Above-Ground Swimming Pool

How to Winterize Your Above-Ground Pool: A Comprehensive Guide

Winter means cuddling up by the fireplace, breaking out your winter wardrobe, and getting cozy. However, the season also heralds the end of swimming and having fun in the sun. Just like you, your swimming pool needs to get ready for the colder months.

Swimming pools are really not the best of friends with cold, frost, snow, wind, and changes in the weather. Above-ground pools are particularly susceptible to damage over the winter months. From the pool liner and pipes to pumps and motors, the harsher elements can leave their mark.

This is why winterizing an above-ground pool is a necessity, especially in colder climates where hard freezes are more likely to occur. If you’re reading this post, you’re probably wondering how to go about winterizing your above-ground swimming pool. I’ve put together this comprehensive guide on the topic, complete from A to Z.

Why Is It Necessary to Winterize an Above-Ground Pool?

Frozen Swimming Pool

Winterizing a pool — particularly above-ground models — is recommended to keep them in tip-top shape. As the pool is likely to remain unused throughout the colder months, it’s a must, to prevent damage. Winterizing keeps the pool and water clean, prevents algal blooms, and protects against frost. Plus, doing so ensures your pool is as close to ready-to-use as possible when summer arrives!

Is it necessary to winterize an above-ground pool in cold climates?

Yes, it is. In very cold climates, hard freezes are more likely to occur, causing severe damage to above-ground pools. When temperatures drop below 32°F/0°C, frost sets in, threatening your above-ground pool equipment and parts. For example, the frame, liner, lines, motor, pipes, and other vital parts of your pool are at risk. The resulting damage can delay summer swimming, and be costly to repair.

Is it necessary to winterize an above-ground pool in warm climates?

No, it is not. If you live in a warm area where temperatures don’t reach or drop below 0°C/32°F, winterization is optional. Instead, you can simply maintain your pool as normal until the warmer months arrive. Because all pools — including above-ground types or those with pool liners or fiber-glassing — are best kept filled with water, there’s no difference.

When Should I Start Winterizing My Above-Ground Pool?

October is the best month to start winterizing an above-ground pool for those in the Northern Hemisphere. Conversely, in the Southern Hemisphere, winter sets in in June. However, you can start winterizing even earlier if you’re further North or South — or somewhere where the cold weather arrives sooner. Ideally, you should begin just before temperatures start to drop and rain, snow, and frost set in.

How to Winterize an Above-Ground Pool in 10 Steps

Winterizing a pool is quite an elaborate task. From balancing the pool water to wrapping her up, it can be time-consuming. I’ve made the process easier by listing all the steps you need to take, from winterization preparation to post-winterization care.

Watch this video for more information

Step 1: Buy Your Above-Ground Pool Winterizing Equipment

If you’ve never winterized your pool before, chances are, you may not have the right equipment to do so. You need various tools, chemicals, and accessories for the job. Buy or coordinate them before you start, to avoid unwanted delays and trips to the hardware or pool store.

What You’ll Need:

Not sure what to buy? Here’s a list of the essential items you’ll need to winterize your above-ground pool:

  • Pool closing chemicals or kits to maintain the pool water over winter.
  • Water balancing chemicals to clean and prepare your pool water.
  • Algaecide and stain and scale treatments to reduce build-up.
  • A telescopic pole and pool cleaning attachments to clean your pool prior to closing.
  • A pool cover, leaf net, cables, clips, and winches to cover your pool.
  • A pool cover pillow and connection system to offer extra support to your cover.
  • A winter cover seal and weighted wall bags to keep your pool cover shut in harsh conditions.
  • Winterizing plugs and a skimmer plug to block up and protect the pipes and skimmer tank.
  • Pool heater and pump covers to insulate outdoor equipment.
  • Antifreeze to protect outdoor pool pipes from damage.

Note — chat with a pool care or hardware store attendant about your specific needs and product recommendations.

Step 2: Test Your Above-Ground Pool Water

Pool pH Test
Pool pH Test

Because you’ll be closing your pool for an extended period, it’s necessary to balance its water chemistry beforehand. Depending on the treatments needed, you should do this task around a week or two before shutting it up for winter.

First, test the water to see which imbalances need to be addressed.

Ideally, your:

  • pH levels should read 7.4 to 7.6 ppm

PH (potential of hydrogen) level is the measure of how alkaline or acidic a liquid, such as pool water, is. The more balanced your pool water, the more effective chemicals (such as chlorine) and treatments are when applied.

  • Total alkalinity should be 80 to 120 ppm

Total alkalinity denotes how resistant your pool water is to a change in pH levels. Ideal total alkalinity levels increase the likelihood that water pH remains balanced, should materials that usually affect it be added.

  • Calcium hardness should be 200 to 400 ppm

Calcium hardness is a measure of the number of calcium ions present in your pool water. Hard water has a higher mineral content, and soft water has less. Higher amounts of calcium and magnesium can corrode pool plumbing and cause build-up. However, water that is too soft can corrode plaster, metal, and concrete.

  • Chlorine levels should be 2.0 to 4.0 ppm (chlorinated pools), 1.0 to 3.0 ppm (salt water pools), or 0.5 to 1.0 ppm (mineral pools)

Chlorine is an essential active chemical in chlorinated, salt-water, and mineral pools. Maintaining adequate chlorine levels inhibits the growth of microorganisms like algae, bacteria, and mold.

  • Phosphate levels should be under 100 ppb

Phosphates are naturally-occurring particles originating from organic matter, like leaves, fertilizer, and the like. Because phosphates act as food for algae, you want to remove as many as possible before closing up your pool. Otherwise, algal blooms may thrive in your pool, requiring a heavy-duty clean when you open it again.

Step 3: Remove Non-Essential Pool Equipment & Toys

Swimming Pool Ladder in Snow

Before you start treating and winterizing your above-ground pool, be sure to remove all non-essential equipment. You should take out any pool toys, as well as ladders and other functional equipment. Store these items in a shed, basement, or your house over the colder months, to keep them in good condition.

Note — keep your pool cleaning equipment, such as pump, skimmer, and hoses, in place for now.

Step 4: Balance Your Water Chemistry

Swimming Pool Chemicals and Equipment

Once you know if and where any water chemical imbalances lay, tackle them accordingly. From shock treatments to stabilizers, tablets to powders, plenty of treatments are available.

Note — remember to always test your water again after you have treated it, to ensure the treatment has done its job.

Balance pH Levels:

Depending on which direction your imbalance lies in, use a dry acid or soda ash and alkali treatment to balance your pH.

Improve Total Alkalinity:

For total alkalinity issues, you can also use soda ash, alkali, or dry acid treatments — alternatively, choose specialized alkalinity-balancing products.

Treat Hard or Soft Water:

Soft water treatments mainly focus on increasing the mineral content of the water, whereas pumping and refilling your pool with some soft water is the best way to balance hard water. Installing a hard water filter is also recommended for those living in areas with a hard water supply.

Control Phosphate Levels:

Calcium is a positive ion and phosphorous is a negative ion. Maintaining optimum calcium hardness levels helps control and lower phosphate levels. You should also clean, scrub, and skim your pool regularly. Doing so minimizes the introduction of phosphates from organic matter, such as leaves and grass clippings.

Step 5: Clean Your Above-Ground Pool

Dirty Swimming Pool

No one wants to deal with green water and stains when they re-open their pool after winter. Cleaning and treating your pool is necessary before winterizing it, to reduce build-up and algae formations. That way, you can have your pool ready in time for the summer season as soon as possible.

Prevent Scale and Stain Formation:

Stains and scale can build up over winter. As such, tackling any before you winterize your above-ground pool is a good idea. Treating your pool with a scale and stain remover around two weeks before closing it up should do the job.

Note — it’s a good idea to scrub, brush, and vacuum the walls and floor of the pool to remove any existing build-up.

Manage Algae:

Balancing your pool water and cleaning it regularly generally keeps algae in check. But extra precautions are needed when winterizing your pool. Add an algaecide to ensure minimal formation, just before shock-treating. Be sure to remove algae beforehand by scrubbing, skimming, and pumping your pool.

Note — you can lift up a corner of your pool cover every now and then throughout winter, to check for algae formations. If there are any, add more algaecide to manage it.

Give Your Pool a Shock Treatment:

A pre-winterization shock treatment will kill off microorganisms hidden in the pool water. It inhibits the formation of algae, as well as bacteria and chloramines. Do one before you close up your pool to ensure it’s as free from these contaminants as possible.

Note — traditional chlorine shock treatments aren’t ideal for mineral pools. Equally, you should select suitable salt-water pool shock treatments carefully.

Step 6: Drop Your Above-Ground Pool Water Level

For winter, you want to drop your pool water level to reduce damage from ice formation. Around 3 to 6 inches below the skimmer opening — not lower — is ideal. After all, you need to protect your pool liner and interior by maintaining adequate water levels.

Note — be sure to plug up your skimmer with a skimmer plug to stop water from getting into it. Doing so reduces the likelihood of water inside freezing and expanding, and causing damage. You can also find skimmer protector plugs that minimize cold damage.

Step 7: Drain & Protect Your Hoses, Pipes & Pool Equipment

Pool Pipes and Equipment

Your above-ground pool may feature portable hoses, permanent pipes, or a mixture of both, as well as additional pumping, filtering, heating, and chlorinating equipment. You want to remove all the water from these parts to reduce the chances of water freezing inside and causing damage to the equipment.

Pool, Filter, & Skimmer Hoses:

After your skimmer plug is installed, remove the skimmer hose and drain it. Next, plug your pool return line with a suitable winterizing plug from the inside of the pool. Then disconnect the hose, drain it dry, and store both hoses safely inside, away from the elements.

Permanent/PVC Pool Pipes:

Hard PVC pipes usually cannot be removed, making them more susceptible to damage over winter. Ideally, use a wet/dry shop vac to remove as much interior water as possible. You can also add antifreeze afterwards to minimize the chances of damage, especially if ground temperatures reach below 0°C/32°F.

Note — be sure to plug all your pool pipes to ensure no water gets in during the winter. Doing so is also a must if adding antifreeze, to keep children and animals safe.

Pool Pumps, Chlorinators, Purifiers, & Filters:

Be sure to drain your pool pumps and equipment of water to protect them from damage. If you have a detachable, portable pool pump or equipment, try to keep them indoors. You also want to clean out any filter cartridges before closing up the pool for the winter.

Pool Heaters:

Shut off the power and/or gas supply to your pool heater — be it gas-fired, solar, or electric — over the winter. You can also protect your heater from the elements with a pool heater cover. If nesting mice or rats are an issue, add a few mothballs.


To prevent damage and cracking, you may want to lubricate your O-rings. A Teflon-based pool lube is best, and can be applied to any rubber O-rings on your equipment. Examples are those located on your pump lid, filter tank, and drain plug, as well as union O-rings.

Step 8: Add Your Winterizing Chemicals

Winterizing chemicals and kits are designed exclusively for maintaining pool water while your pool is closed-up. A kit should include algaecide, shock treatment, scale preventative, and a winterizing pill. If you buy a kit, follow the directions for the order in which to do each treatment.

Winterizing pills are plastic pills designed to float in the water and slowly release pool chemicals into your pool while it’s closed-up, so you don’t have to. Add your winterizing pill just before covering up your pool.

These pills generally last 6 months, and contain a specially-formulated mix of chemicals that maintains water in these unique conditions. Look for a winterizing pill with a clarifier, scale & stain inhibitors, and enzyme enhancement.

Step 9: Cover-Up Your Above-Ground Pool

Small Covered Pool

Now that all your treatments and preparations are done, it’s time to cover up your above-ground pool for winter. Place your air pillows first, and secure them, then place the cover over them. Secure the pool cover with cables and clips, then weight it, wrap the cover edges with your cover seal, and add a leaf net, if necessary.

Pool with Sagging Pool Cover
Pool with Sagging Pool Cover

Note — you should always use a specialized cover that perfectly fits the shape and size of your pool. Tarps and other non-official equipment may not provide adequate cover, support, or insulation, leading to damage.

Step 10: Switch off Your Electricals & Water Supply

Once your pool is all wrapped up and ready for winter, make sure you switch off the electricals and water supply. If you’re heading out on vacation or a family holiday, doing so is critical. You don’t want any unexpected leaks, fires, or burn-outs to spoil your fun. You should switch off the power at the circuit breaker and on the GFCI outlet body.

To Conclude

Winterizing an above-ground pool is a necessity to protect it from the elements, especially in colder climes. Doing so will ensure it doesn’t get damaged, and that it will be as near to ready to swim in when spring and summer arrive. The tips mentioned above should help make the process easy, and ensure you don’t forget any vital tasks, of course.

Caitlin Greyling

Caitlin Greyling is a professional writer and editor with a fine art, design, and photography background — focusing on sustainability, climate change, equality, travel, tech, culture, and societal issues. She’s currently studying journalism with the NCTJ and has written for The Daily Mail, Durability Matters, CNN, PictureCorrect, Pilot Plans, and more.

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