How to Winterize a Pool

How to Winterize a Pool ~ Seasons come and go, and so does your swimming pool. Be it an in-ground or above-ground pool, let’s look into the steps on how to winterize a pool—and how to open it in season.

A Must-Read: Best Pool Accessories

Inground Pool 

Prepping your pool for the winter is a lot more challenging than opening your pool for spring or summer. Your pool is going to stay untouched for a long time. Hence, you should make sure everything is perfectly set before you close your pool. 

Keep in mind that what you’ll see below is only standard protocol. Every seasoned pool owner somehow has its own process that works for them. You’ll find yours too once you’ve familiarised yourself with your own pool.

Step 1: Shock your Pool

At least 24 hours before actually covering your pool, do a pool shock if you want to make sure your pool is clear of any unwanted dirt or algae. 

Once you’ve done that, turn on the pool pump and leave it overnight to let the formula circulate around the pool and to let the chemical levels settle. 

The morning after, do a chemical test on the water to make sure it’s balanced. For better results, do this overnight so the sun won’t soak up your chlorine. 

Step 2: Clean Your Pool 

Scrub your pool walls and floor down to the last hidden corner. You can attach your pool brush to a telescoping pole to cover all areas. 

After scrubbing everything, collect and vacuum all the dirt. Doing all these will help knock out any potential algae growth and remove any sediment hanging around. 

When dealing with algae, you can also opt for algae brush to break up the algae. Vacuum up the algae once done. You’ll deal with them chemically later. 

Step 3: Check Pool Chemical Levels

Behind every successful pool, closing is chemically-balanced pool water. Get yourself a test kit to monitor your pool’s current pH and alkalinity levels. 

It’s important you have the appropriate levels so you can avoid corrosion and particle build-up from your pool. 

Neglect this part of the process and you may end up spending more money on cleaning and repairs. You definitely wouldn’t want to deal with that. 

Step 4: Add The Winterizing Kit 

Winterizing kits basically, provide you with chemicals you need to help your pool withstand the extreme temperatures. They usually come with pool shocks, oxidizers, winter algaecide, and winter stain preventer. 

Step 5: Drain Pool Water Below The Skimmer 

This is only needed if you live in a very cold climate. Otherwise, you can skip to the next step. 

The purpose of draining the pool down to a lower level is to avoid freeze damage and standing water. 

Step 6: Clean Your Filter And Pump 

Remove any dirt and gunk stuck in your filter and pool pump to avoid elements rotting in there! You wouldn’t want to deal with a dirty filter as soon as the pool opening season starts. It’s better you deal with them now. 

Step 7: Blow Out The Lines 

Pool pipes can be very delicate so unless you have experience in this, it’s better to let a professional handle it. Failing to execute this step means a whole lot of expensive repairs on your part. 

This step isn’t necessary if you live in a warmer climate. Unless your temperature reaches freezing points, there’s really no point in blowing out your lines.

Step 8: Uninstall Pool Accessories 

Pool accessories such as ladders and stairs can get in the way of putting your winter cover. Plus, they might freeze up and break if left out in the cold. Rust can also invade the finishes of your pool accessories. 

Step 9: Cover Your Pool 

The final step for closing your pool is covering it with a winter sheet. It’s better you use a darker color to lessen the UV rays that may permeate the sheet. 

Shielding your pool from UV rays is essential to prevent them from soaking up all the chlorine in the water. Remember, more chlorine, higher sanitation levels throughout the winter. 

Secure the sheet with weights and place a pool cover pump to prevent elements from weighing down the pool cover. 

Above-Ground Pool

The process is similar to closing an in-ground pool. You’ll have to test the water, clean the pool and filter, and winterize your pool water and filter. 

One thing you have to be vigilant about when closing an above-ground pool is potential leakages. Above-ground pools are notorious for leaking out during the winter season. 

In effect, many above-ground pools crack during the cold season because of leaks. Make sure you avoid this mistake.

Why Winterize

Try to observe your pool while it’s still out in the open. More often than not, swimming pools are magnets for debris, leaves, and even insects. Every time you take a peek, there’s always bound to be some sort of particle floating about on your pool surface. 

Don’t worry, though. It’s completely fine to leave your pool exposed during the summer since you’ll be using it throughout the season. But once winter comes, that’s a different story. 

Winters are for staying in and cozying up near the fireplace. You won’t have the opportunity to use your pool during this season since it’s very difficult to go outside. In other words, you won’t be able to clean nor use it. 

What happens next? A growing pile of dirt, debris, and all sorts of things left to rot during the off-season. 

And since you won’t be outside to take them all out, it can leave a mark on your swimming pool—clogged skimmers, unbalanced pool chemistry, or even corrosion. 

Opening Your Pool

Winter is almost over and you’ve been itching to take out the cover. But the pool isn’t quite ready yet for swimming—you’d have to properly open your pool first! 

Step 1: Drain Water From The Cover 

Removing your pool cover abruptly isn’t the way to go. That’s just messy and unsanitary due to the old water lying on top of the cover. 

Instead, use a cover pump then let it do its magic. Don’t forget to take out fallen leaves or other debris sitting on the surface of your pool cover. 

Step 2: Unveil The Swimming Pool 

Now, for the exciting part. You finally get to take off the cover! 

It’s recommended you do this with a friend. That way, it’ll be a much easier and smoother process. 

It’s normal for old water or debris to fall off on your pool while you unveil it, so don’t freak out when this happens. Either way, you’ll get to take care of those later once you shock and vacuum your pool.

Step 3: Set Aside Your Pool Cover

Before storing your pool cover, make sure it’s completely dried out to avoid mildew buildup. Don’t forget to clean it with a pool cover cleaner before storing it in a cool, dry place. 

Make sure it’s all folded up nice and clean before you leave it again until the coming winter. 

If you winterized with water weights, dry them up completely as well before storing. 

Tip: Never leave your pool cover or weights on the floor so you can avoid dealing with a bug infestation. 

Step 4: Clean Pool Water 

Going back to the debris on the pool, it’s time to deal with them. 

Using your skimmer, glide through the whole surface of your pool in order to clean out floating gunk or debris. It’s important to take out the big stuff now before dealing with chemical balancing later. 

Step 5: Remove Plugs and Gizmo 

Take out the plugs you used to seal your pipes as well as your gizmo you installed in your skimmer. You won’t be needing them anymore until next winter. 

While removing them, it’s normal for some bubbling up to happen. This only means that water is flowing back into the pipes. 

Step 6: Reinstall Your Pool Accessories And Equipment 

Every pool accessory you’ve taken out like your ladder, diving board, step rails, put them back in. Also, do not forget to reconnect your filter, pump, heater, everything else. 

Step 7: Add Water 

If you’ve done a little bit of draining before the winter, you’ll need to refill your pool with fresh water. It’s also normal to lose some water throughout the winter. Either way, you’ll have to add some water to your pool. 

Be sure to use a hose filter in order to prevent impurities from entering your pool. 

Step 8: Re-run Your System 

It’s time to get those machines up and running again. Prep the pool pump and activate the circulation and filtration system. 

Step 9: Add A Metal Sequestrant 

A stagnant pool will end up accumulating metal components throughout the winter. In effect, this will likely stain your pool eventually. 

To avoid that, add a metal sequestrant and let the filtration and circulation system run for about two hours. 

How to Winterize a Pool

Step 10: Test The Water 

After letting the pool set with the metal sequestrant, it’s time to test your pool for the chemical balance once again. 

Grab your test kit and make sure your chemical levels are in tip-top shape. 

Tip: When balancing, always follow this order: alkalinity, pH, calcium hardness.


Again, the process is very similar to opening in-ground pools. There is not much difference when opening, if at all. 

Remember to just be vigilant about leaks when dealing with above-ground pools. Check your pool liner as well for tears and such. 


Unveiling your pool for spring is always something to look forward to. But the question is—when is the optimal time to do so? 

Once you feel that spring is about to blossom, keep an eye out for consistent temperatures. If it’s always hitting in the 60s or 70s, it’s time to open the pool. 

Keep in mind you wouldn’t want to open the pool too early or too late. Unveil your pool too early and you’ll risk freezing it and destroying the structure. Open it too late? Prepare for algae infestation due to moist and heat. 

Wrap Up 

Frankly, opening your pool is much more straightforward than closing it. When winterizing, you really need to anticipate every result cold weather may give to your pool. 

It will take a bit of experience to actually get it right, so don’t get frustrated if you end up compromising some areas of your pool once you unveil it. 

On the other hand, you’d have to worry more about after-care when opening your pool. Meaning, you should pay more attention to treating your pool after a long period of being stagnant. 

To make it easier for you, be aware of some of the common mistakes most pool owners make. 

When opening pools, most owners tend to shock their pool immediately after cleaning up everything and setting up. Mind you, this is wrong. Give your water time to adjust. 

Wait for about half a day to let it completely circulate, only then is it best to shock your pool. 

As with closing your pool, never do it haphazardly. Sure, your pool will stay cloaked all winter-long, but that doesn’t mean it’s okay to leave it covered dirty. Remember, the water that was there during the winter will be with you come spring. Hence, always make sure you do a good job of cleaning!

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