Hot tub maintenance schedule
Test and top up sanitizer at every soak, shock and rinse the filter weekly, deep-clean the filter monthly, and drain and refill every 3–4 months (the Pool & Hot Tub Alliance schedule). For a 400-gallon tub, the after-soak top-up is usually small: about 5.4 g (0.2 oz) of 56% dichlor for +2 ppm chlorine.
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 (8 sections)
After every soak
A hot tub holds a few hundred gallons of hot water shared by several people, so it changes faster than a pool. After each use:
- Test sanitizer. Bring free chlorine (FC) back to 3–4 ppm (or up to your label's limit), or check that bromine is 4–6 ppm. The CDC advises testing chlorine and pH at least twice a day when a pool or hot tub is being used, more often with more people. If you soak daily, a quick strip test before and after is a good habit. Amounts by tub size are on the chlorine dosing page.
- Leave the cover open with the jets running for about 30 minutes after adding chemicals, then close and lock it.
- Glance at the water. Haze, foam, or a strong smell are early signs. Deal with them before they get worse.
- Remove the floater before getting in, if you use bromine tablets.
Not using the tub? Test two or three times a week anyway: sanitizer still drops slowly in hot water.
Weekly
- Full test: sanitizer, pH, and total alkalinity (TA). Correct alkalinity first, then pH.
- Shock. Use MPS (non-chlorine shock) in a routine week. Use chlorine shock if the water is cloudy, smells, or had heavy use. See shocking a hot tub for amounts and waiting times.
- Rinse the filter with a garden hose, pleat by pleat (PHTA recommends a weekly rinse). A spare filter makes this easy: swap it in, and let the other one dry.
- Wipe the waterline with a soft cloth to remove the oily ring before it hardens.
- Check the water level. Top up if it is near the lowest jets or the skimmer is sucking air.
Monthly
- Deep-clean the filter by soaking it in a filter cleaning solution (PHTA: monthly), then rinse well. Oils and lotions need a cleaner; water alone won't lift them.
- Test calcium hardness, and total dissolved solids (TDS) if you have a meter. Target calcium is 150–250 ppm.
- Clean the cover: wipe both sides, check the underside for mildew and the seams for tears. A waterlogged cover loses heat and is heavy to lift.
- Look at the equipment bay for drips or corrosion, and clear leaves from vents.
- Check your supplies for age: liquid chlorine and bleach lose strength in storage, especially when warm.
Every 3–4 months: drain and refill
PHTA's consumer guide says to drain and refill every 3–4 months, or as your manufacturer recommends. The real interval depends on how much the tub is used: heavy daily use shortens it, and occasional use lengthens it. A widely repeated rule of thumb (gallons ÷ 3 ÷ soakers per day) gives about 67 days for a 400-gallon tub with two soakers a day. We could not confirm the rule's original source. The water change calculator runs it for your tub.
Drain sooner if the water stays cloudy or keeps foaming after a shock and a clean filter. The refill routine:
- With the old water still in, run a spa line cleaner if the label calls for it (it lifts biofilm from the plumbing).
- Turn off power at the breaker, then drain.
- Clean the shell with a non-foaming spa surface cleaner and rinse it well.
- Clean or replace the filter. PHTA suggests replacing the cartridge every 12–18 months, or as needed.
- Refill through the filter well, restore power, and follow the first-fill start-up steps.
Winter tips
- Keep it running. A running, heated tub is much safer in freezing weather than one that is turned off. If power fails in a freeze, the plumbing is at risk: check your manual for what to do, and have a plan before winter starts.
- If you shut it down, drain completely and blow out the lines as your manufacturer describes. Any trapped water can freeze and crack pipes.
- Keep the cover sealed. Brush off heavy snow, and check that straps are locked. Wind can get under a loose cover.
- Chemistry slows with less use, but sanitizer still drops in hot water. Keep testing on a schedule.
- Watch the temperature. Keep it at 104 °F or lower (CPSC), even on cold nights.
- Holiday guests mean heavy use: shock afterward and check the filter.
Printable schedule
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| When | Task |
|---|---|
| Every soak | Test and top up sanitizer (FC 3–4 or Br 4–6 ppm); cover open 30 min after dosing |
| 2–3 × a week when idle | Test sanitizer and pH |
| Weekly | Test TA and pH; shock; rinse filter; wipe waterline; check water level |
| Monthly | Soak filter in cleaner; test calcium (150–250 ppm); clean cover; check equipment |
| Every 3–4 months | Line cleaner, drain, clean shell, clean or replace filter, refill, start-up |
| Every 12–18 months | Replace filter cartridge (or as needed) |
| Yearly | Consider a professional inspection (PHTA) |
Back to the hot tub care hub for all topics.
Safety
- Turn off power at the breaker before draining or working on equipment.
- Never mix chemicals or cleaners with each other. Add each to the water separately.
- Keep the cover locked when the tub is not in use. A locked cover helps keep children out of the water.
- If someone swallows spa chemicals or gets them in their eyes, call Poison Control at 1-800-222-1222.
- Always follow the product label. It is a violation of federal law to use a pesticide product in a manner inconsistent with its labeling.
FAQ
How often should I shock my hot tub?
Weekly as a routine, and after heavy use such as a party or a long soak with several people. Shock sooner if combined chlorine is 0.5 ppm or more, the water smells of chlorine, or it turns cloudy.
How often should you clean a hot tub filter?
Rinse it with a hose weekly and soak it in a filter cleaner monthly, as PHTA recommends. Replace the cartridge every 12–18 months, or sooner if the fabric is torn or it no longer comes clean.
How often should I change hot tub water?
Every 3–4 months, or as your tub's manufacturer recommends (PHTA). Heavy use means sooner. Drain early if foam or cloudiness returns quickly after shocking.
Sources
- Pool & Hot Tub Alliance (PHTA), Maintaining your hot tub (drain every 3–4 months, weekly rinse, monthly filter soak, replace every 12–18 months, annual inspection): phta.org
- CDC, Home pool and hot tub water treatment and testing (testing frequency): cdc.gov
- U.S. Consumer Product Safety Commission, hot tub temperatures: cpsc.gov
- PHTA fact sheet, Sodium hypochlorite (strength loss in storage): phta.org