Domakihub How to Winterize a Hot Tub and Protect It Off-Season
A complete shutdown checklist to prevent freeze damage and keep your spa ready for next season.
Reviewed by Domakihub pool pros · 2026-06-23 · 5 min read
If you own a hot tub at a villa, holiday rental, or hotel in Greece and plan to shut it down for the colder months, a proper winterization is the single step that separates a spa that reopens smoothly in spring from one that arrives with cracked pipes and a hefty repair bill. The video above walks through the full process visually; this guide pairs it with an ordered checklist and the answers to the questions owners ask most. Greece winters are mild compared to northern Europe, but overnight frost in mountain areas and on many islands is enough to split an unprotected plumbing line.
Why Winterizing Matters Even in Greece
Most hot tub damage caused by cold happens not during sustained freezes but during a single hard overnight frost when residual water sitting in jets, blowers, and filter housings expands as it turns to ice. In regions like the Peloponnese highlands, Epirus, or inland Crete this can happen as early as November. A winterization drains and air-purges every water-holding component so there is nothing left to freeze.
Rental property owners face an additional risk: a tub left full but unheated during a vacancy period is also a bacteria breeding ground. Draining and drying the shell correctly means you return to a clean, odour-free spa rather than a green one.
What You Will Need Before You Start
Gather your tools in advance so the job moves without interruption: a submersible pump or the tub's built-in drain valve, a wet-dry shop vacuum, non-toxic RV or spa antifreeze (propylene glycol — never ethylene glycol, which is toxic), a fresh filter cartridge or a bucket for soaking the existing one in filter cleaner, and a waterproof cover with tight-fitting buckle straps.
You will also want a bottle of spa flush or line cleaner, a non-abrasive surface cleaner for the acrylic shell, and clean dry towels. Block out two to three hours for the first time you do this; experienced owners typically finish in under ninety minutes.
How to Winterize Your Hot Tub: 5 Key Steps
- 1
Flush the Lines and Balance the Water
Two to three days before the full shutdown, add a line-flush product through the filter compartment and run all jets for fifteen to thirty minutes. This dissolves biofilm that accumulates inside the plumbing over the season. On the final day, test the water and bring pH, alkalinity, and sanitizer into normal range — this protects the shell and jets from staining or corrosion while they sit dry.
- 2
Drain the Tub Completely
Open the main drain valve (usually located behind an access panel near the base) or drop a submersible pump into the footwell. Direct the hose away from foundations, driveways, or drainage channels that could flood. Once the water level drops too low for the pump, remove the filter cartridges and drain those housing chambers as well. Most tubs hold 1,000 to 2,000 litres, so budget enough discharge time and check local wastewater rules if you are near a sensitive area.
- 3
Blow Out Every Jet and Water Line
This is the step most owners skip and later regret. Set your shop vacuum to blow (not suction) and press the nozzle firmly over each jet opening in turn, holding it for five to ten seconds. Work around every seat position. Then blow through the filter housing inlet, the blower outlet, and any auxiliary water features. You will see water spit out into the empty shell — mop it out and repeat until each jet produces only air. This eliminates the residual water that would otherwise freeze.
- 4
Add Antifreeze and Protect the Equipment Bay
Pour a litre of non-toxic spa antifreeze into each filter housing and down the main drain line. This acts as insurance against any water you may have missed. Open the equipment bay and inspect the heater, pump unions, and any valves: leave unions slightly loose so any expansion has somewhere to go rather than cracking a fitting. If your area regularly sees sustained sub-zero temperatures, wrap the equipment bay in pipe-insulation foam as an extra precaution.
- 5
Clean, Dry, and Cover the Shell
Wipe down the entire acrylic interior with a non-abrasive spa cleaner and dry it thoroughly with clean towels — mould cannot grow on a dry surface. Clean the filter cartridge in filter-cleaner solution, rinse it well, and store it indoors in a cool dry place rather than leaving it in the spa. Set the cover in place and fasten all buckle straps securely. A well-fitted cover also insulates the interior slightly, adds a second line of defence against frost, and keeps debris out so spring reopening is quick.
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FAQ
- Do I need to winterize my hot tub if I live in a warm part of Greece?
- In coastal areas below 200 m altitude — central Athens, Thessaloniki's coast, most of the Cyclades — sustained freezing is rare, but a single overnight frost is still possible in January or February. If you plan to leave the tub unused and unheated for more than two weeks in winter, a full winterization is the safest option. If you keep it running and heated all year, no winterization is needed.
- Can I just leave antifreeze in the tub instead of draining it?
- No. Antifreeze is added only to residual water in the lines and housings after draining, not to a full tub as a substitute for draining. Filling or partially filling a tub with antifreeze is expensive, harmful to jets and seals over time, and environmentally problematic when you discharge it. Always drain first.
- How do I reopen the hot tub in spring?
- Reinstall the cleaned filter cartridge, close all drain valves and tighten any union fittings you had loosened, then fill the tub via the filter housing to avoid air locks. Once full, restore power, set the thermostat to your usual temperature, and let the system run a full heating cycle. Add a start-up dose of sanitizer and balancing chemicals, test the water after 24 hours, and the spa is ready to use.