How Often Should You Replace Your Swimming Pool Filter?

Your swimming pool filter is like the kidney of your pool: it filters out the debris and unwanted contaminants, leaving you with fresh, clean water.

Making sure your filter is working effectively is hugely important, regardless of whether you have an indoor swimming pool or a small, above-ground pool for summer. In this guide, we look at when to replace your filter system and how to keep your water cleaner for longer.


- How Do Pool Filters Work?
- How Often Should You Change Your Pool Filter?
- Signs Your Filters Need Replacing
- How Long Do Pool Filters Last?
- Tips for Pool Filter Longevity
- What Will Ruin a Pool Filter?
- When to Clean Your Pool Filters
- Choosing the Best Pool Filter

How Do Pool Filters Work?

Pool filters are really simple. A pump pushes water through a tight space that only allows clean water through, collecting any small dirt particles and removing them from the water via a filter media.

Types of Swimming Pool Filters

Various types of filters are available for swimming pools, and which is right for you often depends on your pool type and size.

Generally, swimming pool filters are divided into three categories:

- Cartridge Filters
- Sand Filters
- Glass Filters

A small pool, like a temporary above-ground pool or hot tub, often uses a filter cartridge. This filter is the simplest and cheapest option, making it perfect for smaller pools.

A filter cartridge is typically round like a barrel and made from polyester cloth or corrugated paper. Swimming pools with this filter will push water into the cartridge, trapping any dirt.

However, most swimming pools opt for filter pumps that employ sand or glass media. Here, the filter is part of the pump system itself, filtering any dirt as it passes through and returning clean water to the pool. One trendy model here is the Lacron sand filter

Sand filter media allows water to pass through a canister containing sand (usually silica or pool-grade sand, not just from the beach!). The smaller water particles will pass through, but the larger particles get stuck, providing clean water.

Glass filter media works in much the same way. However, glass filter media tends to be more efficient and can capture particles around 1/4 of the size of sand filters. Hence, they tend to be more effective.

Clean swimming pool water


How Often Should You Change Your Pool Filter?

You should change your pool filter whenever it loses its quality, has passed its expected lifespan or shows signs of damage. Symptoms often start to appear every five years, but the timescale can be anywhere between yearly and every 15 years, depending on the type of filter and your swimming habits.

When to Change a Sand Filter

Sand filter media can often perform for around three to seven years, depending on use.

If you frequently clean and backwash your filter and only use the pool seasonally, you can expect to replace it after at least five years. While sand filters can be good for a few more years, we recommend replacing your media at this point to maintain a healthy pool system long-term.

When to Change a Glass Media Filter

Glass filter media is known for its longevity – if well cared for, it might not need replacing for over a decade!

Glass filter media can last for way beyond the timespan of sand media. However, we also recommend replacing the media itself every five years to keep your pool systems working efficiently.

Shop now swimming pool filters glass and sand media

When to Change a Filter Cartridge

Usually, you can determine visually if your filter cartridge is working or not, but it’s always recommended to change it once its use by date has passed. Depending on the brand, this date is often after one or two years. If you see a tear in the filter, it will need replacing.

Two swimming pool pumps with clean filtered water

Signs Your Filters Need Replacing

As mentioned above, some symptoms of a poorly-working filter can be due to uncleanliness. However, there will often come a point when cleaning your filter isn’t enough, and it needs replacing.

Here are some of the signs to look for when considering a filter change:

Rapid Underperformance

If your filter gets clogged or stops cleaning more frequently than expected, it may have lost its quality even with frequent backwashing.

Use-By Date

Filter cartridges will often come with a use-by date due to their design. However, all filters have a predicted lifespan. If this is passed, then replace the filter.

Damaged Filter

This point applies to filter cartridges, which can tear over time. If this happens, you need to replace the filter.

An outdoor swimming pool

How Long Do Pool Filters Last? 

Your swimming pool pump system can expect to pump 60-70,000 gallons of water every 8 hours. That’s a lot of work!

Like all things, swimming pool filters become less effective with age! When the filter passes its prime, it will get clogged, dirty, and ineffective.

How long your pool filter will last depends on how much dirt it needs to clean. Assuming you properly maintain your swimming pool, you should expect the below timescales on average:

- Filter Cartridge – approximately 2,000 working hours, usually around 2-4 years.
- Sand Filter Media – around 3-7 years.
- Glass Filter Media – about 7-15 years.

Tips for Pool Filter Longevity

Ultimately, the lifespan of a filter depends on how much dirty water it needs to clean. If you want to increase your filter’s longevity, make sure you follow good general maintenance rules.

Managing Pool Water Quality

The most important thing is maintaining the right chemical balance daily. Having the correct swimming pool chemicals will stop algae from forming and help deal with other dirt and debris, putting less strain on your swimming pool filters.

While water clarifiers and similar products can make your swimming pool look clean, they can clog your filter. In the end, there’s no substitute for frequent chemical management.

Clean Swimmers

The more frequently a pool is used, the dirtier it’s likely to become.

Swimming pool users will bring contaminants into the pool, ultimately ending up in the filter. These can include body oils, shampoos, drinks and more.

If you want to care for your swimming pool, you can take steps to minimise the impact people have:


- Shower First - taking a shower before going in the pool will remove some of the contaminants that end up in the filter.

- No Food or Drink - encourage people to enjoy food or drink before or after the pool, not during their swim!


Caring for Your Pool Filters When Out of Use

Another thing to consider is what happens to your filters when the pool isn’t in use. If you use your small swimming pool seasonally, ensure your cartridge filters are stored correctly when out of season. Also, check them before the next season begins, as they can sometimes lose their quality over time, even when not in use.

Pump filter systems should still run occasionally during the off-season to keep the chemicals in the water ticking over. Therefore, you need to monitor your filters during periods of disuse. As with your pool as a whole, investing in a cover and properly closing your pool will also help keep your filters working efficiently.


A clean blue-tiled swimming pool

What Will Ruin a Pool Filter?

It’s vital that you maintain your pool’s pH and alkaline levels. If you don’t, you risk causing damage to your pool filter. Here are a few other things that can cause damage to your pool filter:

- Perfume
- Sunscreen/Body Lotion
- Too Much Chlorine
- Chemical Imbalance
- Age and Wear

Guide to pH Balancing for Swimming Pools

When to Clean Your Pool Filters

If your pool filter’s quality has decreased, it may not necessarily need replacing. All filters need regular cleaning to ensure they can work to their full capacity.

If you’re using a cartridge filter, remove it and rinse it off thoroughly with a stiff brush and hose, and use a specialist filter cleaner if available. Aim to do this once a week for the optimal longevity of your filter.

Head over to our guide to find out more about how to clean pool cartridge filters

To care for a glass or sand-based pump filter system, you perform a procedure known as backwashing. Most pump systems will come with a backwash option, allowing water to run through the opposite way to before, lifting clogged dirt from the filter.

You should look to backwash your pool filters whenever the pressure has risen from its normal levels by around eight-to-ten psi. During heavy use, this will happen every week, sometimes more frequently.

Choosing the Best Pool Filter

The filter is crucial to your swimming pool, so you must get a quality unit. Making sure you choose a good swimming pool filter will save you a lot of money and effort long-term, so it’s worth exploring a couple of options.

Home Pool Filters

When it comes to home pool filters, they often fall into two categories:

- Side-Mount Filters
- Top-Mount Filters

These are essentially the same thing, except the valves and other features are either on the top or side of the filter. Whether you need a top or side-mounted filter often comes down to how your pool is set up – it should be clear which will fit.

Many home filters will come with the same features, so the most important thing to note is the pressure. Ensure that the filter system you choose can cope with the force of your pool pump. Also, ensure that it’s a solid build as any cracks will cause a significant headache.

One outstanding option is the PerAqua Side Mount Filter. This model is as good as it gets when it comes to durable, expertly designed-swimming pool filters.

Shop now Peraqua swimming pool filters

Another model we highly recommend is the Tagelus Top Mount Filter. Again, this is a durable model designed for maximum reliability and easy maintenance, making it a great choice for owners with less pool experience.

Shop now Tagelus Top Mount Filter

Commercial Pool Filters

Commercial swimming pools have additional requirements when it comes to pool filters. First of all, they are usually bigger and used more frequently, so the pressure is more intense. However, there are also issues like the time and regularity of use. The filter needs to be continuously maintained, much more so than with a home pool.

If you operate a small commercial swimming pool, we recommend the Lacron 24 Finaflow MBF. This model works with a running pressure of 2.5 bar and a flow rate of 15m3/hr, and is also equipped with a handy sight glass, allowing for checks during operation.

Shop now Lacron 24 finaflow MBF

Filter Media

The vast majority of filters will require you to purchase the media separately, as this will need to be replaced more often than the actual mechanics.

Most filters that can work with sand media will also work with glass. If your filter uses a cartridge, you’ll need to continue using a cartridge.

Generally speaking, sand filter media is a good choice in most circumstances. However, if you’re willing to pay more, glass filter media is more effective at cleaning small particles and can last longer, so it’s often worth the investment.

1st Direct Pools supply everything you need to keep an immaculate swimming pool. From swimming pool filters, sand and glass filter media, pool and hot tub chemicals and much more, we’re your one-stop-shop for all things swimming pools. 

Shop now swimming pool parts and accessories