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How To Close a Pool Properly: The Complete guide

The summer is here, and it is time to break the swimsuits and shades out. With excitement, you rush to the poolside to admire your wonderful swimming pool, instead of sparkling, inviting water, you a swampy pool with algae and other uninvited guests in there. Why is your swimming pool in such a bad state? The answer to that question is simple, you did not prepare your pool properly. In this article, we will outline the best and most effective way to close or winterize your pool. 

Remember, closing your pool in the correct way will save you time and energy, also in the long run, it will be more cost-effective. 

closing a pool

Why is Closing Your Pool Important? 

Closing swimming pools is not just reserved for commercial swimming pools, it is a necessary part of any swimming pool maintenance schedule. 

During the summer/spring season, you leave your pool uncovered and clean it regularly; however, plenty of dirt still settles on the surface and inside the swimming pool. It is a constant effort to keep it clean. Therefore, if you failed to cover the pool, or you did cover it but you just didn’t take the time to do it properly? You would have to go through a lot of steps to get it back to the way it was before. 

Pool Closure Timing 

Keeping your swimming pool clean means that you will need to carry out certain steps at certain times. It is vital that you begin the process of winterizing your swimming pool at the correct time.

Check the weather(the temperature) this will help you to determine when you should close your swimming pool. 

If the temperature in your area is usually less than 65°F (18°C) during the winter months, wait for the temperature to drop below the 65 marks before you close the pool. When the temperature is low, algae can’t survive therefore, if you wait until the temperature drops, the chances of your pool experiencing a significant algae breakout will be minimal. 

How to Close Your Swimming Pool 

The way you winterize your pool will depend largely on your location, the temperature, and the overall climate. Taking water out of your pool will prevent problems occurring especially when the water turns into ice.  Making sure the chemicals are balanced could essentially reduce the chances of pool chemistry issues. Also, if you decided to use a winter cover, it would protect your swimming pool from the winter weather. A cover designed for safety only will prevent accidents from happening. 

Is your location very cold during the winter? You would need to push the water out of the pump to avoid damage to the pump.

 What You Are Going to Need 

You are going to need various items to facilitate the process of closing your swimming pool. Here is an extensive checklist of items that you are going to need to close your pool. 

  • Items such as ladder, air compressor, and wet and dry vacuum cleaner 
  • Test strips or water testing set 
  • Chlorine or bromine (or use the sanitizing chemical that you already use)
  • pH increasing chemical (you might not need it but have it to hand anyway) 
  • pH decreasing chemical (you might not need it but have it to hand anyway) 
  • Alkalinity decreasing chemical(if necessary) 
  • Calcium hardness increaser(if needed) 
  • Cyanuric acid 
  • Algaecide 
  • Shock chemical 
  • Metal sequestrant 
  • Pool winterizing equipment
  • Winter pool covering
  • Weights for pool cover 
  • Plugs(rubber) 
  • Gizzmo 
  • Swimming pool brush 
  • Algae brush or scrubber 
  • Telescoping pole 
  • Swimming pool vacuuming machine 
  • Wash The Pool 

The most important thing to do before you do anything else is to wash your pool using a special brush designed for cleaning pools. Thoroughly scrub the surfaces of your pool, then begin the process of cleaning your pool with the vacuum machine. Utilize the algae brush if you have any algae festering in your pool.

  • Water Testing 

 If you already have a testing set, you can use this to test the water. However, if you don’t have one, you can actually collect some pool water and take it to a pool shop to have the water tested for you. In fact, this is the most reliable way of testing your water, so if you have not tested pool water before, this might be the best option for you. 

When you test for chlorine, you should ensure that the chlorine levels are less than five parts per million.

  • Winterizing Chemicals 


Use algaecide to reduce potential algae growth growing in your pool during the colder months. If you are using a cover that has a mesh panel then you might need to use more algaecide, you might need to add twice as much. 

Metal Sequestrant 

This is for swimming pools that use water with high metal content, for instance, if the pool water is sourced from a well. You would need to use a metal sequestrant prior to closing the pool to ensure that metals do not oxidize in the swimming pool and cause unsightly staining. 

Pool Enzymes 

Pool enzymes can aid algaecides by working to eliminate organic contaminants. 


Winterpills would be needed if you live in a colder area because chlorine tablets will not dissolve properly when used for closing a pool. You would need to use something that is specifically meant for use in a closed swimming pool. WinterPill is a good option to consider. 

You might need to use an antifreeze but if you blow out your lines well enough, you can skip the antifreeze step. 

Get an antifreeze that is suitable for 10°F (-12°C) weather, if the area you live in is typically colder than this, you should search for a product that can manage colder temperatures. 

Caution: Most people think all antifreeze products are the same, they are not. The type you use for cars or vehicles, in general, is not the same as the type that you use for swimming pools, make sure it is labeled “suitable for use in swimming pools.” 

  1.  Shock The Pool 

A couple of days before you plan on shutting the pool, shock the pool by using a pool shocking product or you can use larger quantities of chlorine. 

Use the pool shock product according to the instructions on the packaging, you might need to increase the dose if you notice any algae forming in the swimming pool. 

You would need to turn the pump on and leave it on during the night to allow for even distribution of the chemicals. The next day, test the water to check the chemical levels. 

5. Reduce The Water Level 

This step is specifically for people who live in a colder climate. If this does not apply to you, you can move on to the next step.  If you live in a cold climate, you should consider removing some of the water just before you cover the pool. This prevents damage caused by freezing, you should ensure that your water is below the tile border. Even once you close the pool, you should still continue to monitor the water levels. 

How much water you take out will depend largely on the type of pool cover you decide to use, and also the pool surface that you have. Make sure you use the cover according to the instructions that come with it. 

Make sure the water is about an inch lower than your skimmer or tile line. 

Non-Vinyl Pool Liner 

If the pool cover you are using is a solid one, you need to make sure that the water is about six inches below the skimmer. If you use the mesh type of cover then you should be lowering the water level to about 18 to 26 inches below the skimmer. For automatic swimming pool covers, make sure the water is just below the skimmer. 

Reducing the Water Level 

Reducing the water level is pretty simple actually, all you need to do is pump the water out until it reaches the level you want it. Remember, however, that you did add some chemicals to the pool so be careful when it comes to pumping wastewater out of the pool. 

When it comes to pumping water out of a pool, you need to make sure you check with your local authority to ensure that you are following the correct legal guidelines for your area. 

 Backwash and Clean the Filter and Pump

Backwashing your filter is a vital part of closing your swimming pool. You definitely don’t want to cause problems by leaving lots of dirt in your filter, it will only build up over time and cause unwanted problems. 

Backwashing a Cartridge Filter 

Take the filter out and clean using a pool filter cleaner. You can also use muriatic acid if you want to. Once you have cleaned the filter, make sure you rinse it well and leave it to dry. 

Backwashing a Sand Filter 

When you are backwashing a sand filter, make sure you use a filter cleaner that is made specifically for sand filters. 

When you are cleaning a sand filter, make sure you turn the valve back to the filter option once you have finished backwashing. Remove the water from the pump and swimming pool heater(if there is one installed) Place the plugs into the skimmer basket and keep them there. 

Backwashing or Cleaning a Diatomaceous Earth (D.E.) Filter

When you are cleaning a DE filter, make sure you use a cleaner that is specifically designed for DE filters. You can also backwash these filters using the same method that you used to backwash a sand filter. 

  •  Blow The Lines Out 

You can totally skip this step if you live in a place that has a warmer climate. The whole point of blowing out the lines is to prevent freeze damage. 

If the temperatures drop pretty low where you live, you should really be considering blowing out your lines. The whole point of doing this is to remove all water from the lines, the filter and the pump. This should totally prevent ice damage, when you do this, you will not need to use antifreeze at all.

Blowing out the lines could actually cause damage to the lines because it does require a little bit of pressure. You need to do this really carefully in order to avoid causing damage to the lines. If you are not sure you can do this, it might be time to call in an expert, you will save money in the long run if you pay an expert to do the job as opposed to you trying to do it yourself when you have no idea what you are doing. 

Be Safe and Clear The Deck 

Detach the swimming pool ladders and anything else that is around the pool. Leaving pool ladders installed is not a good idea because they might even get damaged during the colder months. Also, any other item that could get damaged during this period, store them away in a dry place. 

skimmer baskets. You can toss the fittings into the clean skimmer basket to help you keep track of them.

  • Winter Cover 

Place a winter cover over the pool, you can choose which type you want to use. 

A normal winter cover 

This type of swimming pool cover will serve as protection for bacteria and contaminants. You can keep the cover in place by using pool weights. You should also consider getting a swimming pool cover pump, this will remove any water that has gathered on the pool cover. Make sure you clean your cover and remove any debris from it regularly. 

  • Safety Cover

This is another option, these are actually more expensive but they protect your pool and they protect animals from falling into the pool and drowning. You can either opt for the solid type of safety cover or go for the mesh type. They both work well to stop animals from getting hurt. 

To Conclude

Knowing how to close your pool to protect it during offseason, is important, however, if you really don’t feel confident in closing your pool, don’t be afraid to hire a professional to get the job done for you. Closing a pool involves cleaning, testing, adding chemicals and other steps therefore if this is too much for you, hire an expert. 

Posted in pool maintenance

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