8 Essential Supplies Needed to Winterize a Backyard Pool

Closing down a backyard pool for the season is more than just throwing a tarp over the water and hoping for the best. Failing to protect your investment against freezing temperatures can lead to cracked pipes, ruined liners, and a green swamp come spring. Investing in the right winterizing supplies now saves thousands of dollars in repairs and guarantees a stress-free opening day when warm weather returns.

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Why Winterizing Your Pool Correctly Matters

Water expands by about nine percent when it freezes, exerting immense pressure on anything containing it. In a backyard pool, this expansion can easily crack underground PVC pipes, split heavy-duty plastic skimmers, and warp filtration tanks. Correctly winterizing your pool acts as an insurance policy against these hidden, high-cost structural failures.

Beyond structural defense, winterization preserves water chemistry and protects the interior finish of the pool. Allowing organic debris to sit in untreated, stagnant water for six months creates deep stains on plaster and vinyl liners that are incredibly difficult to scrub out. A systematic close-down routine ensures you are not spending your entire spring budget on heavy chemical treatments and stain removers.

Safety Pool Cover – Loop-Loc Mesh Safety Cover

A safety pool cover is the primary shield that keeps debris, pets, and children out of the pool during the off-season. Standard tarp covers secured by water bags can easily slip, collapse under snow loads, or collect stagnant puddles that become breeding grounds for mosquitoes. A true safety cover anchors directly into the deck, creating a taut, impenetrable barrier that handles heavy winter weather with ease.

The Loop-Loc Mesh Safety Cover is a premier choice for off-season protection due to its legendary burst strength and precise fit. Made from dense polyester mesh, it allows rain and melting snow to drain through while blocking leaves, twigs, and fine debris. This eliminates the dangerous puddle buildup on top of the cover, while the high-tensile brass anchors and stainless steel springs keep the fabric drum-tight even under heavy snow loads.

Before purchasing, accurate pool measurements are vital because safety covers require a specific overlap and must match the pool’s exact shape. Installation requires drilling anchor holes into concrete, wood, or pavers, which may require renting a rotary hammer drill if you are going the DIY route.

• Material: Super Dense Mesh (blocks 95% of sunlight to prevent algae growth)
• Break Strength: Exceeds ASTM safety standards (up to 4,000 lbs)
• Deck Compatibility: Concrete, wood, or brick pavers (with specific anchors)
• Warranty: 15-year pro-rated manufacturer warranty

This cover is ideal for pool owners who prioritize safety, have kids or pets, and live in areas with heavy snowfall. It is not the right choice for budget-focused owners looking for a quick, temporary fix, or those with highly irregular, custom rock waterfalls that cannot accommodate anchor points.

Winter Chemical Kit – In The Swim Deluxe Kit

Balancing your water chemistry before closing is only half the battle; those chemicals naturally dissipate over the long winter months. A dedicated winter chemical kit uses slow-release sanitizers and specialized enzymes to keep the water clear and prevent algae from taking hold as temperatures fluctuate. Without these long-acting agents, spring opening becomes a nightmare of green water and clogged filters.

The In The Swim Deluxe Kit contains a perfectly pre-measured combination of powerful winterizing agents designed to treat pools up to 35,000 gallons. It features a non-chlorine winter shock to oxidize contaminants, a powerful winterizer algaecide, and a slow-releasing chemical floater packed with non-chlorine sanitizer. The inclusion of a specialized stain rust and scale preventer ensures that mineral deposits do not bond to the pool walls while the filtration system is dormant.

Users need to ensure the pool water is fully balanced (pH, alkalinity, calcium hardness) before adding the kit contents. The slow-release dispenser must be weighted and placed in the center of the pool, and it is crucial to run the pump for at least four to six hours after adding the chemicals to distribute them evenly before lowering the water level.

• Treats Pool Sizes: Available for pools up to 10k, 20k, or 35k gallons
• Kit Contents: Winter Shock, Winter Algaecide, Slow-Release Floater, Stain & Scale Metal Free
• Safe For: Vinyl, fiberglass, and plaster/gunite pools

This kit is perfect for pool owners who want a straightforward, pre-packaged chemical regimen without the guesswork of buying separate products. It is not ideal for those who prefer alternative sanitation systems that require specialized, brand-specific chemicals.

Pool Air Pillow – Robelle Ice Equalizer Pillow

When ice forms on a closed pool, it expands outward, exerting tremendous pressure against the pool walls and potentially warping or splitting the structure. An air pillow sits in the center of the pool under the winter cover, acting as a sacrificial pressure absorber. By compressing when ice forms, the pillow relieves lateral pressure and forces the ice to expand upward and inward rather than outward.

The Robelle Ice Equalizer Pillow stands out because it is built from heavy-duty, 16-gauge vinyl that resists punctures and leaks during extreme temperature drops. Unlike cheap, thin pillows that deflate mid-winter, this model features reinforced grommets on all four corners to make centering and securing the pillow straightforward. Its rugged valve design prevents slow air leaks, ensuring it stays fully inflated through the harshest winter freeze-thaw cycles.

The most common mistake is inflating the air pillow to 100% capacity; it should only be inflated to about 60% to 70% fullness. This leaves room for the pillow to compress under ice pressure without popping. Additionally, always use nylon ropes tied to the corner grommets to keep the pillow perfectly centered in the pool.

• Dimensions: Available in 4′ x 4′, 4′ x 8′, and 4′ x 15′ sizes
• Material: 16-Gauge heavy-duty PVC vinyl
• Securing Method: Four-corner reinforced grommets

This is an absolute necessity for above-ground pool owners and in-ground pool owners using solid winter covers in freezing climates. It is unnecessary for pool owners in warm regions that never experience freezing temperatures or those using taut, mesh safety covers that do not collect standing water.

Expansion Plug – Poolzilla Winterizing Plug

Once you blow the water out of your plumbing lines, you must seal those pipes to prevent water from seeping back in and freezing. Expansion plugs expand inside the return lines and cleaner ports, creating an airtight, watertight seal deep inside the pipe opening. Without these plugs, water will inevitably find its way back into the lines, leading to underground pipe ruptures that are incredibly disruptive and expensive to repair.

The Poolzilla Winterizing Plug is engineered with heavy-duty premium rubber and stainless steel hardware to resist chemical degradation and rust. The ergonomic nylon wing nut makes it easy to tighten the plug securely by hand without stripping the threads or requiring specialized tools. Its tapered design ensures a snug, custom fit inside the pipe, while the high-grade rubber body adapts to minor imperfections inside the fittings to form an absolute seal.

Pool plumbing lines come in various diameters, so measuring the internal diameter of your return lines—usually 1.5 inches or 2 inches—is critical before ordering. When installing, wipe the inside of the pipe fitting clean of any algae or debris to ensure the rubber makes direct, slip-free contact with the PVC wall.

• Sizes Available: #8 (1.25″), #9 (1.5″), #10 (1.625″), #11 (1.75″), #12 (2″)
• Materials: Industrial rubber body, 304 stainless steel bolt, nylon wing nut
• Application: Return lines, skimmers, cleaner lines, and filtration ports

These plugs are essential for any pool owner in a freezing climate who needs to secure threaded or smooth PVC plumbing lines. They are not suitable for threaded returns that require specific threaded male-end plugs, though they work perfectly as universal backup plugs for smooth openings.

Pool Antifreeze – Splash Pool & Spa Antifreeze

Even after blowing out plumbing lines, some residual water can remain in low spots, elbows, or hard-to-reach underground runs. Pool antifreeze acts as a critical fail-safe by mixing with this remaining moisture to lower its freezing point well below zero. This prevents the remaining water from crystallizing, expanding, and splitting the subterranean PVC pipes during deep winter freezes.

Splash Pool & Spa Antifreeze is formulated specifically for recreational water systems, utilizing a non-toxic propylene glycol base that is safe for pool surfaces and plumbing. It protects plumbing lines down to -50 degrees Fahrenheit, providing a massive safety margin during extreme cold snaps. Unlike automotive antifreeze, which is highly toxic and will damage vinyl liners and pool equipment, this formula is completely biodegradable and easily rinses away during spring start-up.

This product must never be added to the pool’s main body of water or run through the pool filter or heater. It is designed solely to be poured directly into the skimmer lines and return pipes after they have been blown out and plugged at the pool end. Ensure you purchase non-toxic propylene glycol pool antifreeze, as ethylene-glycol-based automotive alternatives will ruin your pool and pose severe environmental hazards.

• Base Ingredient: Propylene Glycol (non-toxic, eco-friendly formula)
• Temperature Rating: Burst protection down to -50°F (-46°C)
• Volume: 1-gallon bottles (usually sold in multi-packs)

This is highly recommended for pool owners in Northern climates where ground freeze depths reach several feet. It is not necessary for pool owners in mild climates where winter temperatures rarely drop below freezing for more than a few hours.

Skimmer Guard – Ultra Gizzmo Skimmer Protector

The skimmer is one of the most vulnerable parts of a pool because it sits right at the water line where ice forms first. When water inside the skimmer well freezes, it expands outward, easily cracking the plastic housing and causing a major underground leak that requires breaking up the concrete deck to repair. A skimmer guard acts as a sacrificial expansion tube, absorbing the crushing pressure of the ice so the skimmer wall does not have to.

The Ultra Gizzmo Skimmer Protector is the industry standard because it combines a heavy-duty, blow-molded plastic expansion tube with built-in male threads. It screws directly into the bottom of the skimmer line, sealing off the plumbing pipe while simultaneously filling the skimmer throat with its compressible chamber. The integrated freeze-expansion core is designed to deform under pressure, protecting the delicate skimmer throat from ice damage without cracking or failing.

Gizzmos come in different lengths and thread sizes, with the Ultra model featuring 1.5-inch and 2-inch double-threaded ends to fit most standard skimmers. Always use Teflon tape on the threads of the Gizzmo before screwing it in to ensure a watertight seal that prevents water from seeping down into the winterized plumbing line.

• Thread Size: Dual 1.5″ and 2″ tapered male threads
• Length: 16 inches (ideal for deep-throated skimmers)
• Material: High-density, compressible polyethylene

This is an absolute must-have for in-ground pool owners in freezing climates who want to protect their skimmer wells without lowering the pool water level below the skimmer mouth. It is not suitable for above-ground pool skimmers that are disconnected and drained entirely for the winter.

Pool Cover Pump – Little Giant APCP-1700 Pump

Solid winter covers and safety covers with debris barriers naturally accumulate rain and melting snow over the winter. This standing water creates a massive weight load that can pull the cover into the pool, stress the anchor points, and create a safety hazard for children and wildlife. A dedicated pool cover pump automatically removes this water, preserving the structural integrity of your cover and keeping the top surface dry.

The Little Giant APCP-1700 Pump is an exceptional automatic submersible pump designed specifically for the rigors of winter pool maintenance. It features an integrated mechanical float switch that automatically turns the pump on when water reaches two inches and shuts it off when the surface is clear, eliminating the need for manual monitoring. With a pumping capacity of 1,700 gallons per hour, it rapidly clears heavy rain accumulations before they can stress your cover anchors.

The pump comes with a standard garden hose adapter, but using a high-quality, kink-free discharge hose is essential to prevent blockages that can burn out the motor. Keep the intake screen clean of wet leaves and organic debris, as a clogged intake will cause the pump to run dry and overheat despite its built-in thermal overload protection.

• Flow Rate: 1,700 Gallons Per Hour (GPH)
• Activation: Automatic (on at 2″, off at 1″)
• Power Cord Length: 25-foot heavy-duty power cord
• Discharge Connection: 3/4″ garden hose adapter

This pump is ideal for owners of solid pool covers or hybrid covers that accumulate heavy standing water during the fall and winter. It is unnecessary for owners of open mesh safety covers, as rain and snow drain directly through the mesh fabric into the pool water below.

Pool Leaf Net – Blue Wave In-Ground Leaf Cover

If you live in an area surrounded by deciduous trees, autumn can dump hundreds of pounds of wet, decaying leaves onto your pool cover. Trying to scoop these soggy leaves off a heavy winter cover in the spring is exhausting, messy work that often ends with dirty water dumping back into the clean pool. A leaf net sits on top of your main winter cover, acting as a lightweight catcher’s mitt that can be easily peeled off once the autumn leaf drop is complete.

The Blue Wave In-Ground Leaf Cover is woven from durable, UV-protected polyethylene mesh that easily handles the weight of wet foliage without tearing. It features a generous four-foot overlap that ensures complete coverage of the pool edges, preventing wind from blowing leaves underneath. Once all the leaves have fallen, you simply undo the securing weights or straps, lift the lightweight net off, and dump the collected leaves in one easy motion, leaving your main cover pristine.

This net is designed to be removed before the first major snow or hard freeze; leaving it on all winter can cause it to freeze to the main cover, rendering it impossible to remove without damage. When sizing, always order a net that matches your pool size plus the overlap, ensuring you have enough material to sag slightly and lay flat against the main winter cover.

• Material: Woven polyethylene mesh with UV-inhibitors
• Overlap: 4 feet (exceeds the industry standard of 3 feet)
• Sizes: Available in standard in-ground rectangular and round configurations

This is ideal for pool owners with heavy tree coverage who experience a massive autumn leaf drop. It is not necessary for pool owners in desert or coastal regions with minimal deciduous foliage, or those who close their pools after all leaves have already fallen.

How to Blow Out Pool Lines Like a Professional

Blowing out your plumbing lines is the most critical step in preventing freeze damage, requiring a systematic approach to ensure no water is trapped. Start by lowering the pool water level below the skimmers (unless using a Gizzmo) and hooking a high-volume air blower or a heavy-duty shop vac to your filtration system. Always blow the lines out from the pool equipment pad back toward the pool to ensure the air pushes the water downhill naturally.

Work on one line at a time by closing the valves to all other lines, focusing the full force of the air pressure onto a single run. Once you see a geyser of water shoot out of the return fitting and turn into a steady mist of air, quickly slide your expansion plug into the fitting and tighten it securely. Repeat this process for each return line, the main drain (where you look for a massive air bubble column before closing the valve at the pad), and finally the skimmer lines.

Storing Your Pool Pump and Filter for Winter

Leaving water inside your pump housing, filter tank, or heater over the winter will cause catastrophic cracking as the water freezes and expands. Start by removing the drain plugs from the bottom of your pump strainer pot, filter tank, and heater header. Store these small drain plugs inside the pump basket so they do not go missing during the winter months.

If you have a multi-port valve, set the handle to the “Winterize” or “Closed” position to relieve pressure on the internal spider gasket and allow air to circulate. For cartridge or D.E. filters, remove the elements entirely, hose them down to remove organic debris, and store them in a dry, rodent-free area like a garage or basement. If possible, disconnect the pump motor entirely and store it indoors to protect the delicate electrical windings from moisture and freezing temperatures.

Spring Opening Mistakes You Can Avoid Right Now

A successful spring opening starts with the choices you make during autumn winterization. The most common mistake is closing the pool too early when the water temperature is still above 60 degrees Fahrenheit. Algae thrives in warm water, so closing your pool before the ambient temperatures drop consistently below 60 degrees invites early algae blooms beneath the cover.

Another critical mistake is ignoring water chemistry during the winterizing process. Simply tossing in chemicals without balancing the pH and calcium hardness beforehand renders the winterizing kit far less effective and can lead to scale buildup on the pool walls. Taking an extra 20 minutes to balance the water, run the filter, and install high-quality plugs ensures that you will peel back the cover in spring to reveal crystal-clear, ready-to-swim water.

Conclusion

Taking the time to winterize your pool with the right supplies is the ultimate way to protect your backyard investment. By choosing reliable covers, durable plugs, and specialized winter chemicals, you safeguard your plumbing and equipment from expensive freeze damage. When the warm weather rolls around, you will be rewarded with a quick, painless pool opening and more time to enjoy the water.