How often to change hot tub water
How often to change hot tub water: take the gallons, divide by 3, then divide by daily users to get the days. With 3 daily users, a 300 gallon (1,140 litre) tub requires fresh water about every 33 days.
To see when to change the water, pick your tub and tell us how many people use it.
- Days between draining and refilling
- Divide gallons by 3, then divide by users
- Maximum time when using chlorine or bromine
- 3 to 4 months
- When to drain and refill based on dissolved solids
- 1,500 ppm
- Use a hose to rinse the filter
- Weekly
How often to change hot tub water: the formula
Jacuzzi follows a simple rule. Take the gallon capacity of your tub and divide it by 3. Next, divide that result by the average number of daily users. This result shows how many days pass between water changes.
With 3 daily users in a 300 gallon (1,140 litre) tub, calculate 300 ÷ 3 ÷ 3 to get about 33 days. Since more bathers add more sweat, soap and lotion, the water wears out faster.
No matter what the math shows, stop at 3 to 4 months for chlorine or bromine. Both Hot Spring and Jacuzzi state this as the standard rule. Hot Spring notes its salt system can extend this to a year.
Days between water changes for each tub size
| Tub | 1 person | 2 people | 3 people | 4 people | 6 people |
|---|---|---|---|---|---|
| Inflatable, 180 gal (670 L) | 60 days | 30 days | 20 days | 15 days | 10 days |
| Hard tub, 250 gal (930 L) | 83 days | 42 days | 28 days | 21 days | 14 days |
| Inflatable, 290 gal (1,100 L) | 97 days | 48 days | 32 days | 24 days | 16 days |
| Hard tub, 350 gal (1,330 L) | 117 days | 58 days | 39 days | 29 days | 19 days |
| Hard tub, 500 gal (1,900 L) | 120 days (the cap) | 83 days | 56 days | 42 days | 28 days |
If your calculation exceeds about 120 days, follow the 3 to 4 month limit instead. Inflatable models often require earlier changes: Intex advises every 2 to 3 months, while Bestway recommends every 1 to 3 months.
Signs it is time for a hot tub water change
- Foam that returns after you treat it. Jacuzzi treats heavy foam or murky water as the sign to drain and refill. Learn more about hot tub foam.
- Water staying cloudy despite treatment. Jacuzzi states the buildup exceeds what chemicals can handle. Read about cloudy hot tub water.
- A smell that's unpleasant. Jacuzzi ties this smell to bacteria or organic matter that breaks down in the water.
- When dissolved solids go above 1,500 ppm. It is time to drain, says Jacuzzi, when TDS, the total dissolved solids, goes past that mark.
- Your skin feels unclean. Built-up soap causes this feeling, and no chemical fixes it, per the Hot Spring manual.
At that point, use the guide for how to drain a hot tub. Next, allow for the heat-up time before soaking again.
Schedule for hot tub maintenance
Draining and refilling is the major task. Minor tasks keep the water fine until then.
| Job | How often | Who says so |
|---|---|---|
| Test chlorine and pH | Twice a day when in use | CDC |
| Test alkalinity | Weekly | Hot Spring manual |
| Shock | Weekly, and after a busy soak | Hot Spring manual |
| Use a hose to rinse the filter | Weekly | Jacuzzi |
| Soak the filter in cleaner | Monthly | Jacuzzi |
| Deep soak the filter | Every 3 to 4 months | Jacuzzi |
| Drain and refill | Use the date from the tool, capped at 3 to 4 months. | Hot Spring |
How often to clean hot tub filter cartridges
Jacuzzi's filter guide outlines a three-step process. Hot Spring recommends cleaning at least once a month. American Whirlpool advises doing it every two weeks for strong jets.
| Job | How often | How |
|---|---|---|
| Hose rinse | Weekly | Use a garden hose to spray between the pleats, then allow it to dry. |
| Chemical clean | Monthly | Apply filter cleaner, then rinse with warm water until gone. |
| Deep soak | Every 3 to 4 months | Soak in filter cleaner for 12 to 24 hours, then rinse well. |
Avoid dish soap, laundry detergent, bleach, and dishwashers entirely. Jacuzzi warns that soap trapped in fibers causes foaming each time the tub runs.
How often to change hot tub filter cartridges
Jacuzzi recommends replacing filters about once a year, or sooner if they crack, tear, or remain dirty. A well-maintained cartridge can last 12 to 24 months. Poor care might require replacement every 6 months.
Jacuzzi also recommends buying two filters to rotate them. Both last longer when one dries out and the other remains in the tub.
Settings for the hot tub filtration cycle
Each day, a timer starts the pump so water passes through the filter; that timer is the filtration cycle. According to the American Whirlpool manual, it comes in two steps. Each pump purges the pipes by running for one minute first. Next, pump 1 runs at low speed to clean the water.
Pushing a pump button pauses the cycle. It restarts 40 minutes after the last button press. To save energy, the manual suggests running cycles at night or during cooler hours.
Common questions
How often should the water in a hot tub be changed?
Hot Spring and Jacuzzi say most tubs on chlorine or bromine need changes every 3 to 4 months. Heavily used tubs require earlier changes: get the days by dividing gallons by 3, then by daily users.
What is the water change schedule for an inflatable hot tub?
Bestway recommends every 1 to 3 months, while Intex suggests every 2 to 3 months. If the water gets foamy or cloudy, change it earlier.
How often should a hot tub filter be replaced?
Jacuzzi says about once a year. Good care lets a cartridge last 12 to 24 months, but poor care means about 6 months. Cracks or tears mean you should replace it sooner.
At what TDS level should you drain a hot tub?
Once total dissolved solids go over 1,500 ppm, Jacuzzi says drain and refill. High TDS makes sanitizer perform worse and can cause scale and corrosion.
How long can you keep water in a salt water hot tub?
With its salt system, Hot Spring says spa water can last up to a year. It states 3 to 4 months for chlorine or bromine.