How To Winterize Pool – Above Ground And In Ground Pool Guide


Owning a swimming pool is mostly fun and games, but it also requires a bit of maintenance, and learning how to winterize a pool is among the most important parts of it. In this article we’ll show you how to winterize an above-ground pool and how to winterize an inground pool, so you don’t have to think about it too much.

When Is The Right Time To Winterize?

It depends on place to place, but in places, with strong winters an unwritten rule is to start to winterize your pool once the temperature drops 18°C (65°F). This way you’ll let nature take care of the algae, while you’ll have more than enough time to do all the preparation needed before you close your pool for winter.

These 10 steps will help you do it as easy as possible:

1. Purchase The Chemicals

The first step in winterizing the pool is to purchase all the needed chemicals and other accessories:

  • Winterizing chemical kit or chemicals
  • pH increaser
  • Alkalinity increaser
  • Calcium hardness increaser
  • Pool shock chemicals
  • Algaecide
  • Above ground pool skimmer cover
  • Expansion plugs
  • Return line plugs
  • Pool winter cover with winch, cable, and clips
  • Water bags
  • Swimming pool antifreeze (if needed)

2. Clean Your Pool

The worst thing you can do is to leave your pool to sit dirty for a few months and let algae or mold to develop. Use a pool vacuum and go through the whole pool, brush the walls, and skim the surface. This way you’ll remove any unwanted leftovers and taking care of your water balance should be much easier.

3. Test The Water

It is irrelevant what type of swimming pool you have, you’ll have to test the water chemistry before you close it. Use test strips or water test kits to determine the state of your water, and if needed, react.

Here are some values you should look for:

  • pH should be between 7.4 and 7.6
  • Alkalinity level should be between 100 and 150 ppm, while an ideal value is 125
  • Calcium hardness should be between 175 and 225 ppm
  • Chlorine should be between 1 and 3 ppm

The ideal scenario is to leave the levels closer to the high levels to avoid the possible negative effect of natural decrease. Also, if the temperature rises during winter, you could test the water to check if everything is OK.

4. Winterizing Chemicals

Once you’re certain that the level of chemicals in water is optimal, it is time to add winterizing chemicals. This task shouldn’t be complicated at all – all you have to do is to follow the guide written on a winter closing kit.

Besides that, you should shock the pool to give your sanitizer a boost, just make sure to hit the right amount and add a bit of algaecide – also done by following the instructions. This will prevent algae from appearing during winter.

5. Clear and Store the Lines

Even mild winters can cause damage to your pool lines due to ice, so by removing and storing them, you’ll prevent any damage. The task itself is quite simple – disconnect the lines, let the water out, put them somewhere to dry, and place the lines away from the direct sunlight. Before you store them, make sure all the water is out and the lines are dry, or else you risk the formation of mold.

6. What To Do With Skimmer

When it comes to the skimmer, it is up to you how you want to protect it. Start by removing the skimmer basket and placing it in a dry place. Then, it is up to you whether you’ll cover it or not. You could use a plate to cover the whole skimmer, which will seal the elements and you won’t have to drain the pool below the skimmer line. However, if you decide to go without it, make sure to check it everything is OK frequently, especially when the water starts to freeze. It may cause your skimmer to crack due to ice or snow load.

7. Preparing The Filter And Pump

The filter and pump are the next ones in the line of things to take care of.

The Pump

It should be removed by removing all drain plugs, then removing the pump, chlorinator, and hoses. Place them all inside and in the same place so you know where they are when the time to relaunch the pool comes.


It depends on the pool filter type:

  • Sand: Turn the „Winterize“ setting on your multiport valve, let it drain by removing the drain plug. Remove a bleeder valve and a sight glass and place them along with the pump. Move your filter inside.
  • Diatomaceous Earth: Drain, rinse with a hose, and leave the valves open.
  • Cartridge – Drain, rinse it, leave the valves open and store it inside.

8. Clean The Accessories

If you leave the toys or other stuff in the pool during the winter, they can get damaged or even worse, they can cause damage to your water or your pool, so make sure to remove everything that can be removed. Once you remove accessories, take some time to clean them using a pool surface cleaner, let them sit in the air to dry, and place them somewhere away from direct sunlight until needed again.

9. Drain The Water

Whether you should drain the pool or not is completely connected to the way how well you’ve protected your skimmer. If the water freezes above the skimmer level, it can cause your pool to freeze and crack. This means that if you don’t use a winter skimmer cover plate, you should drain the water level below the skimmer.

However, if you have a winter skimmer plate, all you have to do is to remove the hose and let it drain, install the plate and that’s it.

How Much Should You Drain

The level of drainage depends on your pool type:

Aboveground pools

  • With vinyl pool liners, you’ll have to drain the water approximately 1 inch below the bottom of the skimmer mouth, but it is OK to go even further.
  • With other pools, going even 6 inches below the skimmer is recommended.

In-ground pools

  • For standard floating winter cover, don’t drain the water more than 6 inches below the bottom of the skimmer.
  • If you plan to drain the pool completely, switch your pool filter to „drain“, place the pool hose somewhere where you’ll avoid flooding.

Winter Cover

  • For mesh pool cover you should drain your pool down to 12-18 inches to prevent evaporation while giving the pool enough space to fill with melting snow.

10. Add The Pool Pillow And Cover

The next step to winterize the pool is to add the pool pillow and the pool cover.

Adding  The Pool Pillow

A pool air pillow is one of the most important parts of how to winterize a pool guide and it will help your pool stay in great shape for a longer time. It is also known by the name of ice compensator due to its ability to compensate for the pressure of the snow and ice that can gather on the top of the pool cover, protecting the sides of the cover and the walls of your pool this way and lowering the chance of any damage to a minimum.

This will also help you move the debris, dirt, and similar stuff to the sides of the pool, making it easier to clean when the relaunch time finally arrives.

 Don’t over-inflate your air pillow, 50-60% will do just fine. Remember, the snow will press the pillow, and if too inflated it may pop easily. Once you blow it up, move it to the middle of the pool. If needed, you can tie it to a side of the pool using a thin rope if you don’t have anything designed to keep the pillow in the middle of the pool.

When inflated, use duct tape to seal the valves and the seams to reduce the loss of air.

Installing The Pool Cover

The last thing you’ll have to learn when it comes to how to winterize a pool is to install a pool cover. Make sure you secure it well after you’ve finished. The key to a good pool cover that will serve more than well lays in a combination of winter cover clips, a cable, and a winch. This way you’ll be certain it will stay firm and in place no matter how hard the winter is. If there is a space, you can also use water bags to keep it even more secure.

If you think about using rocks, bricks, wood, basically anything that can cause damage to your liner if it falls into the pool, don’t.

During the winter, pay attention to your pool cover, check it regularly, and keep it as dry as possible.

Call A Professional If Needed

Sometimes, especially if you do it for the first time or you’re still uncertain how to do it, it is better and cheaper to call up a professional to help you do it, which is by far better option than to do something wrong and damage your pool so you won’t only lose money but also the time you’d be spending in the pool, otherwise.


Here are the answers to some of the most frequently asked questions about how to winterize an above ground pool and how to winterize an inground pool.


Q: What chemicals do you put in the pool for winter?


Chemicals used to winterize pool can be found in a winter closing kit. However, if you decide to buy each individually, you’ll be needing the following:

  • Chlorine-free pool shock
  • Stain and scale treatment
  • Winter algaecide
  • Winter floater

These are used beside all the other chemicals used to control your pool chemistry and are added according to the instruction manual on the package.

Q: How do you close an above ground pool for the winter?


The shortest possible answer to this question is by removing anything that can be removed from your pool, adding needed chemicals to balance the water, shock it and winterizing it, lowering the water level, installing an air pillow and covering the pool itself.

Q: How far down do you drain your pool for winter?


It depends on your pool type. Most of the time, 6 inches below the skimmer will be enough and the vast majority of pool professionals suggest it. However, if you have an unusually shaped pool, it is better to contact your pool manufacturer or a professional and ask for a recommendation.

Q: How much does it cost to winterize a pool?


The costs of winterizing a pool can vary and go from $50 to $700. Hiring a professional will cost the owner between $125-$375, depending on the pool type, size, etc. If you decide to DIY, you may come with the south portion of the price, but you’ll have to be careful and do everything by the books to avoid any damage.

Q: What happens if you don't winterize your pool?


It depends on the winter, but in the worst case scenario, if the winter is harsh, the water will freeze and your pumps, filter or pool liner can crack and break. Winterizing the pool will prevent this from happening and keep your pool safe during the winter.

Q: Does an above ground pool freeze solid?


Yes, an above ground pool can also freeze solid, which is why you should learn how to how to winterize an above ground pool and do it every winter. When you winterize pool you’ll prevent any damage that can occur during winter.

Q: Are pool winterizing chemicals necessary?


The pool can be closed without pool winterizing chemicals, so you don’t need to use any additional chemicals besides winter algaecide to winterize the pool. However, the winterizing kit serves to help you make sure everything is OK no matter how harsh the winter is.

Globo Surf Overview

Learning how to winterize a pool will prevent any unnecessary money loss and keep your pool in a good shape. This article will give you all the needed information so you can be relaxed until the time to use it comes again.

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Globo Surf
My name is David Hamburg. I am an avid water sports fan who enjoys paddle boarding, surfing, scuba diving, and kite surfing. Anything with a board or chance I can get in the water I love! I am such a big fan I decided to start this website to review all my favorite products and some others. Hope you enjoy!