How To Close An Above Ground Pool For Winter: The Complete Step-by-Step Technical Guide
Closing an above ground pool properly involves balancing water chemistry, lowering the water level safely below the skimmer, and installing a heavy-duty winter cover to protect structural components from freeze-thaw damage. Completing this multi-step winterization process before temperatures consistently drop below freezing prevents costly liner tears, equipment cracking, and severe algae blooms by spring.
Pre-Winterization Equipment, Chemical, and Tool Checklist
Executing a professional-grade winterization requires careful planning to ensure every component of the pool structure and circulation system is fully protected against sub-zero temperatures. Gathering all necessary materials beforehand prevents mid-process interruptions and ensures your pool survives freezing conditions intact.
- Essential Equipment and Tools: Submersible electric water pump, garden hose, heavy-duty winter pool cover, winch and cable tightening kit, winter cover air pillow, skimmer closing plate or gizmo, pliers, channel locks, and a soft-bristle pool brush.
- Water Treatment Chemicals: pH increaser or decreaser, total alkalinity balancers, calcium hardness increaser, heavy-duty winterizing algaecide, slow-dissolving winter floater or non-chlorine shock, and stain preventer.
- Prerequisites and Environmental Standards: Ambient air temperatures must remain consistently below 65 degrees Fahrenheit for at least five consecutive days to prevent premature algae growth after closing. Complete a thorough vacuuming and wall brushing 48 hours prior to chemical balancing to ensure suspended debris settles and can be completely removed.
- Budget and Time Benchmarks: Expect to spend between fifty to one hundred and fifty dollars on specialized winter chemicals and hardware if replacing worn gizmos or covers. Allocate approximately three to five hours of active labor spread across a 48-hour chemical stabilization window.
Step-by-Step Above Ground Pool Winterization Workflow
Step 1: Deep Cleaning and Debris Removal
Begin the closing process by thoroughly vacuuming the pool floor to remove all organic matter, leaves, and silt that could stain the vinyl liner or fuel organic growth over the winter. Brush the walls and tile line using a stiff-bristled nylon brush to dislodge clinging algae spores and biofilm. Skim the surface to capture floating debris, and run the filtration system continuously for 24 hours to filter out fine particles before proceeding.
Warning: Never drain an above ground pool completely for winter. The hydrostatic pressure of the surrounding saturated soil, combined with the structural tension of the water against the vinyl liner, keeps the wall upright. An empty or severely over-drained pool will experience catastrophic wall collapse or liner shrinkage.
Step 2: Water Chemistry Balancing and Stabilization
Test the pool water using a reliable DPD test kit or digital photometer and adjust the chemical parameters to ideal winterization ranges. Set the pH between 7.2 and 7.6, total alkalinity between 80 and 120 parts per million, and calcium hardness between 180 and 220 parts per million to prevent metal corrosion and scale scaling. Once balanced, add a concentrated winter algaecide and a maintenance dose of non-chlorine shock, allowing the pump to circulate the mixture for at least eight hours.
Step 3: Lowering the Water Level and Purging Plumbing Lines
Lower the water level using a submersible electric pump to a point approximately four to six inches below the return jet and skimmer mouth, or follow the specific manufacturer guidelines for your skimmer style. Disconnect the flexible hoses running between the pool wall, the pump, and the sand or cartridge filter. Completely drain the pump housing, filter tank, and chlorinator by removing their respective winter drain plugs to prevent trapped water from freezing, expanding, and cracking the heavy-duty plastic housings.
Step 4: Installing Skimmer Protection and Air Pillows
Insert a threaded winter gizmo or expansion plug into the bottom skimmer port to seal off the line against incoming water, or install a dedicated skimmer faceplate cover. Inflate a heavy-duty vinyl air pillow to roughly sixty percent capacity and place it securely in the exact center of the pool using tether lines attached to the top rails to absorb ice expansion pressure.
Pro-Tip: Placing the air pillow off-center or over-inflating it can cause the pillow to drift toward the edges or burst under pressure, leaving your winter cover unsupported and vulnerable to accumulating heavy snow loads.
Step 5: Securing the Winter Cover and Final Inspection
Center the heavy-duty winter cover over the pool surface, ensuring an even overhang around the entire perimeter of the top ledge. Thread the steel cable through the grommets of the cover and secure it tightly using the included winch mechanism, locking it down firmly against high winter winds. Pump any standing rainwater off the top of the cover periodically throughout the winter months to maintain structural integrity.
Easiest Way To Close Above Ground Pool at Helen Shields blog
Technical Comparison of Above Ground Pool Closing Methods
| Winterization Parameter | Standard Standard Method | Premium Maintenance Method | Minimalist Quick Method |
|---|---|---|---|
| Water Level | 4-6 inches below skimmer | 12-18 inches below skimmer | Just below return jet |
| Plumbing Protection | Hoses removed, plugs out, lines blown | Hoses removed, antifreeze added | Hoses disconnected, plugs out |
| Cover Type | Standard woven polyethylene | Heavy-duty solid mesh with security straps | Basic tarp with water tubes |
| Algae Defense | Winter algaecide + non-chlorine shock | Multi-stage enzyme and algaecide kit | Standard chlorine shock only |
Common Site Failures and Field Fixes
- Root Cause: The winter cover falls into the pool water during a heavy windstorm because the cable was not cinched tightly enough through the grommets.
- Actionable Fix: Release the winch tension, pull the excess cover material evenly around the perimeter, retread the cable through every alternating eyelet, and use a ratchet-style winch to secure the cable firmly beneath the top ledge.
- Root Cause: The pool pump housing cracks during the first hard freeze because residual water was left trapped inside the volute.
- Actionable Fix: Always remove all lower drain plugs immediately after shutting down the system, and store the pump and motor indoors or inside a dry shed for the winter season.
- Root Cause: Severe green algae blooms develop by early spring despite adding winter algaecide in the fall.
- Actionable Fix: Apply a secondary booster dose of concentrated winter algaecide in mid-winter if ambient temperatures rise above fifty degrees for an extended period, or ensure initial chemical levels were thoroughly circulated before closing.
Frequently Asked Questions
Should I drain my above ground pool completely for the winter?
No, you should never drain an above ground pool completely. The remaining water provides essential internal pressure that counteracts the weight of surrounding freezing soil and prevents the vinyl liner from shrinking, cracking, or pulling away from the top wall track.
How low should I drop the water level for closing?
The water level should typically be lowered to approximately four to six inches below the skimmer faceplate and return jet. If you use a skimmer closing plate, you may only need to drop the water a few inches below the skimmer mouth rather than draining below the return.
Do I need to remove my pool pump and filter for winter?
Yes, removing the pump, chlorinator, and cartridge filter elements and storing them indoors protects delicate plastic components from cracking due to trapped freezing water. Sand filters should be thoroughly drained, with the multiport valve set to the winterize position to allow internal air circulation.
When is the ideal time to close an above ground pool?
The best time to close your pool is in late autumn when water temperatures consistently drop below sixty-five degrees Fahrenheit. Closing too early while water is warm triggers rapid algae growth, while closing too late risks sudden freeze damage to your plumbing lines.
What is the purpose of the winter air pillow?
The air pillow floats in the center of the pool beneath the winter cover to absorb the lateral expansion pressure exerted by freezing ice sheets. By absorbing this stress, the pillow prevents the ice from pushing outward against the pool walls and protects the cover from ripping.
Get expert advice on maintaining your pool equipment year-round and explore our complete catalog of professional-grade winterization chemicals and supplies. Secure your pool today to guarantee a crystal-clear, hassle-free opening next season.
