5 Tips for Winterizing Your Above Ground Pool

Closing an above ground pool for the winter looks simple on the surface. You clean it, put a cover on, and walk away. In practice, the difference between a clean spring opening and a green, debris-filled mess almost always comes down to a few details that get rushed or skipped.

 

Leaves left in the water become food for algae. A cover that isn’t sized or tensioned properly lets light and debris in for months. Equipment left with water inside can crack when temperatures drop. These five tips focus on the steps that actually prevent those problems. Follow them in order and you’ll spend far less time and money when swimming season starts again.

 

 

1. Clean the Pool Thoroughly Before Closing

This is the step most people are tempted to hurry. The weather is turning, the swimming season feels over, and the idea of a full clean feels like extra work. But whatever remains in the water when the cover goes on will sit there for the entire closed season.

 

Leaves, insects, pollen, and sediment break down over time. That organic material becomes a food source for algae. Debris that settles against the liner can also cause staining that is hard to remove later. Cleaning first removes both the food source and the staining risk.

 

Do a complete clean:

1. Skim the surface until it is free of floating leaves, twigs, and insects.

2. Brush the walls and floor thoroughly. Pay extra attention to corners and areas with low circulation.

3. Vacuum the bottom carefully so sediment does not get stirred back into the water.

4. Empty and rinse the skimmer basket.

 

If the pool has been sitting for a while with noticeable debris, consider running the filter for a few hours after cleaning to polish the water before you balance chemicals. A clean pool at closing is one of the strongest predictors of how clean it will be when you open.

 

Once the cover is installed, you cannot easily reach what is underneath. Taking the time now prevents a much larger job later.

 

 

2. Balance the Water and Add Winter Chemicals

Water chemistry does not stop mattering just because the pool is closed. Unbalanced water is more likely to develop scale on surfaces, stain the liner, or support algae growth even under a cover. Taking the time to test and adjust before closing is one of the higher-return steps in the process.

 

Test and adjust these key levels:

• pH — target roughly 7.2 to 7.6. High pH reduces sanitizer effectiveness and can contribute to scaling.

• Total alkalinity — most pools do well in the 80 to 120 ppm range. Alkalinity stabilizes pH.

• Sanitizer — raise free chlorine with a shock treatment if levels are low. You want a residual that will hold for the closed period.

• Calcium hardness — stay within the range recommended by your liner manufacturer. Very high or very low hardness can cause problems over months of still water.

 

Many owners also add a winterizing algaecide formulated for closed pools. If you have hard water or a history of metal stains, a metal sequestrant can help keep metals in solution so they do not deposit on the liner. Follow the product directions for your exact pool volume and give the chemicals time to circulate fully before you put the cover on.

 

Skipping chemistry is one of the more common reasons a covered pool still opens cloudy or green. The cover blocks light and debris, but it does not correct water that was already out of balance.

 

3. Protect the Pump, Filter, and Plumbing

Equipment left with water inside is a frequent source of spring repair bills. When water freezes it expands. That expansion can crack pump housings, split filter tanks, and damage fittings. Taking a short time to drain and protect the system prevents those failures.

 

Work through these steps:

1. Remove the ladder and any accessories that sit on or above the top rail. Sharp edges and protruding hardware can puncture or abrade the cover over months of contact.

2. Drain the pump and filter completely. Open drain plugs and run the system dry according to the manufacturer’s guidance.

3. Store the pump and filter indoors if you have space. Indoor storage removes freeze risk entirely and keeps the equipment cleaner.

4. In colder climates, blow out the lines or drain them according to local freeze risk. Even a small amount of trapped water can cause damage in a hard freeze.

 

If you live in a mild climate the freeze risk is lower, but draining the equipment is still good practice. It costs almost nothing and eliminates one of the more expensive potential problems. Leaving the ladder in place is another common mistake — it creates a contact point that can damage the cover and also makes the pool harder to secure.

 

Treat this step as insurance. A few minutes of draining and storage is far cheaper than replacing a cracked pump or filter in the spring.

 

 

4. Install an Air Pillow and a Solid Cover

This is the step that carries most of the load over the winter. A solid cover blocks sunlight — the primary driver of algae growth — and keeps the bulk of leaves and debris on top of the fabric instead of in the water. An air pillow helps the cover shed rain and snow so weight does not collect in the center and stretch the material.

 

Start with the air pillow. Place it in the center of the pool and inflate it enough to create a gentle dome. The goal is support, not maximum pressure. Over-inflating can put unnecessary stress on the cover. Check the pillow once or twice during the winter if you can reach it; some air loss over months is normal.

 

Next, install the solid cover. Measure the outer rail of the pool — the outside edge of the top metal frame — not the water surface or the liner. Covers are manufactured larger than the listed pool size so they have proper overlap. An undersized cover leaves gaps; an oversized one flaps and stresses the seams.

 

Installation sequence:

1. Center the cover over the pool so the overhang is even all the way around.

2. Drape it carefully over the top rail.

3. Engage all the ratchet straps or thread the continuous cable through the loops or grommets.

4. Tighten gradually around the full perimeter. Work your way around the pool rather than fully tightening one section and then another.

5. Walk the entire rail and correct any soft or loose spots. The finished cover should feel firm and even, similar to a drum.

 

Correct size and even tension matter more than almost any other factor. Full measuring guidance is here: The Ultimate Above Ground Pool Cover Size & Material Guide.

Detailed installation steps for both ratchet-strap and cable systems are here: How to Install an Above Ground Pool Cover Correctly.

Solid covers generally outperform mesh for winter use because they block more light. Side-by-side comparison is here: Solid vs Mesh Above Ground Pool Covers.

Current solid covers with ratchet or cable systems are available here: All Above Ground Pool Covers. Round sizes are also listed separately: Round Above Ground Pool Covers.

 

 

 

5. Check the Cover During the Winter

Installing the cover is not the final step. A solid cover still needs occasional attention through the closed season. Standing water stretches the fabric over time. Heavy leaf loads pull sections out of position and create uneven stress. Wind can gradually loosen tension, especially if the cover was not fully even to begin with.

 

Make these checks part of a light winter routine:

1. After significant rain or snow, pump off standing water. A cover pump makes this quick. Continuous water weight is one of the faster ways to stretch and weaken fabric.

2. Clear large piles of leaves so the load stays distributed. Dry leaves can often be blown or brushed off; wet leaves are easier to scoop with a leaf rake.

3. After major wind events, walk the perimeter and re-tighten any sections that have loosened. A cover that starts tight can settle or shift.

 

These simple habits prevent many of the failures that shorten cover life. More detailed care guidance is here: How to Maintain an Above Ground Pool Cover.

 

If you want the entire closing process in checklist form, use this: The Complete Above Ground Pool Closing Checklist.

 

For context on what happens when a pool is left uncovered, see: What Happens If You Don’t Cover Your Above Ground Pool for Winter?.

 

 

Putting the Five Tips Together

The most effective winterizing sequence is simply these five steps in order:

• Clean the pool thoroughly

• Balance the water and add winter chemicals

• Protect the pump, filter, and plumbing, and remove the ladder

• Install an air pillow and a correctly sized solid cover with even tension

• Check the cover periodically through the winter

 

None of the individual steps is difficult. The problems arise when they are done out of order or when one of them is skipped because the weather is turning or time is short. A solid cover only performs as well as the preparation underneath it and the tension that holds it in place.

 

 

Bottom Line

Winterizing an above ground pool is not complicated, but it is sequential. Clean first so debris is not trapped under the cover. Balance the water so chemistry problems do not develop over months of still conditions. Protect the equipment so freeze damage does not create spring repair costs. Install a solid cover that is sized to the outer rail and tensioned evenly, with an air pillow to manage water and snow load. Then give the cover occasional attention through the closed season.

 

The cover is the element that works hardest for the longest period. Taking the time to choose the right size, install it correctly, and keep it free of standing water is one of the highest-return actions you can take at closing. Done properly, it turns spring opening from a major project into a much more manageable task.

 

Ready to select a solid cover? Browse current sizes and fastening systems here: All Above Ground Pool Covers.