Hot tub maintenance, the part nobody mentions at the showroom

What is hot tub maintenance?

Hot tub maintenance is the continuing routine that keeps spa water safe and the equipment healthy: testing and adjusting water chemistry, cleaning and rotating filters, draining and refilling on a schedule, and preparing the spa for winter. Unlike most home services it is mostly not something you hire out - the weekly water work is the owner's job and it does not stop. A service plan handles the periodic and technical parts around it.

Signs you need hot tub maintenance

• The water has gone cloudy, foamy, or has developed a smell
• Nobody has tested the water in longer than a fortnight
• The filters have never been taken out, or have been rinsed but never properly cleaned
• You have noticed a slippery film on the shell or waterline, or scale building at the water line
• Heating is taking longer than it used to, or the running cost has crept up without the weather changing
• You are approaching your first winter with the spa and have no plan for it
• You inherited the spa with the house and have no idea when it was last drained
• You are away for stretches and there is nobody to look after it while you are gone

Seeing something not on this list? Browse hot tubs & spas problems by symptom →

How hot tub maintenance actually works

1. 1

   Test the water, then adjust - in that order

   The routine is test first, act on the reading, retest. Sanitiser level, pH and alkalinity are the core, with hardness and any stabiliser depending on your system and your fill water. Adjusting blind is how people chase their own tail for weeks.

   Watch forAdding sanitiser to fix cloudy water without checking pH. Sanitiser effectiveness depends heavily on pH being in range, so out-of-range water can be full of chemical and still not sanitised. Fix the balance and the sanitiser starts working.

2. 2

   Look after the filters properly

   Filters need regular rinsing, periodic deep cleaning with a proper filter cleaner rather than a hose alone, and eventual replacement. Owning a second set so one can be cleaning and drying while the other works is the single most practical habit in spa ownership.

   Watch forA hose rinse being treated as a clean. Rinsing removes surface debris; it does not touch the oils and lotions that clog the media and choke flow - and choked flow is behind a large share of "my spa will not heat" calls.

3. 3

   Drain and refill on a schedule

   Spa water accumulates dissolved solids that no amount of chemical will remove, and eventually the only fix is fresh water. The right interval depends on how heavily the spa is used relative to its volume, and the manufacturer will give guidance.

   Watch forWater that has become steadily harder to balance despite correct dosing. That is usually the signal you are past due for a refill rather than a chemistry problem to solve.

4. 4

   Purge the plumbing when you refill

   Biofilm builds inside the pipework where you cannot see it and it survives normal sanitiser levels. A purge product run through the system before draining clears it, and refill day is the only convenient moment to do it.

   Watch forFoam or a persistent smell that returns days after a fresh fill. That usually means the plumbing was never purged and the new water is being recontaminated from inside the pipes.

5. 5

   Clean the shell and the cover underside

   With the spa empty, the shell gets cleaned with a spa-safe product, and the underside of the cover - which sits in warm vapour permanently - gets cleaned and inspected. The cover is a part of the system, not an accessory.

   Watch forHousehold cleaners on the shell. Residue foams badly on refill and some products attack acrylic. Also check the cover for water weight while it is off - see cover replacement.

6. 6

   Winterise, or commit to running through

   There are two valid cold-climate strategies and one disastrous one. Keep it running and heated all winter, with the freeze protection working and the cover in good condition. Or shut it down properly - fully drained, plumbing and pumps cleared of water, blown through, and covered. The disastrous option is leaving it full and switching it off.

   Watch forA partial drain. Water left in pumps, heater and low points is exactly what splits when it freezes, and freeze damage typically appears at several points at once. If you are shutting down for winter, have it done thoroughly or have someone do it.

What does hot tub maintenance cost?

Two ongoing costs, and the second surprises people. Chemicals, filters and test kits are modest and predictable. Electricity to hold a spa at temperature is the larger figure and it is permanent, driven by climate, insulation and cover condition. Service plans are typically priced per visit or as a seasonal package.

See the full hot tub maintenance cost guide - by material, size and region →

If the number is the problem, here are the ways people pay for it →