How To Winterize A Pool – 8 Steps to Doing It Right

In This Post, I Tackle the Often Overlooked Task for many Swimming Pool Owners; How To Winterize A Pool.

Many pool owners make this mistake – they just simply put a cover over their pool at the end of the swimming season, thinking that they’ll take care of the water next year.

Then, after a few months, the Sun begins to shine again and they remove the cover with much anticipation and glee…only to find out that their spotless pool has been turned into a swamp! But often, that’s just the beginning of their problems. Chances are, that they also forgot to drain their pipes and now they’ve been freeze-damaged! If this is the case, they are staring at thousands of dollars in repair costs.

Preparing a pool for the winter, or ‘winterizing’ it may seem like a daunting, complicated task. Today though, I am going to teach you how to do it without breaking too much of a sweat. So let’s begin.

The actual winterizing process depends on where you live. If you live in a state where it doesn’t snow but the weather is a bit too cool for swimming, you don’t have to worry about your pipes freezing.

If your pool is in Porland though, where it can snow fairly frequently all winter, you’ll have to blow out all the water from the pipes. On the plus side, you’ll have fewer problems with algae as lower temperatures prevent algae and bacteria from proliferating.

Please note that if you’ve been maintaining the pool properly all season, winterizing it will entail a lot less work. Preparing the pool for winter is all about anticipating what could go wrong and preventing it. For example: If you have children around the property, a safety cover is a must as it prevents drowning related incidents.

Step 1: Give your pool a thorough cleaning.

If you clean the pool at regular intervals, then this step is going to be very easy. You can just use a telescoping pool or a robotic pool cleaner if you have one. In either case, pay special attention to the corners as that’s where dirt and algae like to settle.

Make sure that the pool is completely devoid of algae and other debris. If you pool is dirty, you’ll have to manually vacuum out all the debris. This is easier than it seems and I have posted a detailed article on how to manually vacuum your pool.

Step 2: Test Water Chemistry.

You can use a commercially available test kit to check and balance water chemistry. The three most important parameters are pH, alkalinity and Chlorine levels. Make sure that all of these are within the recommended range. (All test kits come with instructions). Chlorine levels should be below 5 parts per million. If any higher, Chlorine will prevent other additives from doing their job properly.

You should shock your pool at the beginning and end of each season. As you may already know, shocking is usually done at night so that the pool is ready to use by morning. However, if you don’t have that much time, use a non-chlorine shock. This shocking method takes very little time and is often employed at busy pools.

Step 3: Add Chemicals For The Winter

The type of chemicals that you add depend upon your location, climate etc. A pool winterizing kit can be very useful as it’s an all-in-one solution. However, we;ll quickly run over all the important chemicals one by one.

  • Algaecide: As the name suggests, this chemical kills algae and prevents spores from blooming.
  • Pool Enzymes: These are usually added to counter contaminants such as sunscreen. Pool enzymes act against organic contaminants and help to check their growth.
  • Metal Sequestrant: This prevents metals in the pool water from settling, oxidizing on and staining pool surfaces. You’ll only need this if your water contains high levels of metals (usually depends upon the source. Water from a well usually has high amounts of metals).
  • Winter Pill: Regular sanitizers may not dissolve properly due to the low water temperature and the fact the pool pump will be turned off. Winter Pills are designed to dissolve slowly over a period of time in a closed pool. 
  • Antifreeze: Technically, this is optional – it’s not required if you blow out all the water from the pipes. However, even a little bit of water is enough to cause freeze damage. So it is better to err on the side of caution and protect your pipes with antifreeze.

Get hold of anti-freeze that is safe to use in pools as the one meant for cars is toxic.

Also, the anti-freeze should be rated according to the temperatures that you usually encounter during winters.

Here’s how much antifreeze to use, based upon the thickness and length of PVC piping.

Pipe size (Diameter)Gallons of Antifreeze per 10 feet of pipe
1 inch1/2
1.25 inches3/4
1.5 inches1
2 inches1-3/4

Step 4: Lower the water level

This step is only required if temperatures in your area fall below freezing. If you live at a place where the weather is comparatively warm, skip to the next step.

Please ensure that the pool has been shocked before proceeding to lower water level.

Lowering water level is easy, just pump to waste until the water level is where you want it to be. Usually, this is below the bottom edge of the skimmer.

Remember, water level also depends upon the type of cover you’re using. The water supports the weight of the cover and snow/debris that accumulates on it. So you also have to pay heed to the cover manufacturer’s instructions.

Step 5: Backwash & Clean Filter & Pump

You can skip this step only if you want debris and gunk to remain trapped and rot in the filter all winter.

Clean the filter thoroughly so that you have a nice/fresh one to use at the beginning of the next season.

Step 6: Blowing Out The Lines

This is the only step that makes winterizing a pool seem intimidating. Actually, it is not very difficult but the margin for error simply does not exist. You have to get it absolutely right otherwise you’ll pay through the nose to get things repaired.

You have to get all the water out of the pool plumbing system. However, you cannot use excessive air pressure as this too can damage the equipment. Hence, it is recommended that you use antifreeze and hire professional help unless you absolutely know what you’re doing.

Needless to say, this step is not that critical if your region does not experience sub-zero temperatures.

Step 7: Remove Pool Accessories

Accessories like ladders can become damaged due to the prolonged exposure to chemicals. They also prevent the pool from being covered completely. This leaves room for debris to get into the water. Partially covered pools are also more prone to accidents as animals and kids can fall into the water.

Therefore, it is a good idea to remove all pool accessories and store them securely.

Step 8: Install Pool Cover and Safety Cover

There are plenty of choices for pool and safety covers. Pick the ones that suit your needs and budget. Note that you’ll have to use weights to prevent the cover from sinking into the pool (Read manufacturer’s instructions). Also, the cover needs to be brushed periodically as snow and debris weight it down over time.

You might also consider investing in a pool pillow (pressure compensator) if you have an above ground pool.

Usually, I recommend that you do most things yourself as this saves money and encourages you to learn. However, if you’re a new pool owner or doing this for the first time, I’d advise recruiting the services of a professional. If not, get a seasoned pool DIYer to help you out.

I hope that you found this article helpful. Please share your experiences in the comments section below.

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