How To Close An Above Ground Pool: The Complete Winterization Guide
Closing an above ground pool properly requires lowering the water level below the skimmer, balancing chemical parameters to prevent algae blooms, and installing a heavy-duty winter cover to protect pool walls and liners from freeze-thaw damage. Completing these steps before temperatures drop below freezing ensures your pool structure remains intact and simplifies spring pool opening.
Pre-Operation & Equipment Checklist
Winterizing an above ground pool requires deliberate preparation to protect your investment against harsh freeze-thaw cycles, ice expansion, and corrosive chemical reactions. Failing to winterize correctly often leads to ripped vinyl liners, cracked return fittings, and severe structural corrosion.
- Essential Gear and Tools: Winterizing chemical kit (shock, algaecide, and closing float or slow-dissolving tabs), pool cover pump or siphon, heavy-duty winter cover, winch and cable assembly, cover air pillow or ice compensator, skimmer faceplate cover or winterizing plate, pipe plugs or expansion plugs, garden hose, and water testing kit.
- Prerequisite Standards: Water chemistry must be balanced before adding closing chemicals. Total alkalinity should read between 80 to 120 ppm, pH must sit between 7.2 and 7.8, and calcium hardness should fall between 200 and 400 ppm.
- Budget and Duration Benchmarks: The entire process requires approximately $50 to $150 in supplies depending on pool volume and chemical kits, and takes roughly 3 to 5 hours of active labor across a single afternoon.
Step-by-Step Above Ground Pool Winterization Workflow
Step 1: Deep Clean and Balance Water Chemistry
Begin by thoroughly vacuuming the pool floor, brushing the pool walls to dislodge embedded algae spores, and skimming out all floating debris. Bring your water sample to a local pool store or test it using a reliable digital or drop-based kit, adjusting the total alkalinity, pH, and calcium hardness to their ideal ranges.
Warning: Never add chlorine shock and copper-based algaecide simultaneously, as mixing concentrated chemicals can cause chemical reactions that stain pool liners or degrade metal components. Allow chlorine levels to drop below 5 ppm before pouring in algaecide.
Step 2: Lower the Water Level and Purge Plumbing Lines
Drain the water level using a submersible pump, a siphon, or your pool pump (if equipped with a waste setting) to a safe point roughly 4 to 6 inches below the skimmer intake and return jet. If you reside in a region with severe, prolonged freezing winters, you must lower the water level 12 to 18 inches below the skimmer, or completely drain the lines to prevent frozen water from cracking the PVC pipes and skimmer housing.
Pro-Tip: Disconnect all flexible hoses leading to and from the pump, filter, and chlorinator, then drain them completely and store them inside a dry garage or shed to prevent cracking from trapped residual water.
Step 3: Blow Out Lines and Install Winter Plugs
If you have a permanent hard-plumbed filtration system, use a shop vac in blow mode or an air compressor to force any remaining water out of the underground or above-ground return lines. Once air bubbles continuously surface, insert a rubber expansion plug equipped with a stainless steel bolt into the return fitting from inside the pool, tightening it securely.
Step 4: Protect the Skimmer and Install the Air Pillow
Install a specialized skimmer winter plate or a skimmer cover over the skimmer mouth to prevent rain and melting snow from filling the housing and freezing. Inflate a heavy-duty vinyl air pillow to approximately 60 to 70 percent capacity and tie it with nylon rope to the center of the pool; this pillow absorbs the crushing lateral pressure exerted by freezing ice sheets, protecting your above-ground pool walls.
Step 5: Secure the Winter Cover and Winch
Center your winter cover across the pool surface, allowing the excess material to drape evenly over the pool's top ledge. Thread the steel cable provided with the cover through the designated eyelets around the perimeter of the cover, feed the cable through the metal ratchet winch, and crank it tightly until the cover is firmly secured against the pool frame.
Easiest Way To Close Above Ground Pool at Helen Shields blog
Above Ground Pool Closing Method Comparison
| Feature/Method | Partial Drain Method (Mild Climates) | Complete Drain & Blowout (Severe Climates) | Air Pillow & Skimmer Plate Method |
|---|---|---|---|
| Water Level | 4 to 6 inches below skimmer | 12 to 18 inches below skimmer | Below skimmer level |
| Line Protection | Expansion plugs and valve closing | Complete air purge and disconnect | Expansion plugs with antifreeze |
| Ice Protection | Relies on natural surface give | Air pillow ice compensator required | Air pillow centered under cover |
| Ideal Region | USDA Zones 7 through 10 | USDA Zones 3 through 6 | All freezing climates |
Common Site Failures and Field Fixes
- Root Cause: The winter cover collapses into the pool center under heavy snow or rain loads.
- Actionable Fix: Inspect the air pillow to ensure it is properly centered and tied down securely with nylon rope. Pump off accumulated standing water from the top of the cover using a pool cover pump, and tighten the winch cable.
- Root Cause: Green, swampy water develops beneath the winter cover by early spring due to insufficient closing chemicals.
- Actionable Fix: Ensure you added a long-lasting winter algaecide in late autumn. If water clarity degrades, pull back a corner of the cover on a mild day and broadcast liquid chlorine shock directly into the water, then re-secure the cover.
- Root Cause: Skimmer housing cracks or breaks apart during sub-freezing temperatures.
- Actionable Fix: Water leaked into the skimmer housing because the winter skimmer plate was installed incorrectly or lacked a watertight seal. Replace the cracked skimmer housing in the spring and ensure the replacement plate is sealed with plumber's tape or silicone gaskets.
Frequently Asked Questions
Should I drain my above ground pool completely for the winter?
No, you should never completely drain an above-ground pool for the winter. The weight of the remaining water provides necessary structural counter-pressure against the pool walls to withstand heavy ground shifts, high winds, and freezing soil pressure. Emptying a vinyl-liner pool can also cause the liner to shrink, dry out, and crack.
When is the ideal time to close my above ground pool?
You should close your pool when consistent water temperatures drop below 65 degrees Fahrenheit, typically in mid-to-late autumn. Closing the pool at this temperature prevents algae growth, which thrives in warm water, while ensuring you finish the physical labor before freezing weather arrives.
Do I need to run my pool filter all winter?
No, running a pool filter through the winter is unnecessary and exposes your expensive pump and filter tank to potential freeze damage. Once the pool is properly winterized, chemically treated, and sealed with a cover, turn off the electrical breaker to the pump system for the entire season.
How do I keep water off the top of my winter cover?
Use an electric submersible pool cover pump or a manual siphon pump to remove standing rain and melted snow whenever it accumulates past a depth of two inches. Keeping excess weight off the cover prevents undue strain on the cable, winch, and top ledges of your pool frame.
Protect Your Pool Investment Today
Properly winterizing your above-ground pool safeguards your equipment, prevents costly structural liner replacements, and guarantees crystal-clear water when swim season returns. Take time this weekend to balance your water chemistry, drain your plumbing lines, and secure a heavy-duty winter cover for total peace of mind.
