How to Clean a Hot Tub: The Complete Guide to Consistently Clean Spa Water

A hot tub is meant to be your at-home wellness fix — but only if the water actually stays clean and hygienic. Most owners focus on chlorine, pH and rinsing the filter. A really effective hot tub clean covers more ground than that.

To keep the water clear and stop build-up forming inside the system, you need to clean the water, the filter and the pipework on a regular basis. This guide walks through how to do that properly so the water quality stays good long term.

The three key areas of hot tub cleaning

1. The water

Spa water should be tested regularly, with the key readings kept in range:

• pH
• Chlorine level
• Total alkalinity

Unbalanced water can lead to cloudiness, skin irritation or scale build-up.

2. The filter

The filter pulls particles out of the water and needs cleaning on a steady schedule:

• Rinse the filter every 1–2 weeks
• Give it a thorough deep clean monthly
• Replace it roughly every 12 months depending on use

A clean filter keeps the spa running efficiently and the water clear. For replacement intervals by filter type, see how often to change a hot tub filter.

3. The pipework

The most important — and most overlooked — part of cleaning a hot tub is the pipework inside the system. Over time, residues build up in there:

• Body oils
• Lotions and cosmetic residue
• Skin particles
• Soap residue

These deposits can form a slimy layer known as biofilm. Biofilm builds up where bacteria and other microorganisms settle in damp environments and stick to the inside of the pipework. It can lead to:

• Water that turns cloudy faster
• More foaming
• Off-smells
• Chemicals working less effectively

Why pipework cleaning matters

Even with regular water changes, residues can stay behind in the plumbing. When you refill the spa, that build-up can recontaminate the fresh water almost straight away. That's why most manufacturers recommend cleaning the pipework whenever you do a water change.

For this you need a dedicated hot tub pipework cleaner. Canadian Spa Spa Flush Plumbing and Jet Cleanse is one example — designed to lift oils, lotions, cosmetic residue and biofilm out of the system.

The cleaner is added to the existing spa water and circulates through the entire pipework, lifting deposits out of the jets, lines and shell.

Step by step: cleaning your hot tub properly

A thorough clean should happen on a regular basis, especially at every water change.

1. Remove the filter. Take the filter cartridge out before you start.
2. Clean the pipework. Add a pipework cleaner like Spa Flush to the existing water. It circulates through the lines and shifts deposits and biofilm.
3. Run the jets. Switch on all pumps and jets and open the air valves fully so the cleaner is pushed right through the pipework.
4. Let it circulate. Run the jets for 15 to 30 minutes. You may see foam or dark residue appear in the water — that's normal and means it's working.
5. Drain the spa. Empty the water completely afterwards.
6. Wipe down the shell. Give the inside surface a quick wipe to lift any remaining residue.
7. Refill. Fill the tub with fresh water and rebalance the water chemistry.

How often should you clean a hot tub?

For consistently good water quality, the following routine works well:

Task	Frequency
Test the water	2–3 times a week
Rinse the filter	Every 1–2 weeks
Deep clean the filter	Monthly
Change the water	Every 3–4 months
Clean the pipework	At every water change

Many specialists also suggest flushing the pipework with a dedicated cleaner roughly every 4–6 months to keep biofilm under control.

The full deep clean at a water change

The pipework flush above is the first half of a proper deep clean. The second half happens once the spa is empty, and it is the best chance you get to clean the parts you cannot reach when the tub is full. Allow a morning for the whole job, plus heating time afterwards.

1. Switch off the power. Turn the spa off at the isolator, or unplug a 13 amp plug-and-play model, before you drain. Pumps and heaters must never run without water.
2. Drain through the drain valve. Unscrew the cap, fit a garden hose, then push the valve in and twist to let the water run. Send it to the foul drain rather than onto a lawn or borders. Our guide to operating your drain valve covers this in detail. A submersible clean water pump speeds things up and clears the last few centimetres from the footwell.
3. Clean the filter housing. With the cartridge out, rinse grit, hair and leaves out of the housing and basket. Debris left here goes straight back into the clean water.
4. Clean the shell. Wipe the acrylic with a soft cloth and a cleaner made for spa surfaces, paying attention to the waterline, the footwell and around the jets. Avoid washing-up liquid and household sprays, as the residue causes foaming once you refill.
5. Rinse out the residue. Rinse the shell with clean water and let the rinse water drain away before you close the valve.
6. Swap in a clean filter. Fit your spare cartridge, or a cleaned and fully dried one. A wet cartridge fresh from a soak restricts the flow.
7. Refill through the filter housing. Close the drain valve, then put the hose into the filter housing and fill. This pushes water through the pump first and helps prevent an airlock. Fill to about 25mm above the waterline on the shell. Our filling guide walks through the full start-up.
8. Rebalance in the right order. Power on, let the water circulate, then set total alkalinity first, pH second and sanitiser last. Re-test before anyone gets in.

What each cleaning job involves

The frequency table above tells you when. This one tells you what to use and what you are aiming for, so nothing gets skipped.

Job	What you need	What good looks like
Test the water	Test strips	pH 7.2 to 7.6, total alkalinity 80 to 120 ppm, sanitiser in range for your system
Skim the surface	Leaf skimmer net	No leaves, insects or floating debris left to sink and break down
Rinse the filter	Garden hose, or a filter cleaning brush	Pleats open and free of loose dirt
Deep clean the filter	Filter cleaner and a bucket	Overnight soak, rinsed and fully dried before refitting
Shock the water	Non-chlorine spa shock	Fresh smell, no dullness after heavy use
Vacuum the floor	Spa vacuum	No sand or grit in the footwell or seat corners
Flush the pipework	Spa Flush or Whirlpool Rinse	No dark residue or foam appearing when the jets start
Clean the cover	Mild soap, clean water, vinyl conditioner	Top and underside clean, no mould on the underside

Habits that keep the water cleaner for longer

Most of the dirt in a hot tub arrives on the people using it. A few habits cut the load on your filter and sanitiser, which means fewer problems between water changes.

• Shower before you get in. Washing off deodorant, moisturiser, sun cream and hair products stops them coating the pipework and feeding foam.
• Keep the cover on between soaks. It keeps leaves, pollen and insects out as well as holding the heat in.
• Rinse swimwear in plain water. Detergent left in fabric is one of the most common causes of foaming.
• Add an oil absorber. A Spa Ball sits in the filter box and soaks up oils from the water surface before they reach the cartridge.
• Dose little and often. Small regular doses of sanitiser keep levels stable. Large occasional doses swing the readings and can bleach the underside of the cover.
• Test after a busy session. Several bathers in one evening use up sanitiser quickly, so check the next day rather than waiting for the usual test.

Cleaning the cover

A dirty cover undoes a clean hot tub, because whatever grows on the underside drips back into the water. Wash the top and the underside with mild soap and rinse with clean water as often as needed. Never use a pressure washer, solvents, abrasive cleaners or products containing silicone or alcohol, as they damage the vinyl. When you shock the water, take the cover off completely and leave it open for 30 minutes so the fumes do not bleach the underside. Our guide to caring for your hot tub cover covers vinyl care in more detail.

Hot tub cleaning FAQ

Can I use household cleaning products on my hot tub?

No. Washing-up liquid, bathroom sprays and general cleaners leave residues that cause foaming and upset the water balance. Use products made for spas, and rinse the shell with clean water before you refill.

Why does my water go cloudy soon after a refill?

The usual causes are biofilm left in the pipework, a dirty filter or water that has not been balanced. Flush the pipework before you drain, fit a clean filter and set alkalinity, then pH, then sanitiser. If it persists, our cloudy, foamy and green water guide takes you through the fixes.

How long does a full deep clean take?

The pipework flush takes 15 to 30 minutes of jet time. Draining takes a few hours for a typical home spa holding 800 to 1,400 litres, and refilling takes a similar time. Allow extra time for the water to heat back up before you use it.

Do I need to clean the hot tub if the water looks clear?

Yes. Clear water can still carry biofilm in the pipework and a filter that is close to blocking. Stick to the schedule rather than waiting for a visible problem.

What is the difference between Spa Flush and Whirlpool Rinse?

Both clean the plumbing before a water change. Spa Flush is a gel formula designed to break through biofilm and fatty deposits so water pressure can push them out. Whirlpool Rinse is designed to remove soap and oil deposits from the pipes and hoses. Pick one and use it at every water change.

If you would like help choosing the right products for your spa, call us on 01293 824094 or browse our hot tub chemicals range.

Wrapping up

A clean hot tub is more than clear water. For solid hygiene, the water, filter and pipework all need to be looked after on a regular basis. The pipework in particular is often underestimated. Products like Canadian Spa Spa Flush help shift biofilm, oils and other build-up out of the lines and improve water quality long term.

Available on our UK website:

• Canadian Spa Spa Flush — view product

With a proper routine, your hot tub stays hygienic, the water stays clear, and ongoing care becomes a lot less painful.