How to Clean a Hot Tub Filter (and How Often)
Rinse the cartridge with a garden hose every week, soak it in a spa filter cleaner every 4 to 6 weeks, and replace it every 12 to 18 months. Intervals differ by maker, so your owner's manual wins; the table below shows what four sources say.
Always follow your product’s label directions. Pool and spa chlorine, bromine, shock and algaecides are EPA-registered pesticides: use products labeled for pool or spa use, and don’t swim or soak until levels are within the limit on your product’s label. If this page and a label disagree, the label wins.
On this page (9 sections)
What the filter does
The cartridge is a pleated fabric tube in the filter bay of your tub. It catches dirt, hair, and body oils as water passes through. A clogged cartridge slows the flow, which weakens the jets and the heater, and leaves less clean water to circulate through the sanitizer. Sundance lists water that stays cloudy even when the chemistry is right as a sign that a filter needs replacing.
Filter care also affects safety. The CDC says that replacing the hot tub filter on the manufacturer's schedule is an important step in preventing Legionella growth. It also says to replace the filter whenever a tub is drained and disinfected after a contamination problem.
How often: what four sources say
| Source | Rinse with hose | Chemical clean or soak | Replace |
|---|---|---|---|
| PHTA (industry association) | Weekly | Monthly, in a filter cleaning solution | Every 12–18 months, or as needed |
| Jacuzzi | Weekly | Monthly: cleaner on for 15–20 minutes. Quarterly: soak 12–24 hours | About once a year in normal use |
| Sundance | Weekly | Every 4–6 weeks: soak overnight (8–12 hours) | 12–18 months standard use; 6–12 months heavy use; up to 24 months light use |
| Bullfrog Spas | Every 3–6 weeks (round filters) or every 4 weeks (flat filters) | Soak when needed for oils or calcium | Round filters: 1–2 years. Flat filters: every 12–16 weeks |
The table is our summary of each maker's published schedule. We found no single standard, and the makers do not agree, so treat these as ranges. Sundance is the only source that ties replacement to how hard the tub is used: heavy use means the shorter end. For your own tub, the plain rule is to start from your manual's numbers and shorten them if you soak often or have many bathers. That rule is our suggestion, not a published figure.
Weekly rinse, step by step
- Turn the tub's power off at the control panel or breaker.
- Lift the filter out of its bay. Most twist a quarter turn or lift straight up.
- Hold it over a drain or a lawn, not over the tub. Spray with a garden hose and a straight nozzle, working between each pleat from top to bottom. Jacuzzi says to use moderate pressure.
- Turn the filter and repeat until the water runs clear from every pleat.
- Look for cracks, tears, frayed edges, or flattened pleats. Jacuzzi lists these as reasons to replace the filter.
- Put it back and restore power.
Never use a pressure washer or a wire or stiff brush. Sundance and Bullfrog both warn that these damage the filter material.
Soak clean, step by step
Hose rinsing removes dirt but not oils. Lotions, sunscreen, and body oils coat the pleats, and only a spa filter cleaner dissolves them. Use a product made for spa filters and follow its label for the mix and the soak time.
- Rinse the filter with a hose first, as above.
- Mix the cleaner with water in a bucket or a filter-soak tube, in the ratio on the label. Jacuzzi mentions typical ratios of 1 part cleaner to 5 to 10 parts water, but use the ratio on your product's label.
- Stand the filter in the solution so it is fully covered. Soak for the time on the label. Makers' times range from 15–20 minutes for a monthly clean to overnight or 12–24 hours for a deep soak.
- Rinse the filter thoroughly with a hose. Leftover cleaner makes foam in the tub. See foamy hot tub.
- Let it dry if you can, then reinstall. A dry filter is easier to inspect for wear.
Safety. Wear gloves and eye protection when handling filter cleaner. Do not mix cleaners with chlorine, bromine, or each other. Keep the soak solution away from the tub water. Always follow the product label. It is a violation of federal law to use a pesticide product in a manner inconsistent with its labeling. Poison Control: 1-800-222-1222.
Some makers cover calcium deposits. Bullfrog describes soaking in a muriatic acid solution (1 part acid to 10 parts water) for calcium, while Sundance's list of things to avoid includes household acids. Because the makers disagree, we do not recommend acid unless your own manual says to use it.
What not to use
| Method | Why | Source |
|---|---|---|
| Pressure washer | Damages pleats | Sundance |
| Dishwasher | Heat can melt parts; detergent can damage the glue | Jacuzzi, Sundance |
| Bleach or harsh chemicals | Destroy filter fibers and can void a warranty | Jacuzzi, Sundance |
| Household cleaners and laundry detergent | Leave residue that causes foam | Jacuzzi, Sundance |
| Wire or stiff brushes | Damage the media | Sundance; Bullfrog warns brushes can damage it |
The two-filter rotation
Buy a second cartridge of the same model. Keep one in the tub and one clean and dry on the shelf.
- At each soak clean, swap the dirty filter out and put the clean spare in.
- Clean the dirty one and let it dry completely. Jacuzzi notes that rotating between two filters lets one dry while the other works, which extends their life.
- Swap again at the next cleaning.
Rotating also means the tub is never down while you wait for a soak to finish, and it helps at a water change. Swap in the clean spare when you drain and refill. See hot tub water change.
When to replace the filter
Replace the cartridge if you see any of these, even before the interval is up:
- Cracks, tears, or frayed edges, or a cracked end cap or damaged core.
- Crushed, wavy, or matted pleats that do not spring back.
- Permanent discoloration that a soak does not remove.
- Cloudy water or weak jets that persist after a clean, with chemistry in range. Check your readings first with the hot tub chemistry chart and see cloudy or green water.
Use a replacement made for your tub's model. A different size can bypass the filter. If you are not sure which one fits, take the old cartridge to a spa dealer, or read the model number on its end cap.
Put filter care on your schedule with the full routine on the hot tub maintenance page. A dirty filter is also behind many hot tub smells.
FAQ
How often should I clean my hot tub filter?
Rinse it weekly. Soak it with spa filter cleaner every 4 to 6 weeks (Sundance) or monthly (PHTA, Jacuzzi). Follow your manual if it gives different numbers.
Can I clean a hot tub filter in the dishwasher?
No. Jacuzzi and Sundance both list the dishwasher as something to avoid, because the heat can melt parts and the detergent can damage the filter.
How long do hot tub filters last?
Most makers say 1 to 2 years. PHTA says every 12 to 18 months or as needed. Bullfrog's flat filters are replaced every 12 to 16 weeks.
Can I use bleach to clean my hot tub filter?
No. Jacuzzi and Sundance say bleach destroys filter fibers. Use a cleaner made for spa filters.
Why is my hot tub cloudy after cleaning the filter?
Leftover cleaner can foam or cloud the water, so rinse thoroughly. Also test your chemistry. If the water stays cloudy with the right readings, the filter may be worn out.
Sources
- Pool & Hot Tub Alliance (PHTA), Maintaining your hot tub (weekly rinse, monthly soak, replace every 12–18 months): phta.org
- Jacuzzi, How to clean a hot tub filter (weekly, monthly, quarterly; what to avoid; rotation): jacuzzi.com
- Sundance Spas, How to clean a hot tub filter (rinse, soak, replacement by use, what not to use): sundancespas.com
- Bullfrog Spas, How to clean, take care of, and replace a hot tub filter: bullfrogspas.com
- CDC, Controlling Legionella in hot tubs (filter replacement per manufacturer): cdc.gov