How to clean a hot tub filter: an easy step-by-step guide

Need to know how to clean a hot tub filter? Take advice from the experts to keep your outdoor spa in top condition

how to clean a hot tub filter - built-in hot tub on deck
(Image credit: Concept Spa)

Knowing how to clean a hot tub filter is essential if you’re to keep the hot tub water both clean and clear. The filter traps dirt and debris to prevent it contaminating the water, and regular maintenance is a must to ensure it keeps doing its job effectively.

Rest assured that cleaning the hot tub filter takes little effort, and it’s a straightforward task, too. What is important is doing the job regularly so it can play its part alongside chemicals and sanitizers in keeping the water healthy.

Whatever your hot tub ideas, discover how to keep the water pristine with our step-by-step guide and expert advice on cleaning a hot tub filter.

Follow our 3 easy steps for how to clean a hot tub filter

Once you’ve selected yours from among the best hot tubs, you’ll need to get savvy about maintaining your choice – including its filter. 

‘High-quality hot tub filters are designed with a molded plastic core and a pleated polyester material that catches the dirt,’ explains Sallie Leslie-Golding from BISHTA (The British and Irish Spa and Hot Tub Association). ‘The pleats of the filter material increase its surface area allowing for more dirt to be contained.’ 

It’s the particles trapped in the filter you need to remove, so here’s how to clean a hot tub filter.

1. Rinse the hot tub filter weekly

The first step in how to clean a hot tub filter is rinsing it weekly. You can do this using a garden hose, and the process will get rid of the large debris the filter has trapped.

As with any part of cleaning a hot tub, make you switch off the hot tub first. Next, remove the filter following the tub manufacturer’s instructions. Using the hose, rinse the pleats of the filter. 

Leave the filter to dry completely and then replace. 

filter in an inflatable hot tub

Remove the filter from the hot tub following the manufacturer's instructions

(Image credit: Pixinoo/iStock/Getty Images Plus)

2. Deep clean a hot tub filter

While rinsing the hot tub filter weekly is an important part of hot tub maintenance, knowing how to clean a hot tub filter correctly means you need to get savvy about deep cleaning it too. As for how frequently this should take place? ‘Depending on how often you use your hot tub, we recommend cleaning your filter twice a month,’ advises Tim Snelling, sales director at Hot Tub Hub.

Soaking the hot tub filter in a filter cleaning solution will deep clean it, removing contaminants including bacteria and oils. Turn off the hot tub first then remove the filter. Rinse as above in order to remove any large pieces of debris from the filter before deep cleaning.  

Prepare the filter cleaner in a bucket according to pack instructions and put the filter in to soak, leaving it overnight. 

Rinse the filter thoroughly after soaking. Allow to dry completely before replacing it. 

Always make sure you check the hot tub manufacturer’s instructions on filter care when choosing a cleaning product.

hot tub filter and cleaning solution

Deep cleaning your hot tub filter with the appropriate cleaning solution is essential for ongoing maintenance

(Image credit: Pixinoo/iStock/Getty Images Plus)

3. Swap filters regularly

It’s essential that you don’t use your hot tub when the filter is not in place as debris could damage the spa. But that means removing the filter for cleaning will prevent its use. The solution? A filter swap.

‘The filter material is resistant to acids and other chemicals and can be expected to last up to 18 months,’ says Sallie Leslie-Golding. ‘It is advisable to have two sets of filters used on a month on/month off rotational basis so that you always have a clean set ready to go back in when the other set is removed for deep cleaning (to reduce the downtime of your hot tub). 

‘If you are not rotating your filters, they should be replaced with a new set every 12 months; whereas those used on a month on/month off rotational basis can be replaced for new ones every 24 months.’

Don't forget that as well as regularly changing filters, knowing how to shock a hot tub and how to drain a hot tub correctly should also be part of your ongoing hot tub care. 

Hot tub filter cleaning mistakes and how to avoid them

Not every spa owner knows how to clean a hot tub filter the right way. These are the errors the experts see most frequently so you can avoid them.

  • Rinsing the hot tub filter with a pressure washer: ‘As tempting as it seems, we would not recommend using a pressure washer to clean your hot tub filter as this may damage the filter,’ says Tim Snelling. Sallie Leslie-Golding agrees. ‘A power jet washer should never be used to clean filters as the power of the jet will damage the fibers of the weave in the fabric of the filter and render it useless,’ she says. The way to avoid problems? ‘Hose down the filters using a garden hose with good jet pressure to clean off the large and loose debris caught between the pleats,’ Sallie says. ‘Either put your thumb over the end of the hose to increase the pressure of the water jet or use a hot tub filter brush hose attachment.’
  • Using the wrong cleaners: Always use a hot tub filter cleaning product recommended by your tub’s manufacturer. ‘It is also important not to use them with household detergents or any chemicals that could affect the balance of the water,’ says Tom Drakett-Cain, brand marketing manager at Lay-Z-Spa of the filters. So that’s a definite no to dish soap, laundry detergent, vinegar and bleach, all of which you may see recommended online. Don’t put the hot tub filter into the dishwasher either.

cleaning a hot tub with a hose

(Image credit: Igor Vershinsky/iStock/Getty Image Plus)

Why is it important to clean a hot tub filter?

Cleaning a hot tub filter regularly is important because of the job it does. ‘Hot tub filters work in conjunction with the hot tub’s pump,’ explains Tom Drakett-Cain. ‘As the main part of any circulation system, the pump pulls water from the hot tub, through the filter, before returning the newly filtered water into the hot tub. Whilst doing so, it collects small particles of dirt or debris and helps keep the water clean and clear.’

Cleaning the filter removes what it has caught. ‘If not regularly cleaned, the particles of dirt and debris remain trapped in the filter,’ says Sallie Leslie-Golding. ‘They will eventually start to reduce the filter's effectiveness and the cleanliness of your water. Your sanitizer will be used up more rapidly, killing germs in the debris in the filter, rather than in the main body of your hot tub water where it’s actually needed.’

Note that there are variations in filtering between different hot tubs. ‘The amount of water pumped through the filtration system will vary depending on the make and model of the hot tub and the type of circulation/filtration system it employs,’ says Sallie. Always be sure to check the manufacturer’s instructions on filter care.

Adding suitable hot tub shelter ideas to your outdoor spa space can be a good way to reduce the amount of dirt and debris that gets into your hot tub filter too. 

Sarah Warwick
Freelance writer

Sarah is a freelance journalist and editor writing for websites, national newspapers, and magazines. She’s spent most of her journalistic career specialising in homes and gardens and loves investigating the benefits, costs and practicalities of home improvement. It's no big surprise that she likes to put what she writes about into practice, and is a serial house revamper.