How to Close Your Pool for Winter, the Way the Best Hotels Do It

Every fall, hotels on Lake Como, in the Alps and along the northern Mediterranean put their pools to sleep. They do it the same way every year, with checklists, because a pool that's closed carelessly in October is an expensive repair in April.

You can do the same at home. Closing a pool properly takes an afternoon, a few supplies and a little patience. Here is how, in order, with notes on what professional pool teams do that most homeowners skip.

A quick note before we start: every pool is a little different. Your equipment's manuals and your local pool store know your setup better than any general guide, so treat what follows as the framework and check the specifics for your system.

When to Close

The usual rule of thumb is to wait until the water stays below about 65°F (18°C). Below that, algae growth slows dramatically, and your chemicals have an easier job all winter. Close too early, while the water is still warm, and you're more likely to open a green pool in spring.

If you live somewhere it rarely freezes, you may not need to close at all. Skip to the section on warm climates at the end.

What You'll Need

Step by Step

1. Clean the pool thoroughly

Skim, brush the walls and floor, and vacuum. Anything organic you leave behind (leaves, pollen, insects) becomes food for algae over the winter. Resort teams treat this as the most important step, because it's the one that decides what the water looks like in spring.

2. Balance the water

About a week before you close, test and adjust. Typical targets:

Balanced water protects your surfaces and equipment from corrosion and scaling while the pool sits still for months.

3. Shock it

Shock the pool a few days before you close and run the pump so it circulates. Let chlorine levels fall back toward normal before you add winter algaecide, since very high chlorine can weaken some algaecides.

4. Lower the water level

How far depends on your cover and climate. With a mesh safety cover in a freezing climate, water is commonly lowered a few inches to below the skimmer mouth so ice can't crack it. With a solid cover, many manufacturers recommend keeping the level higher, just below the skimmer or tile line, because the water helps support the cover. Vinyl liner pools shouldn't be drained low, since the liner can shrink and pull away from the walls. Follow your cover manufacturer's guidance here.

5. Clear the lines (in freezing climates)

This is the step that prevents cracked pipes. Use a blower or shop vacuum to push water out of the return lines, skimmer lines and any cleaner or spa lines, then plug each one as the air bubbles through. Many pool owners add pool antifreeze to the lines afterward for extra protection. If this is your first time, it's worth paying a pool service to do it once and watching how they work.

6. Winterize the equipment

Drain the pump, filter and heater completely. Open the drain plugs and leave them out (store them somewhere you'll find them in spring, like a labeled bag tied to the pump). Clean or backwash the filter, and if you have a cartridge filter, take the cartridges out, clean them and store them dry. Turn off power to the equipment at the breaker.

7. Add winter chemicals

Add winter algaecide or your winterizing kit according to the label, with the pump still running briefly if your lines are not yet cleared, or poured around the perimeter if they are.

8. Remove accessories

Take out ladders, handrails, diving board hardware if your manufacturer recommends it, cleaners and floats. Clean them and store them dry.

9. Cover it

Fit the cover snugly. Above-ground pools usually need an air pillow under the cover to absorb ice expansion and shed water. In-ground solid covers are often held down with water bags. Through the winter, keep standing water and leaves off the top of a solid cover with a cover pump, because the weight can damage the cover and the pool.

What Hotels Do Differently

Resort pool teams in seasonal climates tend to add a few habits that are worth borrowing.

If You Live Somewhere Warm

In places where freezing is rare, many owners keep their pools open year-round and simply adjust. Run the pump for fewer hours, since cooler water needs less filtration, keep chemistry balanced, and keep the pool skimmed as the trees drop their leaves. If your system has a freeze protection setting, make sure it's on, so the pump runs during the occasional cold night. A solar or thermal cover can extend comfortable swimming by weeks.

The Payoff

A pool that's closed with care opens with clear water, working equipment and no surprises. Which leaves you free to spend the winter thinking about warmer water somewhere else! When you're ready, our guide to where to swim this winter is a good place to start.

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