How To Close A Pool For Winter Above Ground
Proper above ground pool winterization prevents freeze-thaw structural damage, liner cracking, and severe algae blooms during the off-season. Achieving a successful winterizing process requires dropping the water level below the skimmer, balancing chemical parameters to industry standards, and securing a heavy-duty winter cover.
Pre-Operation & Equipment Checklist
Executing a professional-grade pool closing requires gathering precise chemical treatments and maintenance hardware before beginning the physical labor. Failing to prepare these elements can result in freezing pipes, torn vinyl liners, and green water upon spring reopening.
- Essential gear, tools, and materials: Test kit or strips, winter algaecide, non-chlorine shock, pool antifreeze (propylene glycol), a winter cover, a cover winch and cable, air compressor or shop vac, plugs for return jets, and skimmer closure plates.
- Mandatory prerequisite knowledge and standards: Water must be balanced to a pH of 7.2 to 7.6, total alkalinity between 80 to 120 ppm, and calcium hardness between 180 to 220 ppm. Ambient temperatures should consistently remain below 65 degrees Fahrenheit.
- Estimated budget and duration benchmarks: Financial investment typically ranges from one hundred to three hundred dollars depending on chemical stocks and cover quality, with a total execution time of three to five hours.
Step-by-Step Above Ground Winterization Workflow
Step 1: Deep Clean and Clear Debris
Remove all ladders, solar blankets, skimmer baskets, and wall-mounted pool accessories from the water to prevent rust, staining, and plastic degradation over the winter. Skim the surface thoroughly, brush down the walls to dislodge microscopic debris, and vacuum the entire floor to eliminate organic matter that consumes sanitizers.
Pro-Tip: Leaving organic debris in the pool during winter guarantees a severe algae bloom that will require massive quantities of chlorine and clarifier to clear in the spring.
Step 2: Balance Water Chemistry
Adjust the chemical profile of the water to protect the pool liner and equipment from scale buildup, corrosion, and biological growth. Test and correct the pH, total alkalinity, and calcium hardness using granular balancing agents dissolved in a bucket of warm water before broadcasting.
Warning: Never add chlorine and algaecide simultaneously, as they can neutralize each other; wait at least twenty-four hours between adding a shock treatment and winter algaecide.
Step 3: Lower the Water Level
Drain the water level to a safe threshold relative to your specific skimmer design and geographic freezing depth. For standard above ground pools, lower the water level approximately four to six inches below the return jet if you are removing the skimmer, or below the skimmer faceplate if using a skimmer gizmo and winter closure plate.
Step 4: Blow Out and Plug the Plumbing Lines
Disconnect the hoses running between the pool, pump, and filter system, draining all residual water completely to prevent cracked housings from ice expansion. Use a shop vacuum or air compressor to blow air through the return line from the pool side until bubbles cease, then immediately insert an expansion rubber plug into the return jet.
Step 5: Add Winterizing Chemicals and Protect Skimmer
Broadcast a concentrated winter algaecide and a non-chlorine shock treatment across the surface of the pool to maintain chemical sanitation through the cold months. If keeping the skimmer attached, install a skimmer guard or fill a skimmer gizmo with expansion foam to absorb ice pressure, and screw a faceplate cover securely over the opening.
Step 6: Install the Winter Cover and Cable
Center the heavy-duty winter cover over the pool surface, ensuring the excess material drapes evenly over the outer ledge of the frame. Thread the stainless steel cable through the eyelets of the cover, connect it to the winch, and crank it tightly to secure the cover against high winds and storms.
How To Winterize An Above Ground Swimming Pool | Storables
Above Ground Winterization Chemical Matrix
| Chemical Parameter | Optimal Winter Range | Purpose and Function | Failure Consequence |
|---|---|---|---|
| pH Level | 7.2 - 7.6 | Maintains balanced water to prevent skin irritation and equipment corrosion. | High pH causes scale; low pH wrinkles vinyl liners. |
| Total Alkalinity | 80 - 120 ppm | Acts as a buffer to stabilize pH fluctuations. | Causes erratic pH levels and metal staining. |
| Calcium Hardness | 180 - 220 ppm | Prevents water from leaching minerals out of vinyl liners. | Causes liner pitting, brittleness, and shrinkage. |
| Winter Algaecide | Follow label instructions | Suppresses algae spore germination during freezing months. | Results in swampy, algae-filled water in spring. |
Common Site Failures and Field Fixes
- Root Cause: The winter cover collapses into the pool center under rain and snow weight.
- Actionable Fix: Pump standing water off the cover immediately using a cover pump, and install a winter pillow or air cushion beneath the center of the cover to displace weight toward the edges.
- Root Cause: Water freezes inside the return plumbing lines, cracking the PVC fittings or above ground hoses.
- Actionable Fix: Completely drain all hoses, store them indoors, blow compressed air through the return lines, and apply pool antifreeze before inserting tight rubber expansion plugs.
- Root Cause: Green, swampy water develops beneath the cover by mid-winter.
- Actionable Fix: Ensure the winter algaecide dosage was adequate for your pool volume, and verify that the cover is completely opaque to block sunlight, which fuels algae photosynthesis.
Frequently Asked Questions
Do I need to drain my above ground pool completely for winter?
No, draining an above ground pool completely for winter is extremely dangerous because the hydrostatic pressure from surrounding frozen ground can collapse the metal walls and ruin the vinyl liner. Always keep the pool filled with water, lowering it only a few inches below the filtration openings.
Can I leave my pool pump and filter outside during winter?
Leaving the pump, filter, and motor outside is acceptable only if they are entirely disconnected, drained of all water, and stored upside down or in a protected, dry location like a shed or garage. Residual water trapped inside plastic pump housings will freeze and crack the internal volute.
When is the exact right time to close an above ground pool?
The ideal time to close an above ground pool is in late autumn when water temperatures consistently drop below 65 degrees Fahrenheit for several consecutive days. Closing the pool too early while water is warm encourages rapid algae growth, while closing it too late risks unexpected early freezes.
How do I keep my winter cover from blowing away in high winds?
Secure the winter cover by tightening the steel cable and winch system completely around the perimeter of the top rail. Additionally, wrap heavy-duty cover clips or wall wraps around the edge of the frame to prevent wind from catching underneath the material.
Protect your pool investment this season by sourcing professional-grade winterization chemicals and heavy-duty covers engineered to withstand harsh winter conditions. Proper closing techniques ensure a crystal-clear swim environment when warm weather returns.
