How To Close A Pool Above Ground: The Complete Step-by-Step Winterization Guide
Closing your above ground pool correctly prevents freezing damage to structural components, stops algae blooms before spring, and protects your investment through harsh winter months. This comprehensive process requires balancing water chemistry, lowering water levels below the return jet, draining sensitive equipment, and installing a heavy-duty winter cover.
Essential Preparation and Winterization Equipment Checklist
Proper winterization demands specific tools, hardware, and chemicals to withstand freeze-thaw cycles without compromising your pool's structural integrity. Neglecting foundational preparation often leads to split vinyl liners, cracked PVC lines, and rusted metallic walls.
- Essential Gear & Tools: Pool pillow (for air compression relief), heavy-duty winter cover, winch and cable kit, heavy-duty cover seal or wrap, gizzmo ice compensator/expansion plug, plumber's tape, water pump, and leaf skimmer.
- Water Chemistry Balancers: Granular shock (non-chlorine or calcium hypochlorite), winterizing algaecide (long-lasting copper-free formula), metal sequestrant, pH increaser/reducer, and total alkalinity buffer.
- Prerequisite Standards: Complete winterization should occur when consistent water temperatures drop below 65°F (18°C) to prevent algae reproduction. Never drain an above ground pool completely, as hydrostatic pressure or shifting ground will ruin the vinyl liner.
- Time and Budget Investment: Expect to spend 3 to 5 hours completing the process. Material and chemical costs range from $100 to $300 depending on pool volume (typically ranging from 10,000 to 24,000 gallons).
Step-by-Step Above Ground Pool Winterization Workflow
Step 1: Deep Clean and Balance Water Chemistry
Begin by removing all organic debris, leaves, and sediment using a pool vacuum and leaf net. Scrub the pool walls with a soft-bristle brush designed for vinyl liners to dislodge micro-algae spores. Test the water parameters and adjust total alkalinity to between 80 and 120 ppm, and maintain pH levels strictly between 7.2 and 7.6. Add a specialized winterizing algaecide and a non-chlorine shock according to your pool's exact gallon capacity, running the filtration system continuously for 24 hours to distribute chemicals evenly.
Pro-Tip: Balance your water chemistry at least a week before closing to allow chemicals to dissolve fully without bleaching the vinyl liner.
Step 2: Lower the Water Level and Protect Plumbing Lines
Lower the water level using a submersible pump or your filter's waste setting. For standard above ground pools, drop the water level to approximately 4 to 6 inches below the return jet and skimmer mouth.
Warning: Never empty an above ground pool below 12 inches of water, as extreme ground freezing or wind forces can cause the unsupported walls to collapse inward.
Step 3: Drain and Store Filtration Equipment
Disconnect all flexible hoses connecting the skimmer, pump, and filter system. Remove the drain plug at the bottom of the filter tank and pump housing to evacuate trapped water completely. Store the pump, motor, and salt chlorine generator cell indoors in a frost-free environment like a basement or garage. Bring inside any directional fittings, pressure gauges, and hoses to prevent freezing expansion cracks.
Step 4: Plug Return Lines and Skimmers
Clean the skimmer housing thoroughly and insert a skimmer guard or specialized gizzmo expansion plug into the bottom skimmer port to absorb ice expansion pressure. Plug the return jet tightly from the inside using a threaded winter plug wrapped in plumber's tape. If your pool utilizes an above ground main drain, blow out the line with a wet/dry shop vacuum and seal it with a rubber expansion plug.
Step 5: Inflate and Secure the Winter Pool Pillow
Inflate a heavy-duty vinyl air pillow to roughly 60 or 70 percent capacity—never over-inflate, as ice pressure will burst it. Position the pillow directly in the center of the pool surface, tying it securely with nylon ropes to opposite top rails of the pool frame so it cannot drift to the edges. The pillow absorbs inward ice expansion, protecting the pool walls from outward pressure.
Step 6: Install and Fasten the Winter Cover
Drape the solid winter cover evenly over the entire pool surface and center air pillow. Secure the perimeter using the included cable and winch threaded through the grommets along the pool cover hem.
Pro-Tip: Wrap a heavy-duty cover wrap or winter seal band around the perimeter of the top rails to lock the cover down and prevent wind whip from tearing the material during winter storms.
How To Close An Intex Above-Ground Pool For The Winter — Peony Street
Above Ground Pool Winterization Chemical and Hardware Matrix
| Component / Parameter | Recommended Target Range / Material | Function / Purpose |
|---|---|---|
| pH Level | 7.2 – 7.6 | Prevents metal corrosion and scale buildup on pool surfaces. |
| Total Alkalinity | 80 – 120 ppm | Acts as a pH buffer against sudden chemical swings. |
| Winter Algaecide | Non-metallic, long-lasting formula | Inhibits algae growth when water temperatures fall. |
| Water Level | 4 to 6 inches below return jet | Protects skimmer and return housing from ice freeze. |
| Air Pillow | Heavy-duty vinyl (60-70% inflation) | Relieves ice expansion pressure against pool walls. |
Common Winterization Failures and Field Fixes
- Root Cause: Cover sinking into the pool during heavy snow or rainstorms.Actionable Fix: Pump standing water off the cover immediately using a cover pump. Inspect the air pillow; if deflated, replace or reinflate it to 70% capacity and re-secure the tie ropes.
- Root Cause: Green water and severe algae growth discovered upon spring opening.Actionable Fix: The winter algaecide degraded prematurely or chemicals were unbalanced during closing. Shock the pool immediately upon opening with a double dose of chlorine shock, run the filter 24/7, and brush daily until clear.
- Root Cause: Cracked return fitting or split skimmer housing.Actionable Fix: Trapped water froze inside the rigid plastic components. Replace the damaged housing, ensure all lines are completely blown out or plugged, and lower the water level further below the plumbing line next season.
- Root Cause: Vinyl liner pulling away from the top track or tearing under wind stress.Actionable Fix: The winter cover was fitted too loosely, allowing wind to catch the underside. Tighten the perimeter cable and winch securely, and apply cover clips or a wrap to lock the material down.
Frequently Asked Questions
Can I leave my above ground pool pump outside all winter?
No, leaving a pump outside filled with water will result in freezing, cracking of the volute casing, and motor burnout. Always disconnect the pump, drain all internal water, and store it in a dry, temperature-controlled indoor location.
How low should I drain my above ground pool for winter?
You should lower the water level strictly to 4 to 6 inches below the return jet and skimmer mouth. Never drain the pool completely, as the remaining water weight is required to anchor the vinyl liner against the structural walls.
Do I really need an air pillow under my winter cover?
Yes, an air pillow is critical for above ground pools because it floats in the center and absorbs the crushing pressure of freezing ice. Without it, expanding ice expands outward, warping metal walls and stressing the vinyl liner seams.
When is the ideal time to close an above ground pool?
The ideal time to close your pool is in autumn when water temperatures drop consistently below 65°F (18°C). Closing too early while water is warm invites algae growth, while closing too late risks sudden overnight freezes damaging your plumbing.
What is the purpose of a gizzmo plug?
A gizzmo plug is a hollow plastic pipe threaded into the bottom of the skimmer that acts as an ice compensator. It absorbs the lateral expansion pressure of freezing water, preventing the plastic skimmer housing from cracking.
Protect your pool investment this season by sourcing professional-grade winterization supplies and adhering strictly to chemical balancing standards.
