Winterizing a Pool: 9 Essential Supplies to Buy

As autumn leaves begin to drop and temperatures take a sharp dip, the reality of seasonal pool closing sets in. Neglecting this transition turns a crystal-clear oasis into a costly, cracked nightmare come spring. Having the right tools on hand turns a daunting multi-day chore into a streamlined weekend project that safeguards your backyard investment.

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Why Proper Winterization Saves Your Pool for Spring

Water expands by about nine percent when it freezes, exerting immense pressure on everything it touches. In a swimming pool, this expansion can crack rigid PVC pipes, rupture skimmer throats, and tear pool liners. A proper winterization routine keeps these forces in check by removing water from vulnerable areas and neutralizing the chemistry of what remains.

Beyond mechanical protection, proper winterization prevents the dreaded green-water opening. Algae and mold thrive in stagnant, untreated water as soon as the weather warms up in early spring. Sealing the pool correctly ensures that opening day is a simple matter of uncovering, balancing, and swimming, rather than weeks of scrubbing and expensive chemical shock treatments.

Safety Cover – Loop-Loc Brass Anchor Safety Cover

A safety cover is the ultimate line of defense for an inground pool during the off-season. Unlike standard tarps, it acts as a drum-tight barrier that prevents leaves, twigs, and accidental falls from breaching the pool water. It utilizes heavy-duty tension straps anchored directly into your pool deck to maintain structural integrity.

The Loop-Loc Brass Anchor Safety Cover stands out because of its legendary strength and precise fit. Constructed from high-density polypropylene mesh, it allows rain and melting snow to drain through while blocking ultra-fine debris and sunlight that fuels algae growth. The flush-mount brass anchors thread down level with the deck when the cover is removed, eliminating stubbed toes during the swimming season.

• Material: Superdense mesh (blocks virtually all sunlight)
• Weight Capacity: Engineered to support the weight of multiple adults
• Hardware: Corrosion-resistant brass anchors and stainless steel springs
• Best For: Inground concrete, pavers, or wood decks

Before purchasing, accurate measurements are non-negotiable. Custom-shaped pools require precise triangulation measurements to ensure the strap anchors line up correctly. This cover is perfect for homeowners seeking long-term durability and peace of mind, though it is not suitable for above-ground pools without custom deck installations.

Winterizing Chemical Kit – In The Swim Winter Pool Kit

Closing a pool with unbalanced chemistry guarantees a swampy mess when the cover comes off. A dedicated winterizing kit provides a concentrated, slow-release blend of chemicals designed to function in cold water. These chemicals prevent staining, neutralize scale build-up, and suppress algae growth over months of dormancy.

The In The Swim Winter Pool Kit is the gold standard for off-season water preservation. It includes a combination of non-chlorine shock to oxidize contaminants, a powerful winter algaecide, a metal chelating agent to prevent rust stains, and a unique slow-release chemical floater. This floater sanitizes the water continuously as temperatures fluctuate throughout the winter.

• Sizing Options: Kits available for pools up to 10k, 20k, and 35k gallons
• Chemicals Included: Winterizer, Algaecide, Metal Free, and Winter Floater
• Compatibility: Safe for all pool types, including vinyl, plaster, and fiberglass

Always run the filtration system for at least four to six hours after adding these chemicals to ensure uniform distribution before lowering the water level. This kit is ideal for any pool owner wanting a pre-measured, hassle-free chemical regimen. It is not designed to clear up an already-green pool, so clean the water thoroughly before applying the kit.

Pool Cover Pump – Little Giant APCP-1700 Cover Pump

Accumulated rainwater and melted snow can weigh down a solid pool cover, stretching the material and pulling it into the pool. A cover pump automatically evacuates this standing water before it becomes a structural hazard. Without one, you risk ruining a costly cover or drowning your safety anchors under tons of extra weight.

The Little Giant APCP-1700 Cover Pump is a workhorse engineered specifically for this harsh task. It features an integrated automatic switch that activates the pump when water reaches two inches and deactivates it once the water drops to 1.5 inches. Its robust motor moves up to 1,700 gallons of water per hour, quickly clearing even the heaviest rainstorms.

• Flow Rate: 1,700 Gallons Per Hour (GPH)
• Power Cord Length: 25 feet
• Discharge Connection: Standard 3/4-inch garden hose thread
• Key Feature: Removable intake screen for easy cleaning

Keep in mind that wet autumn leaves can clog the intake screen, requiring occasional clearing during heavy leaf drops. This pump is a must-have for solid tarp covers and solid safety covers. It is unnecessary for standard mesh safety covers, which naturally allow water to filter through into the pool below.

Pool Air Pillow – Robelle Ice Equalizer Pillow

Above-ground pools face a unique threat: ice expansion can push outward against the pool walls, causing structural collapse. An air pillow sits in the center of the pool under the cover, acting as an expansion cushion. When the water freezes, the ice compresses the pillow inward rather than pushing outward against the fragile pool walls.

The Robelle Ice Equalizer Pillow is built from heavy-duty, puncture-resistant vinyl designed to survive extreme sub-zero conditions. It features a reliable, leak-resistant air valve that prevents deflating under heavy snow loads. By raising the center of the cover slightly, it also helps funnel rainwater and melting snow toward the edges of the pool for easier removal.

• Material: 16-gauge heavy-duty vinyl
• Standard Size: 4 x 4 feet and 4 x 15 feet options
• Attachment Points: Reinforced corner grommets for securing ropes

The most common mistake is inflating the pillow to 100 percent capacity. Only inflate it to about 60 to 80 percent of its volume to leave room for ice compression without popping the seams. This is an essential safety item for above-ground pool owners, while inground owners generally do not require one.

Winter Expansion Plug – Anderson Winterizing Plug

Once pool lines are cleared of water, they must be sealed air-tight to prevent water from creeping back in and freezing. Expansion plugs slip into return jets and cleaner lines, expanding to create a watertight seal when tightened. A faulty plug allows water to seep back into underground pipes, leading to catastrophic freeze damage.

The Anderson Winterizing Plug features premium-grade neoprene rubber that resists chemicals, ozone, and cold weather cracking. Its heavy-duty stainless steel bolt and wing nut design makes installation simple and tool-free. As the wing nut turns, the rubber compression sleeve expands uniformly against the inner walls of the pipe, ensuring a flawless seal.

• Material: Chemical-resistant neoprene rubber with stainless steel hardware
• Available Sizes: Standard sizes ranging from 0.5 inches to 2 inches
• Usage: Returns, main drains, skimmers, and cleaner lines

Always measure the internal diameter of your return fittings before ordering, as a loose plug will fail under pressure. This plug is perfect for DIY pool owners who want professional-grade security in their plumbing lines. It is not suitable for threaded fittings that require specific male-threaded plugs.

Skimmer Guard – Gizzmo Ultra Skimmer Freeze Plug

Your pool’s skimmer is a delicate plastic housing recessed into the pool wall, making it highly vulnerable to cracking when trapped water freezes. A skimmer guard threads into the bottom of the skimmer throat to seal off the pipe while absorbing ice expansion inside the skimmer well. If ice forms inside the skimmer, it compresses the guard rather than cracking the expensive plastic housing.

The Gizzmo Ultra Skimmer Freeze Plug is the industry standard for skimmer protection. It features a hollow, heavy-duty plastic body designed to collapse safely under the crushing pressure of expanding ice. The Gizzmo also features built-in double threads on the bottom to seal 1.5-inch and 2-inch skimmer lines simultaneously.

• Size: 16 inches in length
• Thread Compatibility: Dual threads fit 1.5-inch and 2-inch internal threads
• Design: Blow-molded plastic with a built-in pressure relief chamber

To ensure a completely watertight seal, wrap the threads of the Gizzmo with a few layers of Teflon tape before screwing it into the skimmer. This product is an absolute necessity for inground pools in areas that experience deep freezes. It is not designed for above-ground skimmers, which are typically disconnected and drained entirely for the winter.

How to Properly Blow Out Your Pool Lines for Winter

Blowing out the plumbing lines is the most critical step in preventing underground pipe ruptures. To start, lower the pool water level below the skimmer mouth using your filtration pump or a submersible pump. Attach a powerful commercial air blower or a heavy-duty shop vacuum to the pool lines at the equipment pad, typically through the pump strainer basket or filter.

Turn on the blower and watch the pool return jets; you will see a massive rush of water followed by a steady stream of air bubbles. While the air is blowing vigorously, insert your expansion plugs into the return fittings one by one, starting with the line closest to the pump. This creates an air lock that keeps water from re-entering the pipes.

Finally, blow out the skimmer line and screw in your Gizzmo plug quickly while air pressure is maintained. For the main drain at the bottom of the pool, blow air until a massive geyser of bubbles erupts in the deep end, then quickly close the valve at the equipment pad to lock in the air column. This air lock prevents water from rising back up the pipe, keeping it safe from freezing temperatures.

Pool Antifreeze – In The Swim Non-Toxic Antifreeze

Even a thorough blowout can leave trace amounts of water trapped in low points of your underground plumbing. Pool antifreeze acts as a secondary insurance policy, preventing any remaining water from freezing and cracking the pipes. It is poured directly into the plumbing lines after they have been blown out and plugged.

In The Swim Non-Toxic Antifreeze is formulated specifically for pool plumbing using non-toxic propylene glycol. Unlike automotive antifreeze, which is highly toxic and will ruin your pool’s chemistry, this formula is safe for the environment and swimming pool components. It prevents water from freezing down to temperatures as low as minus 40 degrees Fahrenheit.

• Base Ingredient: 100% non-toxic propylene glycol
• Temperature Rating: Protects down to -40°F (-40°C)
• Safety: Eco-friendly, safe for pets, and compatible with all pool types

Do not add this antifreeze directly to your pool water; it is strictly meant for the interior of the plumbing lines. It is ideal for pool owners in northern climates who experience prolonged, hard freezes. It is not necessary for pool owners in mild climates where temperatures rarely drop below freezing.

Pool Cover Water Bag – Robelle Double Water Chamber

If you use a traditional solid tarp cover instead of a safety cover, you need a reliable method to hold the edges down against the wind. Water bags sit along the perimeter of the pool deck, weighting the cover edges flat to prevent wind from getting underneath. Using bricks or concrete blocks can tear the cover and damage your pool deck, making water bags the safest choice.

The Robelle Double Water Chamber is engineered to stay put on your pool deck without rolling. Its double-chamber design ensures that if one side punctures or freezes, the other chamber remains filled to hold the cover in place. Made from heavy-gauge, puncture-resistant vinyl, it is built to survive the expansion of freezing water inside the bags.

• Material: Heavy-duty, UV-stabilized vinyl
• Chamber Style: Dual-chamber (prevents rolling and provides redundancy)
• Standard Lengths: Available in 8-foot and 10-foot lengths

When filling these bags, only fill them halfway to two-thirds full to allow room for the water to expand as it freezes into ice. Filling them completely will pop the seams during the first hard freeze. This product is essential for inground pool owners using tarp covers, but completely unnecessary for those with anchor-style safety covers.

Pool Leaf Net Cover – Blue Wave Bronze Leaf Net

Deciduous trees can dump a massive volume of wet, heavy leaves onto your pool cover in late autumn. These leaves rot into a heavy, acidic sludge that is incredibly difficult to remove in the spring. A leaf net cover sits on top of your main winter cover, catching these leaves before they can decay.

The Blue Wave Bronze Leaf Net features a lightweight, durable woven polyethylene mesh with a generous overlap to secure it in place. Once all the leaves have fallen from the surrounding trees, you simply peel the leaf net off, leaving your main cover clean and dry. It features a heavy-duty ratchet and cable system to keep it taut against the wind.

• Material: Woven polyethylene mesh
• Overlap: 4-foot overlap to ensure complete coverage
• Hardware: Includes vinyl-coated steel cable and metal winch

It is vital to remove the leaf net before the first major snowfall of the season. Leaving a leaf-filled net under a heavy snow load will make it too heavy to lift and can damage the underlying cover. This is a game-changing tool for pool owners with heavy tree canopy, but skip it if your yard is open and free of deciduous trees.

Mid-Winter Maintenance Tasks You Cannot Ignore

Winterizing is not a “set-and-forget” process; a pool still requires periodic monitoring during the cold months. Check your cover tension monthly to ensure safety springs are not overstretched and anchors remain flush. High winds and heavy snow can shift covers, creating gaps that let dirt and sunlight enter the pool.

Monitor the water level beneath the cover periodically using a flashlight through a peek-hole or corner. If a slow leak develops in your liner or plumbing, the water level will drop, removing the structural support your cover needs. This can cause a safety cover to collapse under a heavy snow load, causing massive damage.

Keep an eye on the accumulation of water on solid covers and run your cover pump whenever temperatures rise above freezing. Clearing off heavy snow and ice buildup minimizes stress on the pool walls and cover seams. These simple checks take less than fifteen minutes but save thousands of dollars in potential off-season damage.

Conclusion

Taking the time to close your pool with the right supplies ensures that freezing winter temperatures do not compromise your backyard oasis. Investing in high-quality plugs, pumps, and covers saves valuable time and money when the warm weather returns. Equip yourself with these essentials, execute a thorough closing routine, and enjoy a stress-free winter knowing your pool is fully protected.