How to Winterize an Above Ground Pool: A Complete Cold-Weather Shutdown Guide

Winters are a beautiful present from the nature. You can have lots of memories in winters that may or not be soothing to you but they can last forever.

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Your summer memories may still be floating in that crystal-clear water, but once the temperatures drop, your above ground pool needs more than a fond farewell—it needs protection. If you skip this crucial step, you’re inviting algae blooms, liner damage, cracked plumbing, and an expensive cleanup next spring. That’s why every pool owner must know how to winterize an above ground pool the right way.

Winterizing isn’t just about covering your pool. It’s a multi-step process that secures your equipment, balances your water, and shields your investment from harsh winter conditions. Whether you’re a first-time pool owner or just need a yearly refresher, this guide will walk you through everything you need to do before the frost arrives.

Step-by-Step: How to Winterize an Above Ground Pool

1. Clean the Pool Thoroughly

Start by removing all debris—leaves, bugs, and dirt. Use a pool vacuum to clean the bottom and walls, then skim the surface. Any organic matter left behind can rot over the winter and cause staining or algae issues.

Brush the walls and floor
Vacuum sediment thoroughly
Empty skimmer baskets and filter baskets

2. Balance the Water Chemistry

Before you even think about draining or covering, balance the water chemistry. This helps protect the liner and equipment while minimizing algae growth.

Ideal winterizing levels:

pH: 7.4–7.6
Alkalinity: 100–150 ppm
Calcium Hardness: 175–250 ppm
Chlorine: 1–3 ppm

Use a reliable test kit and adjust as needed. It’s essential to do this 24–48 hours before adding winterizing chemicals.

3. Add Winterizing Chemicals

You’ll need:

Shock treatment: Kills remaining contaminants
Algaecide: Prevents green growth during dormancy
Stain & scale preventer: Protects surfaces and equipment
Winter pill or floater (optional): Offers ongoing chemical release

Follow the product instructions closely and let the pump circulate the chemicals for several hours afterward.

4. Lower the Water Level (But Don’t Drain It All)

Drain water to about 4–6 inches below the skimmer opening. This prevents freezing water from cracking your skimmer or return lines. Avoid draining the pool completely—this can cause liner shrinkage and structural damage.

If your pool has a return jet, remove the fitting and insert a winter plug.

5. Remove and Store Pool Equipment

Disconnect and thoroughly drain:

Hoses
Pump
Filter
Ladders and rails
Skimmer basket and eyeball fitting

Allow all equipment to dry, then store it in a dry, protected space like a garage or shed to prevent cracking or mildew during the winter.

6. Install an Air Pillow

Place an air pillow in the center of the pool before covering it. This device:

Absorbs the pressure of expanding ice
Prevents damage to the pool walls
Keeps the cover elevated to prevent water and debris accumulation

Tie the pillow to opposite sides of the pool so it stays centered.

7. Cover the Pool Securely

Use a heavy-duty winter cover designed for above ground pools. Make sure it’s tightly secured with a cable and winch system or cover clips.

Check that:

The cover is snug and not sagging
The air pillow stays centered
No gaps allow debris to enter

8. Monitor Periodically Throughout Winter

Even when winterized, your pool needs occasional checks:

Remove snow or standing water from the cover
Inspect the cover for tears or sagging
Make sure the air pillow hasn’t deflated

A quick check once or twice a month can prevent a small issue from becoming a spring disaster.

Common Winterizing Mistakes to Avoid

Leaving toys in the pool: They can trap bacteria or damage the liner.
Using a regular tarp as a cover: Not secure, not breathable, and tears easily.
Skipping chemical balance: You’ll regret it when algae and scale take over.

Final Thoughts

Now that you know how to winterize an above ground pool, there’s no excuse to leave it at the mercy of freezing temperatures and weather damage. Proper winterization might take a little time and effort up front, but it can save you hundreds of dollars—and a major headache—when pool season rolls around again.

Treat your pool right in the off-season, and it will return the favor when summer shines again. Winter-proof now, relax later.