How To Close My Above Ground Pool: The Complete Winterization Guide
Closing your above ground pool correctly prevents algae growth, protects pool walls from freeze damage, and ensures clear water when spring arrives. By balancing chemistry, lowering water levels strategically based on your wall type, and installing a heavy-duty winter cover, you safeguard your backyard investment through freezing temperatures.
Pre-Winterization Assessment and Equipment Checklist
Proper seasonal shutdown requires methodical planning, precise chemical adjustments, and specialized hardware to withstand harsh winter conditions. Skipping prep steps often results in stained liners, cracked return fittings, or mosquito-infested green water by April. Gather your equipment before touching the water supply valves or pool pump system to ensure an uninterrupted workflow.
- Essential Equipment and Tools: Heavy-duty winter pool cover, winch and cable assembly, air compressor or shop vac, winterizing plug set, skimmer ice compensator (Gizzmo), non-toxic propylene glycol antifreeze, telescoping pole, and pool leaf net.
- Chemical Arsenal: Granular shock (calcium hypochlorite or non-chlorine), winterizing algaecide (long-lasting copper-free formula), metal sequestrant, and water balancing agents (pH increaser/decreaser, total alkalinity increaser, calcium hardness booster).
- Prerequisite Knowledge and Standards: Water temperature must consistently stay below 65°F (18°C) before closing to prevent organic growth from reproducing. Standard closing duration spans 3 to 5 hours depending on pool volume and equipment complexity.
Step-by-Step Above Ground Pool Winterization Process
Step 1: Deep Clean and Balance Water Chemistry
Begin your closing protocol by removing all organic debris from the pool floor using a manual vacuum and skimming the surface thoroughly. Balance your water chemistry within strict parameters: pH between 7.2 and 7.6, total alkalinity between 80 and 120 ppm, and calcium hardness between 175 and 250 ppm. Add a strong dose of winter algaecide and a metal sequestrant to prevent mineral staining on your vinyl liner during the off-season. Run your filtration system continuously for 24 hours to circulate these chemicals evenly throughout the entire water volume.
Pro-Tip: Never skip the metal sequestrant if you fill your pool from a well source, as dropping chlorine levels over winter cause dissolved iron and copper to oxidize and permanently stain your liner walls.
Step 2: Lower Water Level Safely
Adjust your water level based on your specific skimmer and return configuration to prevent freeze damage to the pool structure. For standard through-the-wall skimmers, lower the water level approximately 3 to 6 inches below the skimmer mouth using a submersible pump or your filter system's waste setting.
Warning: Never drain an above ground pool completely. Leaving less than 12 inches of water in an above ground pool during winter destroys the structural integrity of the vinyl liner, causes wall panels to buckle, and risks total pool collapse under heavy snow loads.
Step 3: Blow Out Lines and Install Winter Plugs
Disconnect the hoses running between your pool, pump, and filter system to prevent trapped water from freezing and cracking the plastic housings. Use a shop vac or air compressor to force remaining water out of the return line and skimmer line. Once cleared, insert threaded winter expansion plugs into the return fittings inside the pool. Screw a heavy-duty plastic Gizzmo ice compensator into the bottom of the skimmer to absorb the crushing pressure of freezing ice expansion.
Step 4: Disconnect Equipment and Store Indoors
Drain all remaining water from your pool pump, filter tank, and chlorinator by removing their respective drain plugs. Store your sand, DE, or cartridge filter elements, pump motor, and hoses in a dry, frost-free shed or basement to protect delicate seals, gaskets, and plastic manifolds from sub-zero cracking. Lubricate the pump lid O-rings with a silicone-based lubricant before storing them away.
Step 5: Secure the Winter Cover and Winch
Center your winter cover securely over the top rails of the above ground pool, ensuring equal overhang on all sides. Thread the provided steel cable through the eyelets or loops around the perimeter of the cover. Attach the cable to the mechanical winch, pull it taut, and lock it down to secure the cover against high winds.
Pro-Tip: Install an air pillow directly in the center of the pool underneath the winter cover. This disperses ice expansion outward toward the pool walls rather than inward against the liner and prevents heavy rainwater from pooling in the center.
Before and after of my above ground pool project | Above ground pool ...
Technical Comparison of Above Ground Pool Closing Methods
| Feature/Method | Standard Skimmer Drop Method | Complete System Blowout Method | Air Pillow Flotation Method |
|---|---|---|---|
| Water Level Adjustment | 3 to 6 inches below skimmer | 6 to 12 inches below return | Maintained at standard winter depth |
| Primary Equipment Protection | Gizzmo ice compensator | Threaded expansion plugs | Central air pillow load buffer |
| Labor Intensity | Moderate (Requires draining & plugging) | High (Requires compressed air) | Low (Focuses on cover management) |
| Ideal Climate Region | Mild to Moderate Winter Zones | Severe Freeze/Sub-Zero Zones | Universal Application |
Common Site Failures and Field Fixes
- Root Cause: Cover collapses into the pool center due to melted snow and heavy rain accumulation.
- Actionable Fix: Pump standing water off the top of the cover immediately using a cover pump. Inflate the central air pillow to 80% capacity and ensure the perimeter cable is winched tightly against the upright posts.
- Root Cause: Winter plug pops out of the return line due to improper sizing or pipe expansion.
- Actionable Fix: Replace the rubber expansion plug with a slightly larger size, clean out any scale or Teflon tape buildup inside the PVC fitting, and tighten the wing nut firmly until the rubber gasket fully compresses.
- Root Cause: Spring opening reveals heavy green water filled with algae blooms despite closing chemical treatment.
- Actionable Fix: The winterizing algaecide degraded prematurely due to high sunlight penetration or low initial concentration. Double-shock the pool with unstabilized granular chlorine and run the filter 24/7 until clarity returns.
Frequently Asked Questions
Do I need to remove my above ground pool liner for the winter?
No, never remove your vinyl liner during winter. Keeping the liner in place and maintaining the water level keeps the wall structure stable against ground pressure and freezing weather. Removing the liner ruins its elasticity and makes reinstallation nearly impossible.
When is the exact right time to close my above ground pool?
Close your pool when the local water temperature drops consistently below 65°F (18°C) for several consecutive days. Closing too early while water is warm triggers algae growth because chlorine degrades rapidly. Closing too late risks frozen pipes and cracked equipment.
Can I use regular pool antifreeze in my above ground pool lines?
You must use non-toxic, propylene glycol-based pool antifreeze specifically rated for plumbing winterization. Never use automotive ethylene glycol antifreeze, as it is highly toxic to humans, pets, and wildlife, and can degrade PVC pool plumbing components.
How do I stop the wind from blowing my winter cover off?
Ensure your cable and winch are tightened down securely around the perimeter posts rather than relying on the cover's elastic band alone. For extreme wind zones, wrap heavy-duty ratchet straps completely around the outside circumference of the pool wall over the cover.
Mastering your pool's winter shutdown protects your hardware and guarantees crystal-clear water when swimming season returns. Stock up on your winterizing chemicals and inspect your equipment today to close your pool like a professional.
