How To Close Above Ground Pool For Winter
Properly winterizing an above ground pool requires balancing water chemistry, lowering the water level below the skimmer, and installing a heavy-duty winter cover to prevent structural damage from freezing temperatures and ice expansion. Neglecting these critical steps can result in ripped vinyl liners, cracked pool walls, and severe algae blooms that complicate spring startup.
Pre-Winter Preparation & Equipment Checklist
Closing an above ground pool successfully requires a methodical approach and specific technical gear to protect your investment during freezing months. Proper water balancing must occur three to five days before winterization to allow chemicals to distribute evenly without bleaching the vinyl liner.
- Essential Gear and Tools: Telescopic pole, wall brush, pool vacuum, heavy-duty winter cover, winch and cable assembly, air pillow or ice compensator, pool closing kit (winter algaecide, shock, and sequestering agent), skimmer cover plate, and non-toxic propylene glycol antifreeze.
- Mandatory Standards: Ambient air temperatures should consistently remain below 65 degrees Fahrenheit (18 degrees Celsius) before closing the pool to prevent algae proliferation under the cover. Water chemistry parameters must fall within strict ranges: pH between 7.2 and 7.6, total alkalinity between 80 and 120 ppm, and calcium hardness between 175 and 225 ppm.
- Budget and Duration Benchmarks: The physical closing process typically takes between three to five hours of active labor. Material costs for chemicals, covers, and plugs generally range from one hundred to three hundred dollars, depending on pool dimensions and regional climate severity.
Step-by-Step Above Ground Pool Winterization Process
Step 1: Deep Cleaning and Debris Removal
Begin by thoroughly cleaning the pool to remove all organic matter, leaves, and sediment that could stain the vinyl liner or fuel organic growth over the winter. Scrub the pool walls and floor using a nylon-bristled brush, then vacuum the entire pool floor to waste if your system allows, ensuring no debris remains. Remove all ladders, deck stairs, pool toys, and solar blankets from the pool area, cleaning and drying them thoroughly before storing them in a shed or garage.
Pro-Tip: Vacuuming to waste prevents organic debris from clogging your filter media or returning to the pool, ensuring a pristine environment for chemical treatment.
Step 2: Water Balancing and Shock Treatment
Test the pool water with a reliable liquid test kit or digital photometer and adjust the pH, total alkalinity, and calcium hardness to their optimal ranges. Broadcast a non-chlorine shock or a specialized winterizing shock across the surface of the pool with the pump running continuously for at least 24 hours to ensure thorough mixing. Add a long-lasting, copper-free winter algaecide according to the manufacturer dosage instructions to prevent microscopic organism growth during the dormant months.
Step 3: Lowering the Water Level and Draining Equipment
Lower the water level in the above ground pool based on your specific winter cover configuration and drainage guidelines. For standard winter covers that allow water to pass through, drop the water level to approximately 4 to 6 inches below the skimmer return line. If you are using a solid, water-proof safety cover, lower the water level to roughly 12 to 18 inches below the skimmer. Disconnect the hoses connecting the pool to the pump, filter, and chlorinator, ensuring every drop of water is drained from the equipment.
Warning: Never drain an above ground pool completely for the winter; the hydrostatic pressure of surrounding groundwater can cause the vinyl liner to shrink and the pool walls to collapse inward.
Step 4: Protecting Plumbing Lines and Skimmers
Blow out all return lines using a shop vacuum or air compressor to force any remaining water out of the PVC or flexible hoses. Plug the return jets tightly with threaded winter expansion plugs featuring rubber gaskets to form an airtight and watertight seal. Install a Gizzmo ice preventer or skimmer bottle into the skimmer housing to absorb the lateral expansion pressure of freezing water, and seal the skimmer faceplate with a dedicated winter cover plate if required by your setup.
Step 5: Installing the Air Pillow and Winter Cover
Inflate a heavy-duty vinyl air pillow to approximately 60 to 70 percent capacity and secure it directly in the exact center of the pool using nylon tether cords tied to the top ledges. Center the winter cover over the pool, pulling the excess material evenly over the pool wall perimeter. Thread the heavy-duty vinyl-coated steel cable through the grommets of the cover, feed it through the ratchet mechanism, and crank it tightly to secure the cover against wind uplift.
Easiest Way To Close Above Ground Pool at Helen Shields blog
Above Ground Pool Winterization Method Comparison
| Parameter / Method | Standard Mesh Winter Cover | Solid Vinyl Safety Cover | Air Pillow vs. No Pillow |
|---|---|---|---|
| Water Level Target | 4 to 6 inches below skimmer | 12 to 18 inches below skimmer | Center placement under cover |
| Debris Filtration | Lets rainwater in; blocks solid debris | Blocks all water and debris | Disperses ice expansion forces |
| Spring Cleanup Effort | Moderate to high due to fine silt | Low; water remains clear | Prevents top-rail ice damage |
| Expected Lifespan | 3 to 5 seasons | 7 to 10 seasons | 1 to 2 seasons |
Common Winterization Failures and Field Fixes
- Root Cause: The winter cover collapses into the pool under the weight of accumulated snow and rainwater.
- Actionable Fix: Inspect the air pillow to ensure it is properly inflated and centrally anchored. Pump standing water off the top of the cover using a submersible pool cover pump immediately after major storms.
- Root Cause: Water leaks past the return plug and freezes inside the return line, causing structural cracking.
- Actionable Fix: Remove the plug, inspect the rubber gasket for dry rot or cracking, apply thread sealant tape, and reinstall the expansion plug securely using a wrench.
- Root Cause: Severe algae blooms develop beneath the cover despite winterizing chemicals.
- Actionable Fix: Add an extra dose of concentrated, non-foaming winter algaecide mid-winter if unseasonably warm weather occurs, or pull back a corner of the cover to shock the water manually.
Frequently Asked Questions
Do I need to drain my above ground pool completely for the winter?
No, you should never drain an above ground pool completely. The water inside provides essential structural weight that counteracts outward soil pressure and prevents the vinyl liner from shrinking, cracking, or pulling away from the top coping.
When is the ideal time to close an above ground pool?
You should close your pool when the water temperature consistently drops below 65 degrees Fahrenheit (18 degrees Celsius). Closing too early while the water is still warm allows algae to consume the sanitizer and multiply rapidly.
How do I keep rain and snow off my winter cover?
Use an electric or manual submersible cover pump to remove accumulated water from the top of the cover every few weeks. Keeping excess weight off the cover prevents premature stretching and protects your pool structure from undue stress.
Can I use regular indoor antifreeze in my pool plumbing lines?
Never use automotive antifreeze, as it is toxic and contains chemicals that can ruin your pool liner and pose health hazards. Always use certified, non-toxic propylene glycol antifreeze rated specifically for swimming pool plumbing.
Protect your pool investment this winter with premium-grade closing supplies and expert care to guarantee a crystal-clear swimming environment next season. Browse our comprehensive inventory of winter covers, expansion plugs, and algaecides to secure your pool today.
