How To Close Above Ground Pool For Winter: The Ultimate Step-by-Step Guide
Closing your above ground pool properly prevents structural damage, protects liner integrity, and stops algae proliferation before freezing temperatures arrive. By balancing water chemistry, lowering the water table precisely, and installing a heavy-duty winter cover, you ensure a clear, easy opening when spring returns.
Pre-Operation and Equipment Checklist
Successfully winterizing an above ground swimming pool requires proper preparation, specific chemical treatments, and the right gear to withstand harsh weather conditions. Rushing this process or using unrated equipment can lead to torn liners, frozen plumbing lines, and expensive spring repairs.
- Essential Gear and Tools: Winter cover, heavy-duty winch and cable, leaf net, pool pillow, pool antifreeze, air compressor or shop vac, water test kit, garden hose, and skimmer plug plate.
- Mandatory Chemicals: Closing chemical kit (shock, algaecide, metal sequestrant), pH increaser/decreaser, and alkalinity increaser.
- Prerequisite Standards: Complete the closing process only when water temperatures consistently drop below 65 degrees Fahrenheit (18 degrees Celsius) to prevent algae growth under the cover.
- Estimated Budget and Duration: Expect to spend between $100 and $300 on chemicals and replacement accessories, with a total labor time of 3 to 5 hours.
Step-by-Step Above Ground Pool Winterization Workflow
Step 1: Deep Clean and Clear Debris
Begin by removing all ladders, solar blankets, skimmer baskets, and wall accessories from the pool. Skim the surface thoroughly, brush the walls to dislodge microscopic debris, and vacuum the floor meticulously. Any organic matter left in the water will decompose over the winter, staining your liner and consuming your winterizing chemicals.
Pro-Tip: Vacuum to waste if your pool has heavy sediment or leaves. This ejects dirty water directly out of the system rather than passing it through your filter media.
Step 2: Balance Water Chemistry
Test your pool water and adjust the chemical parameters into strict winter ranges to protect your liner and pool walls. Set the pH between 7.2 and 7.6, total alkalinity between 80 and 120 ppm, and calcium hardness between 175 and 225 ppm. Add a heavy-duty metal sequestrant if you have well water to prevent iron and copper staining during the off-season.
Step 3: Apply Winterizing Chemicals and Shock
Broadcast a non-chlorine shock or a specialized winterizing shock across the pool surface with the pump running. Wait approximately four to six hours, then add a high-quality, long-lasting copper-based or non-metallic algaecide. Run your filtration system continuously for 24 hours to circulate these chemicals evenly throughout the entire body of water.
Step 4: Lower the Water Level
Lower the water level below the skimmer and return jet to prevent freezing water from cracking the pool walls or skimmer housing. For standard vinyl liner above ground pools, lower the water level approximately 4 to 6 inches below the skimmer faceplate. Never drain an above ground pool completely; hydrostatic pressure from surrounding frozen ground can cause the liner to shrink, pull away, or collapse the pool walls.
Warning: Never empty your above ground pool entirely for winter. Without internal water pressure to counteract the weight of shifting frozen ground, the pool structure will fail.
Step 5: Blow Out and Plug Plumbing Lines
Disconnect your above ground pool pump, filter system, and chlorinator, draining all residual water from the housing tanks. Use a shop vacuum or air compressor to blow out any water trapped inside the return lines and hoses. Once cleared, insert heavy-duty rubber expansion plugs into the return fittings and secure a skimmer cover plate over the mouth of the skimmer to keep rainwater and melting snow out.
Step 6: Install the Air Pillow and Winter Cover
Inflate an air pillow to roughly 60 to 70 percent capacity and place it directly in the center of the pool using the integrated grommets and nylon strings anchored to the top rails. The air pillow absorbs the expansion pressure of freezing ice, protecting your pool walls from inward stress. Finally, drape your solid winter cover over the pool, thread the heavy-duty cable through the eyelets, and tighten it securely with the winch.
How To Winterize An Above Ground Swimming Pool | Storables
Technical Specifications and Chemical Dosages
| Parameter / Chemical | Ideal Winter Target | Purpose / Function | Failure Consequence |
|---|---|---|---|
| pH Level | 7.2 to 7.6 | Prevents chemical imbalances from etching metal or scaling liner. | Liner staining, wrinkling, or corrosion of metallic pool components. |
| Total Alkalinity | 80 to 120 ppm | Acts as a pH buffer to stabilize water chemistry over winter. | Rapid pH fluctuations and severe equipment degradation. |
| Water Level | 4 to 6 inches below skimmer | Keeps water safely away from freezing zones without risking structural collapse. | Cracked skimmer housings or collapsed pool walls. |
| Algaecide Dose | Product specific (usually 2-4 oz per 10k gal) | Kills existing spores and prevents winter algae blooms. | Opening to a green, swampy pool filled with organic sludge. |
Common Site Failures and Field Fixes
- Root Cause: The winter cover collapses into the pool during a heavy snowstorm or high winds.
- Actionable Fix: Ensure your cover cable is tightened securely with a winch and use water tubes or cover clips if necessary. Check that your air pillow is properly inflated and centered using anchor strings.
- Root Cause: Water freezes inside the return lines or skimmer, cracking the plastic housing.
- Actionable Fix: Always use a shop vac to blow out all lines completely until no mist or moisture exits. Apply non-toxic pool antifreeze inside the lines and seal them tightly with expansion plugs and a skimmer ice protector.
- Root Cause: Opening the pool in spring reveals thick, green algae growth and staining.
- Actionable Fix: You likely added winter chemicals too early while water temperatures were still above 65 degrees Fahrenheit, causing the chlorine to dissipate. Shock the pool aggressively upon opening and use a flocculant to drop debris to the floor for vacuuming.
Frequently Asked Questions
When is the best time to close my above ground pool?
You should close your pool when daytime ambient temperatures consistently drop below 65 degrees Fahrenheit and nighttime temperatures approach freezing. Closing too early allows algae to multiply rapidly in warm, untreated water, while closing too late risks sudden freezing pipes.
Do I need to drain my above ground pool for the winter?
No, you should never drain an above ground pool for the winter. The water inside acts as a stabilizing weight against ground pressure and protects your vinyl liner from drying out, cracking, and shrinking. Simply lower the water level slightly below the skimmer level.
Can I use a regular tarp instead of a winter cover?
While standard blue tarps are inexpensive, they lack UV protection, tear easily under snow loads, and rarely last more than one season. Investing in a woven, heavy-duty polyethylene winter cover with reinforced seams saves money and frustration over time.
How do I keep my pool cover from blowing away in winter?
Secure your winter cover by threading the included steel cable through the perimeter eyelets and tightening it firmly with the winch. You can also wrap a pool cover wrap or strap around the entire circumference of the top rails to prevent severe wind uplift.
Secure Your Pool for a Hassle-Free Spring Opening
Properly executing these winterization steps safeguards your investment and guarantees crystal-clear water when swimming season returns. Take time to winterize your pool meticulously today, and you will enjoy a seamless opening tomorrow.
