10 Essential Pool Closing Winterization Supplies for a Backyard Pool

As the autumn leaves begin to fall and the air turns crisp, the time comes to transition your backyard pool from a summer oasis into winter hibernation. Neglecting this crucial seasonal transition can lead to thousands of dollars in cracked pipes, ruined liners, and a green swamp come spring. Equipping yourself with the right winterization gear now ensures your pool survives freezing temperatures and opens crystal clear next year.

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Why Proper Winterization Protects Your Backyard Pool

Water expands by about nine percent when it freezes. In a backyard pool, this expansion exerts immense pressure on PVC pipes, skimmer wells, and the pool shell itself. Without proper winter prep, expanding ice will easily crack plastic fittings and rupture underground plumbing lines, leading to devastating leaks that are incredibly expensive to locate and repair.

Beyond structural protection, closing a pool correctly prevents organic debris from taking over the water. Winterizing chemicals and physical barriers keep algae spores dormant and block sunlight, which is the primary fuel for algae growth. Skipping these steps means spending the first month of the next swim season fighting a stubborn, expensive chemistry battle instead of enjoying the water.

Finally, proper winterization protects your investment in pool equipment like pumps, filters, and heaters. Water left trapped inside these expensive components can crack casings and ruin internal seals overnight during a hard freeze. Taking the time to drain, blow out, and seal these systems preserves their operational lifespan for many summers to come.

Winter Chemical Kit – In The Swim Winterizing Kit

A pool closed with unbalanced, untreated water is a recipe for staining, scale buildup, and a massive algae bloom by spring. The In The Swim Winterizing Kit delivers a pre-measured, highly concentrated chemical punch designed to keep your water clear and balanced throughout the long dormant months. It eliminates the guesswork of buying separate chemicals by grouping everything you need into one convenient package.

• Available sizes: Configured for pools up to 10,000, 20,000, and 35,000 gallons
• Included components: Winterizing powder, copper-free winter algicide, metal sequestrant, and slow-release sanitizer floaters
• Compatibility: Safe for both vinyl-liner and plaster/concrete pools

What makes this specific kit the right choice is its combination of a powerful, non-chlorine oxidizer and a specialized slow-release floater. The oxidizer destroys organic contaminants without bleaching your pool liner, while the copper-free algicide prevents unsightly metallic staining on pool surfaces.

Before using this kit, ensure your pool water is completely balanced and clear, and run your filter for at least four hours after adding the chemicals to distribute them evenly. Secure the plastic chemical floater near the center of the pool so it does not drift and rest against a vinyl wall, which can cause localized discoloration.

This kit is perfect for pool owners wanting a straightforward, pre-packaged chemical routine, but it is not ideal for those with custom, ultra-large pools over 35,000 gallons who require specialized chemical dosing.

Pool Winter Cover – Blue Wave Bronze Winter Cover

Leaving a pool open to winter elements allows leaves, twigs, and dirt to accumulate, creating a thick layer of organic sludge. The Blue Wave Bronze Winter Cover acts as a heavy-duty shield, keeping debris out and blocking virtually all UV rays. Starving the water of sunlight prevents residual algae from photosynthesizing during milder winter days.

• Material: Rip-resistant woven polyethylene with a high scrim count
• Overlap: Generous 4-foot overlap to ensure secure anchoring on above-ground pools
• Durability: Heavy-duty, UV-stabilized material designed to resist cracking in extreme cold

This cover stands out because of its exceptional seam strength and heat-sealed construction, which prevents water from seeping through the fabric. The dark black underside is specifically engineered to block light penetration, which is your best defense against early spring algae blooms.

When purchasing, always select the cover size that matches your actual pool dimensions, as the manufacturer already factors in the extra overlap needed to drape over the top rails. Keep in mind that wind can easily damage a loose cover, so securing the perimeter tightly is critical for longevity.

This cover is an excellent, cost-effective choice for above-ground pool owners looking for durable seasonal protection, but it is not a safety cover and is not designed to support the weight of pets or children.

Pool Cover Pump – Little Giant APCP-1700 Pump

Rainwater and melting snow quickly accumulate on top of a pool cover, creating a heavy pool of standing water that strains your pool walls and cover anchors. The Little Giant APCP-1700 Pump is designed to automatically remove this accumulation before the weight causes structural damage or submerges your cover.

• Flow Rate: Moves up to 1,745 gallons per hour to quickly clear heavy water accumulation
• Activation: Automatic mechanical switch detects water at 2 inches and shuts off at 0.5 inches
• Power Cord: 25-foot heavy-duty power cord for easy reach to outdoor outlets

This pump is the premier choice because of its integrated freeze-protection design, which prevents the motor from burning out or freezing up in sub-zero temperatures. It features a wide, stable base that keeps it upright on the cover, and a built-in handle that makes placement and removal effortless.

To get the most out of this pump, place a small plastic pad or a smooth stepping stone under it on the cover to prevent the intake from sucking up the cover fabric itself. Always clear leaves and large debris from around the pump intake regularly to prevent clogging.

This pump is a must-have for pool owners in regions with heavy winter rain and snow, whereas it is unnecessary for those in dry, arid climates where cover water accumulation is rare.

Pool Air Pillow – Robelle Ice Equalizer Pillow

When water on top of and inside an above-ground pool freezes, it expands outward, putting immense pressure on the pool walls and top rails. The Robelle Ice Equalizer Pillow acts as a sacrificial cushion, absorbing this expansion pressure to protect your pool’s structural integrity.

• Material: Heavy-duty, 16-gauge vinyl designed to withstand extreme cold
• Size options: Available in 4′ x 4′, 4′ x 8′, and 4′ x 15′ sizes
• Valve: Leak-resistant speed valve for easy inflation and deflation

This air pillow is the right choice because of its puncture-resistant vinyl construction and reinforced grommet corners, which make it easy to secure in the center of the pool. As ice forms and expands inward, it compresses this air-filled pillow rather than pushing outward against your fragile pool walls.

The most critical mistake pool owners make is inflating the pillow to 100 percent capacity; instead, inflate the pillow to only 60 to 70 percent full. This leaves plenty of room for compression without popping the vinyl seams under the weight of the ice.

This is an essential safety net for above-ground pool owners in freezing climates, while pool owners in completely frost-free regions can safely bypass it.

Winter Expansion Plug – Anderson Grip-Tite Plug

Even after blowing out your pool plumbing, water can seep back into the return lines from the pool, leading to frozen and cracked pipes underground. The Anderson Grip-Tite Plug creates a completely airtight, watertight seal inside your return and cleaner lines to prevent water re-entry.

• Material: Non-corrosive nylon wing nut and bolt with industrial-grade rubber body
• Available sizes: Standard sizes to fit 1.5-inch and 2-inch plumbing lines
• Design: Wing-nut expansion style that requires no tools for installation

This plug is the industry standard because its heavy-duty nylon components will not rust, corrode, or strip out over time like cheaper metal-bolt plugs. The premium rubber compound remains flexible in extreme cold, ensuring a tight seal even when the temperature drops well below freezing.

Before inserting the plug, use a clean cloth to wipe any algae, slime, or grit from the inside of the pipe fitting to guarantee a clean seal. Tighten the wing nut until the rubber bulges firmly against the pipe walls, but do not use pliers, as hand-tightening is more than sufficient.

This plug is ideal for any pool owner looking for a reliable, reusable winter seal, but it is not meant to replace permanent threaded winter plugs on your actual pump and filter housings.

Skimmer Guard – Gizzmo Ultra Freeze Protector

Water entering the skimmer throat can easily freeze, expand, and crack the delicate plastic skimmer housing, leading to a major leak that requires tearing up concrete to fix. The Gizzmo Ultra Freeze Protector solves this by screwing directly into the skimmer drain line, sealing the pipe while acting as an expansion absorber.

• Length: 16 inches for deep-throat skimmers
• Threads: Dual 1.5-inch and 2-inch male threads to fit most skimmer models
• Material: Heavy-duty, blow-molded plastic designed to collapse under pressure

The Gizzmo is the right choice because its hollow, sealed tube is engineered to collapse inward when water freezes inside the skimmer well. This action absorbs the expansion force, saving your expensive skimmer plastic from cracking under pressure.

Always wrap the Gizzmo’s plastic threads with several layers of Teflon tape before screwing it in to ensure a watertight seal and to prevent the threads from binding over the winter. If your skimmer has non-standard threads, you will need a separate thread adapter for a proper fit.

This is a critical investment for in-ground pool owners in cold-weather regions, though it is not needed if you completely drain your pool water level below the skimmer mouth and keep it dry.

Pool Antifreeze – Splash RV & Marine Antifreeze

Even with a thorough line blowout, small pockets of water can pool in low spots of your underground pipes. The Splash RV & Marine Antifreeze provides vital secondary protection, ensuring that any residual moisture in your plumbing cannot freeze and rupture the pipes.

• Base: Non-toxic, propylene glycol formula (completely free of toxic ethylene glycol)
• Protection level: Burst protection down to -50°F (-46°C)
• Compatibility: Safe for copper, PVC, and plastic pool plumbing lines

This antifreeze is the right choice because of its non-toxic, eco-friendly formula, meaning it won’t harm your lawn, pets, or swimmers when the pool is reopened and backwashed in the spring. It is formulated to protect plumbing from bursting even in the deepest winter freezes.

Never use automotive antifreeze in your pool plumbing, as it is highly toxic and extremely difficult to safely remove from the pool environment. Always blow out the plumbing lines before pouring the antifreeze in to prevent diluting the solution, which reduces its cold-weather effectiveness.

This product is crucial for pool owners in deep-freeze states where underground lines run above the frost line, but it is unnecessary for mild winter climates where ground freezing does not occur.

Cover Cable and Winch – Swimline Cable Kit

High winter winds can easily get underneath an above-ground pool cover, ballooning it up and tearing it away from the pool frame. The Swimline Cable Kit provides the heavy-duty tension needed to lock the cover perimeter down flush against the pool walls.

• Cable composition: Multi-strand steel core with a weather-resistant, smooth vinyl coating
• Winch material: Heavy-duty, rust-proof cast aluminum
• Lengths available: Sized to fit pools up to 30 feet round or oval

This kit is the right pick because the vinyl coating on the steel cable prevents rust and protects your pool’s metal top rails from scratches and wear. The cast aluminum winch features a smooth ratcheting mechanism that allows you to crank the cable incredibly tight without slipping.

Avoid over-tightening the winch to the point of bending the pool’s metal top rails or ripping the cover grommets. Check the cable tension periodically throughout the winter, as heavy snow loads and high winds can cause the cable to stretch slightly over time.

This is a mandatory securement tool for above-ground pool owners using traditional winter covers, but it serves no purpose for in-ground pools using anchor-and-strap safety covers.

Pool Water Tester – Taylor Service Complete Kit

Closing your pool with incorrect water balance can lead to etching of plaster walls, scaling on pool surfaces, and rapid liner degradation over the winter. The Taylor Service Complete Kit (K-2006) uses precise liquid drop tests to give you professional-grade accuracy before you add your winter chemicals.

• Test types: Free/Combined Chlorine (FAS-DPD), pH, Acid/Base Demand, Total Alkalinity, Calcium Hardness, and Cyanuric Acid
• Reagent size: Large 2-ounce bottles for frequent testing
• Case: Heavy-duty, waterproof carrying case with integrated color-matching guides

This testing kit is the ultimate choice because it utilizes liquid reagents rather than unreliable paper test strips, which can degrade quickly and provide highly inaccurate readings. Accurate chemistry testing ensures you add the exact amount of winterizing chemicals required, preventing chemical waste and liner damage.

Always store this testing kit in a climate-controlled environment indoors, as freezing winter temperatures or extreme heat will ruin the liquid reagents and render them useless. Rinse the testing vials thoroughly with fresh tap water after each test to prevent chemical residue buildup.

This kit is perfect for dedicated pool owners who want precise control over their water chemistry, but it may be overkill for those who prefer taking water samples to a local pool store for analysis.

Skimmer Cover – Aquador Skimmer Faceplate Lid

Draining your pool water below the skimmer mouth to winterize it wastes water and can cause vinyl liners to shrink or pull away from the pool walls. The Aquador Skimmer Faceplate Lid solves this by creating a completely watertight snap-on barrier over the skimmer mouth, allowing you to keep your pool water at normal operating levels.

• Material: UV-resistant and chemical-resistant plastic
• Closure type: Snap-on, tool-free lid
• Compatibility: Models available for standard and wide-mouth skimmers

This product is highly recommended because it eliminates the need to drain several inches of water every autumn and refill it every spring. Keeping the water level high also helps brace the pool walls against winter wind and ice pressure.

The initial installation requires replacing your existing skimmer faceplate with the Aquador faceplate using a screwdriver, which is best done when the water is slightly lowered. Once the faceplate is installed, the winter lid simply snaps on and off without tools each season.

This is a game-changer for above-ground pool owners who want to avoid draining their pools below the skimmer line, but it is not compatible with certain custom molded concrete skimmer designs.

How to Properly Blow Out Pool Lines Before Winter

Blowing out your pool lines is the single most important step in preventing catastrophic freeze damage to underground plumbing. Start by hooking up a high-volume air blower or a heavy-duty shop vacuum to your pool equipment pad, typically at the pump strainer basket or chlorinator. Turn on the blower to push air through the lines, forcing all the standing water out through the return jets and skimmers.

Once you see a steady stream of air bubbles blasting out of a return jet, quickly insert an expansion plug into that line while the air pressure is still active to seal it tight. Repeat this process for each return line, working from the closest line to the pump to the furthest. Finally, blow out the main drain line at the bottom of the pool until you see a massive eruption of bubbles, then quickly close the slide valve at the equipment pad to create an airtight lock.

After sealing the lines, pour a pool-safe antifreeze down the skimmer line as a secondary safety measure before inserting your Gizzmo or skimmer plug. This ensures that any tiny amounts of moisture that seep past the plugs cannot expand and damage your plumbing. Double-check all plugs for tight seals before putting the pool cover on for the winter.

Conclusion

Investing the time and choosing the right winterization supplies today saves you from costly repairs and massive headaches when warm weather returns. By properly sealing your lines, balancing your water, and shielding your pool from the elements, you ensure a stress-free spring opening. Take control of your off-season maintenance now, and look forward to a seamless transition back to crystal-clear water next summer.