Short answer: drain & refill your hot tub every 3–4 months (more often with heavy use). Flush lines, power off, drain via valve or submersible pump, clean shell & filters, then refill through the filter housing with cold water to avoid airlocks.
As a hot tub owner, caring for your hot tub is essential, and emptying and refilling play a key part in maintenance. Wondering how often to do it — and the safest way?
Below, we explain why to drain/refill, signs it’s time, a step-by-step draining method (valve vs submersible pump), and how to refill properly to prevent airlocks.
Why do I need to drain and refill my hot tub?
To keep water safe and clear, you’ll need to empty the tub, clean the shell, valves, and pipework, and refill with fresh water — whether you use chlorine or bromine.
Signs it’s time:
- pH balance is hard to maintain or chemical use is increasing
- off-colour water or stronger odour
- buildup around the shell or debris in the water
How to drain a hot tub
Follow this step-by-step for a smooth, safe drain:
1) Flush out the pipes
- Remove filters.
- Add a line flush cleaner (check your manual for compatibility).
- Run jets on full for ~60 minutes with the cover off to circulate cleaner.
2) Choose your drain method
Drain valve
- Power off at the circuit breaker.
- Find the valve near the base; twist cap to remove plug.
- Attach a hose and run to an existing drain.
- If you have two valves (primary & auxiliary), use the primary first, then the auxiliary to empty internal lines.
Submersible pump
- After flushing, power off.
- Place pump at the deepest point; run hose to a drain.
- Use a wet vac to remove water remaining in the footwell.
- Rinse shell thoroughly to remove residue.
How to fill a hot tub (without airlocks)
1) Refill through the filter housing
Don’t leave the hose in the shell. Feed the hose through the filter housing so water fills the pipework first — this prevents airlocks.
2) Avoid hot water
Use cold water only. Hot water can damage temperature sensors and doesn’t meaningfully speed things up.
3) Don’t overfill or underfill
Fill to around halfway up the filter cage. Low water draws air into plumbing (flow/heat issues); frequent drops may indicate a leak.
Recommended drain/refill schedule
| Usage | Drain & refill | Notes |
|---|---|---|
| 1–2 times/week | Every 4–6 months | Test chemistry weekly; rinse filters weekly |
| 3–5 times/week | Every 3–4 months | Add quarterly line flush + filter soak |
| Daily / heavy use | Every 1–2 months | Consider dual filter sets to rotate |
Shop essentials
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Now you know how to keep your water in great shape — whether it’s summer maintenance or prepping for colder months. Dive deeper into hot tub water chemistry and winter prep.
Need the right kit for a perfect refill?
Grab line flush, replacement filters, and a high-quality cover — or ask our team to match parts to your model.
Hot tub draining FAQs
Can you drain a hot tub onto grass?
How often should you drain a hot tub?
Is it safe to leave a hot tub empty?
Why isn’t my hot tub draining?
Get line flush & the right filter for your model.
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