashing. If you are still deciding between the two systems because you want to buy a pool, look not only at the purchase price, but also at ease of maintenance and how intensively you will use it.

How often should you clean a pool filter?

There is no fixed rule that is right for every pool. Usage, outdoor temperature, sun cream, leaves and the number of swimmers all make a big difference. So treat these intervals as a practical guideline, especially during peak season.

Cartridge filter or paper cartridge

Cleaning: Check every few days and rinse at least weekly

Replacing: On average every 2 to 4 weeks, or sooner if worn

Sand filter

Cleaning: Backwash as soon as the pressure rises or about every 2 to 6 weeks

Replacing: Filter sand usually every 3 to 5 years

Filter glass

Cleaning: Backwash as with sand filters

Replacing: Often only after 5 to 10 years

Filter balls

Cleaning: Rinse or wash regularly according to the manual

Replacing: On average after 2 to 4 years

Clean a cartridge filter with a garden hose

Cleaning a cartridge filter is simple, which is why it is popular for compact pools. First switch off the pump and unplug it. Open the filter housing, remove the cartridge and rinse between the pleats with a garden hose from top to bottom. This pushes dirt out rather than deeper into the material. If you see grease, oil or limescale, first soak the filter in a suitable pool cartridge filter cleaner and then rinse it thoroughly again. If the paper is torn, the cartridge stays grey or the flow does not recover, it is better to replace it than keep cleaning it. That also applies to many Intex and Bestway filters.

Clean a sand filter by backwashing

A sand filter, glass filter or filter tank with filter balls is usually cleaned by backwashing. This reverses the water flow so built-up dirt is flushed from the filter tank to waste. This is the standard method when the pressure gauge reads higher than normal or when the flow drops noticeably.

1. Switch off the pump.
2. Set the multiport valve to Backwash.
3. Start the pump and let it run until the sight glass or waste water runs clear.
4. Switch the pump off again and briefly select Rinse.
5. Then set it back to Filter and restart it.

If you use filter balls, also check the instructions for the material itself. Some versions can be rinsed or washed separately, while others are mainly maintained by backwashing.

When cleaning is no longer enough

A filter will not last forever. Replace a cartridge filter as soon as the pleats become limp, show tears or remain permanently clogged. With sand filters, you often notice worn filter media from persistently cloudy water, short filter cycles or pressure that rises again quickly after backwashing. Do not wait too long: fresh filter media works more efficiently and reduces the load on the pump.

Frequently asked questions

Can you put a pool filter in the dishwasher or washing machine?

A cartridge filter or paper filter should not go in the dishwasher or washing machine. Heat and mechanical stress can damage the material. Filter balls can sometimes go in the washing machine on a gentle cycle without detergent, but only if the manufacturer explicitly allows it.

Can you clean a pool filter with soda?

Soda is often mentioned online, but it is not a first choice for pool filters. It is better to use a cleaner designed for filter media. That reduces the chance of residue in the system and damage to the filter.

Why does my pool filter clog quickly?

This is usually caused by a combination of heavy use, pollen, sun cream, insufficient circulation or water that is out of balance. A filter pump that is too small or a filtration time that is too short can also cause your filter to clog up noticeably quickly.

How do I clean the filter in my pool pump?

Always start by switching off the pump. Then clean the correct part: rinse the cartridge if you have a cartridge filter, or backwash if you have a sand filter. If your pump has a pre-filter basket, remove that as well and rinse away leaves and debris before putting everything back.