To clean a hot tub filter, turn off the pump, remove the filter, and rinse it thoroughly from top to bottom with a hose. For a deeper clean, soak it in a dedicated filter cleaning solution overnight, then rinse well before refitting. Clean filters regularly to maintain water clarity, pump performance, and filter longevity.
Your hot tub is supposed to be the highlight of your garden — the place you go to switch off, soak, and feel like a functioning human again. So when the water starts looking a bit cloudy, or the flow drops off, it's a bit of a mood-killer. Nine times out of ten, a dirty filter is to blame.
The filter is what keeps your water clean and your pump happy. It catches oils, debris, skin cells, and whatever else finds its way in, and if it's clogged, the whole system works harder and performs worse. Knowing how to clean a hot tub filter properly — and how often to do it — is one of the simplest ways to protect your investment and keep your soak sessions exactly how they should be.
The good news? It doesn't take long. Here's everything you need to know, from a quick rinse to a proper deep clean.
What you'll need to clean hot tub filters (no fancy kit required)
You don't need a specialist toolkit for hot tub filter cleaning. Most of what you need is probably already knocking around in the shed:
- A hose with a spray nozzle (or a bucket if you're feeling committed)
- A large bucket or tub for soaking
- Dedicated filter cleaning solution (more on this below)
- A soft brush — optional, but useful for stubborn debris between pleats
- Gloves — also optional, but your hands will thank you
Before you start, it's worth checking your filter's manufacturer guidance. Different filter types and materials can have specific requirements, and what works for one won't always suit another.
The quick routine clean (10–15 minutes)
This is your bread-and-butter maintenance — something you should be doing regularly to stay on top of things.
Step 1: Turn everything off
Switch off the pump and power to the tub before removing anything. It's simple safety, and it stops any debris getting pulled into the system while you're working.
Step 2: Remove the filter(s) carefully
Some tubs have one filter, some have two. Take them out gently — no need to wrestle with them.
Step 3: Rinse from top to bottom
Work down the pleats (the accordion-like folds) with a firm spray, being careful not to drive debris deeper into the fibres. A hose nozzle set to a medium pressure is ideal. Don't be tempted to blast it with a pressure washer — it's far too aggressive and will damage the filter material.
Step 4: Inspect while you're at it
Have a look for fraying, collapsed pleats, cracks, or anything that looks a bit worse for wear. Catching problems early saves you hassle later.
Step 5: Refit and restart
Once you're happy, pop the filter back in, restore the power, and you're done. Job sorted.
The deeper clean: when a rinse isn't cutting it
If your water's been persistently cloudy, you're noticing reduced flow, or the filter looks like it's been through a muddy festival, a deeper clean is in order. This is where you leave it to soak.
Option A: dedicated filter cleaner (what we'd recommend)
The best hot tub filter cleaner is one specifically formulated for spa and hot tub cartridges. These are designed to break down body oils, sunscreen residue, and mineral deposits without damaging the filter fibres or leaving behind residue that causes foaming.
To use one:
- Fill a large bucket with water
- Add the filter cleaner according to the product instructions (dosage varies by brand)
- Submerge the filter fully and leave it to soak hot tub filter overnight — or for a minimum of six hours if you're short on time
- Remove and rinse very thoroughly — leftover cleaner in the pleats will cause foam once the tub is running again
- Allow it to dry slightly before refitting if you can (and keep a spare filter handy for this reason)
Option B: household alternatives (use carefully)
White vinegar works reasonably well for mineral scale and calcium build-up — soak the filter in a diluted solution for a few hours, then rinse thoroughly. Mild detergent can help with oily residue, but use it very sparingly. Whatever you use, rinse it out completely. Any soap residue left behind will cause a foam party in your tub — and not the fun kind.
Avoid anything with strong bleach, heavy chemicals, or anything designed for laundry. The filter fibres aren't built for it, and you'll shorten their lifespan significantly.
How often should you carry out hot tub filter maintenance
There's no universal answer, but here's a sensible guide for how often to clean your hot tub filter:
- Quick rinse: Once a week or every fortnight, depending on how often you use it
- Deep soak: Around once a month under normal use — more frequently if multiple people use the tub regularly, or if lotions, oils, and outdoor debris are a factor
- Filter replacement: Every 12 to 24 months, depending on the filter quality and how well it's been maintained — though signs of wear should always take priority over a schedule
The honest answer is that frequency depends on your setup, your water source, and your habits. When in doubt, clean it sooner rather than later.
Signs your filter needs replacing, not cleaning
Sometimes a clean won't cut it. Look out for:
- Pleats that stay grey or brown even after a proper soak
- Visible tears, cracks, or flattened sections that won't bounce back
- Persistent low flow or a pump that seems to be straining
- Water that won't stay clear no matter how well-balanced your chemicals are
- A stale or unpleasant smell that reappears straight after refitting
If you're ticking more than one of these boxes, it's time for a new filter.
Common mistakes (we've all been there)
A few things to avoid:
- Pressure washing the filter. Feels efficient. Destroys the fibres. Don't.
- Using washing-up liquid like it's a bath sponge. A little might be fine; half a bottle will create foam for days.
- Not rinsing thoroughly after soaking. This is the one that catches people out most often. Rinse like you really mean it.
- Putting a clean filter back into poorly balanced water. You'll undo all your hard work within hours — sort the water chemistry first.
- Forgetting the second filter. If your tub has two, clean both.
Extra tips for wood-fired hot tub owners
Outdoor tubs — especially wood-fired ones — tend to pick up more organic debris than indoor spa setups. Leaves, pollen, insects, and general garden matter will all end up in your water if you're not careful.
A few simple habits make a real difference:
- Keep the lid on when the tub's not in use
- Skim visible debris off the surface before firing up
- Rinse the filter a little more frequently during autumn or if you're near trees
- Encourage everyone to rinse off before getting in (body oils and lotions are tough on filters)
These small habits reduce the load on your filter and mean your water heats up faster and stays cleaner for longer — which is exactly what you want when you've spent an evening getting a wood fire going.
Quick checklist
✅ Rinse filter regularly (weekly or fortnightly)
✅ Deep soak monthly, or when performance drops
✅ Rinse cleaner out thoroughly before refitting
✅ Check for wear and damage each time
✅ Replace every 12–24 months, or sooner if needed
✅ Keep water balanced alongside filter maintenance
Frequently asked questions
How do I clean a hot tub filter at home without a specialist cleaner?
You can rinse the filter with a hose to remove loose debris as a short-term measure. For a deeper clean without a dedicated product, a diluted white vinegar soak (roughly one part vinegar to three parts water) can help break down mineral scale. Rinse thoroughly before refitting. Avoid washing-up liquid in large quantities — it leaves residue that causes foaming.
Can I soak my hot tub filter overnight?
Yes, soaking a hot tub filter overnight in a dedicated filter cleaning solution is one of the most effective deep-clean methods. Most filter cleaners are safe for an overnight soak — check your product instructions to confirm. If you're using a household alternative like diluted vinegar, six to eight hours is typically sufficient.
What's the best hot tub filter cleaner to use?
The best option is a cleaner specifically formulated for hot tub or spa filter cartridges. These are designed to dissolve oils and deposits without damaging filter fibres or leaving behind foam-causing residue. Avoid general household cleaners, bleach, or laundry detergents — they can degrade the filter material and cause water quality issues.
How often should I clean my hot tub filter?
As a general guide: rinse weekly or fortnightly, deep clean monthly, and replace the filter every 12 to 24 months. These intervals vary depending on how frequently you use your tub, how many people use it, and what environmental factors (leaves, pollen, outdoor debris) are in play.
Why is my hot tub water still cloudy after cleaning the filter?
Cloudy water after a filter clean usually points to one of a few things: the filter wasn't rinsed thoroughly enough after soaking (leaving residue), the water chemistry is out of balance, or the filter itself is past its useful life and needs replacing. Check your pH, alkalinity, and sanitiser levels before anything else.
How do I know when to replace my hot tub filter rather than clean it?
Replace the filter when pleats remain discoloured after a thorough soak, when you notice physical damage (tears, flattened folds, cracked end caps), or when water quality won't improve even with balanced chemicals. If the filter is over two years old and showing any of these signs, replacement is almost always the better call.
Keep the ritual, lose the faff
Hot tub maintenance doesn't have to be a chore. Build a quick filter rinse into your routine, schedule a monthly soak, and you'll spend far less time troubleshooting and far more time actually enjoying your tub.
If you're thinking about upgrading your setup — or you're looking for a wood-fired hot tub that's built to last and feels genuinely connected to the outdoors — take a look at our wood-fired hot tub collection and find the right fit for your space.