Winterizing a Pool on Mallorca: Options and Costs

A pool on Mallorca never actually freezes. Even so, every autumn brings the same question: keep the pump running or shut everything down? If you want to winterize your pool on Mallorca, you have three options, and each one costs something different. One burns electricity for a pool nobody swims in until April, another turns into a green soup by March if you handle it carelessly. Here are the three routes worked out in detail, including what happens to a saltwater chlorinator over winter and when to get started on the island.

What "winterizing" means on Mallorca, and when to start

Winterizing a pool (Spanish: invernaje or hibernación de la piscina) covers everything you do to keep a pool stable through the cold months without anyone swimming: cleaning and balancing the water, backwashing the filter, cutting run times or adding winter chemicals, covering the pool, and protecting the equipment from damage.

Back home, winterizing is all about frost. On Mallorca, the water temperature in an unheated pool drops to around 10 to 13 degrees Celsius in January, which is nowhere near freezing. The island's real problem is the mild winter itself: at 15 degrees, algae grow slowly, but they grow. A pool you switch off in November and don't look at again until March will be green by spring. On top of that, there are leaves, Sahara dust, and rain that shifts the pH.

The rule of thumb among pool companies is to winterize once the water stays permanently below 15 degrees. Starting earlier wastes chemicals, since the winter concentrate breaks down faster in warm water. On Mallorca that usually falls between late November and early December, depending on location. Palma's average air temperature in December is around 13 degrees, pool water lags one to two weeks behind, and a pool inland cools faster than one on the south coast. The weather agency AEMET gives you the forecast for your municipality; a ten-euro pool thermometer gives you the number that actually matters. The pool goes back into service once the water climbs above 15 degrees again, usually late March.

Two things apply to every option. The water stays in the pool: an empty pool can float or crack after heavy rain, and fill water is scarce on the island; see the article on filling a pool during water restrictions. And before winterizing, clean the pool thoroughly, backwash the filter, and balance the pH to 7.2 to 7.6. Skip that step and you just seal the dirt in along with everything else.

Option 1: active winterizing with reduced run time

The most common solution on Mallorca. The system stays on but runs only 2 to 4 hours a day instead of the 8 to 10 hours typical in summer. The water keeps circulating, chlorination stays on a low setting, and you see what's happening in the pool every week.

The electricity savings are easy to calculate. A 750-watt filter pump running 8 hours a day in summer uses about 180 kWh a month, roughly 45 EUR at 0.25 EUR per kWh. Running 3 hours a day in winter, that drops to about 68 kWh, or roughly 17 EUR. A variable-speed pump on its lowest setting costs even less. For what electricity generally costs on the island, see the guide to running costs on Mallorca.

What this option requires:

• Cut run time to 2 to 4 hours, ideally early morning when off-peak electricity rates are cheapest.
• Check pH and chlorine every two weeks. In winter, free chlorine of 0.5 to 1 mg/l is enough.
• Empty the skimmer and skim leaves after every storm. Rotting leaves eat up chlorine and discolor the water.
• Run the filter longer after extended rain, since rain pushes the pH down.
• Backwash the filter once a month.

This option suits rental fincas with winter guests and pools with a heat pump.

Option 2: passive winterizing with winter chemicals and a cover

Here the system shuts down apart from occasional circulation, and the chemicals take over. This is the option with the biggest savings potential, and also the one most likely to go wrong.

The winterizer is not chlorine but a mix of algaecide and scale stabilizer. A 5-liter container costs around 20 to 35 EUR on the island and covers 50 to 75 cubic meters. For an 8 by 4 meter pool holding about 45 cubic meters, you'll typically need one dose in December and a second in February.

Covers come in three price ranges. A basic winter cover (lona de invernaje) made of PVC-coated polyester is strapped down with eyelets around the pool edge; it keeps out light but you can't walk on it. A safety cover with support bars (cobertor de barras) can hold an adult's weight and is the usual choice for families with young children or dogs.

These prices are guide values from retailer pricing and quotes from pool companies on the island, and they vary with pool size, region, and how far the company has to travel. Many companies automatically switch to a visit every two weeks in winter and lower the price accordingly, but not all of them do. Ask what the winter rate includes; for how to spot a reliable provider, see the article on pool maintenance by a pool company.

Saltwater chlorination in winter: protecting the cell

In a saltwater pool, the most expensive wear part sits inside the equipment box: the electrolysis cell. Depending on the model it costs 300 to 800 EUR and lasts 5 to 8 years if it's looked after. Of all times, winter, when it's barely needed, is when many owners wear it out unnecessarily.

Below about 15 degrees water temperature, the cell produces almost no chlorine, and the electrodes age faster because the controller pushes more current through to try to hit the target output. Many units shut off on their own below 10 to 15 degrees or show a warning. If yours doesn't, set chlorine production to zero manually and just run the pump. Before winter, it's worth checking the cell: remove any scale buildup with diluted acid, so it's ready to go again in spring. Even with the system off, check the salt level once a month, since rain dilutes the water.

Whether saltwater chlorination or classic chlorine is the better choice is covered in the article on pool water: saltwater chlorination or chlorine on Mallorca.

Option 3: shutting down completely, and what applies to shared pools

System off, no chemicals, no checks until spring. On Mallorca that only works for above-ground pools that get refilled in April anyway. For an in-ground pool holding 40 or 50 cubic meters, this option ends up being the most expensive: come spring, you're looking at shock chlorination, several rounds of flocculant, days of filter run time, and often a visit from the pool company, together 150 to 400 EUR. That's more than option 2 costs for the whole winter.

Draining the water is a bad idea on the island for two reasons: the pool shell and the water shortage. The Balearic government tracks its drought levels on the Portal de l'Aigua, and some municipalities on Mallorca banned filling private pools with drinking water by decree in 2026. If you need 45 cubic meters of fresh water in March, depending on your municipality, that could be a problem.

In an urbanización, it's not the individual owner who decides, but the comunidad. Shared pools fall under Real Decreto 742/2013 on hygiene requirements for swimming pools, published in the Boletín Oficial del Estado. Many comunidades officially close the pool from October to May but keep the equipment running at a reduced level, because that's cheaper than restoring the water in spring. Whether the winter costs are in your community fees is in the annual statement; more on that in the guide to property management and the comunidad.

Do I have to cover my pool on Mallorca in winter?

No, it's not required. But a cover saves on chemicals, keeps out leaves and Sahara dust, and starves algae of light. If you're winterizing actively and want to keep looking at the pool, you can skip the cover, but you'll need to filter more often.

Can I switch the pump off completely in winter?

With option 2, yes, once the winterizer is dosed and the pool is covered. After heavy rain and once a month, though, run it for a few hours so the chemicals and water mix properly.

Bottom line

Winterizing a pool on Mallorca comes down to two things: slowing algae and saving electricity. Frost is not a factor. For most private pools, option 2 is the cheapest: one thorough clean, winter concentrate, cover on, check every few weeks. If you want to use or at least look at the pool in winter, reduced run time at around 20 EUR a month in electricity works well too. Shutting down completely almost never pays off. Whatever option you choose, if you have saltwater chlorination: turn the cell off below 15 degrees, or winter ends up costing you the most expensive part of the whole system.

If you're not sure what equipment your pool has, start with the overview on costs of operating, maintaining, and repairing a pool.