9 Essential Winterization Supplies For Your Inground Pool

As autumn leaves begin to fall and the summer heat fades into memory, pool owners must shift their focus from recreation to preservation. Skipping or rushing the winterization process turns a backyard oasis into a ticking time bomb of cracked pipes and ruined plaster. Having the right tools on hand now ensures that reopening the pool next spring is a seamless, stress-free celebration rather than an expensive rescue mission.

Disclosure: As an Amazon Associate, this site earns from qualifying purchases. Thank you!

Why Proper Winterization Prevents Costly Spring Repairs

Freezing water is incredibly destructive because it expands by nearly nine percent, exerting thousands of pounds of pressure on everything containing it. In an inground pool, this expansion happens inside underground PVC plumbing lines, delicate filtration valves, and the concrete skimmer well. Without proper winterization, a single hard freeze can crack these components, leading to thousands of dollars in underground leak repairs come spring.

Beyond mechanical damage, failing to properly seal and treat the water over the winter invites organic disaster. Unprotected pool water becomes a breeding ground for stubborn black and mustard algae, which can permanently stain vinyl liners and plaster finishes. Investing in the right winterization gear now is simply insurance against the inevitable, brutal forces of winter.

Winter Pool Cover – Loop-Loc Safety Pool Cover

A winter pool cover does far more than keep dry leaves out of the water; it is a critical safety barrier that prevents accidental drownings while blocking the sunlight that fuels algae growth. Cheap tarps weighed down by water blocks frequently fail under heavy snow loads, dumping dirty water and organic debris straight into the pool. A tension-secured safety cover stays taut and professional-looking all winter long, handling heavy snow and ice with ease.

The Loop-Loc Safety Pool Cover stands out because of its legendary strength, utilizing ultra-tough mesh that allows rainwater to pass through while trapping the finest debris. Its brass anchors recess flush into the concrete deck when not in use, meaning there are no tripping hazards during pool season. The heavy-duty stainless steel springs stretch to absorb immense weight, giving pool owners absolute peace of mind during severe winter storms.

• Material: Super dense mesh or solid vinyl options
• Break Strength: Exceeds ASTM safety standards
• Hardware: Brass anchors, stainless steel springs, and installation tool included

Installation requires drilling anchor holes directly into a concrete, brick, or wood deck, which requires a rotary hammer drill and careful measurement. The tension springs require a specific installation rod to stretch onto the anchors, requiring some physical strength during the initial setup. This cover is the gold standard for families with children, pets, or heavy snow climates, though it is not suitable for pools lacking a solid deck perimeter for anchoring.

Pool Cover Pump – Little Giant APCP-1700 Automatic

Solid winter covers and tarps inevitably collect rain and melting snow, creating heavy pools of water that can stress the cover material and pull anchors out of the deck. Leaving standing water on a cover also creates an ugly, stagnant breeding ground for mosquitoes in the early spring. An automatic cover pump solves this by safely and continuously evacuating water before it can accumulate and cause structural damage.

The Little Giant APCP-1700 Automatic Pool Cover Pump is the industry workhorse for this task, activating automatically when water levels reach two inches and shutting off once the cover is dry. Its wide, stable base prevents the pump from tipping over on uneven cover surfaces, while the integrated handle makes it easy to position using a pool pole. Powered by a highly efficient motor, it quickly clears up to 1,700 gallons per hour using a standard garden hose connection.

• Flow Rate: Up to 1,700 Gallons Per Hour (GPH)
• Activation: Automatic switch at 2 inches of water, deactivates at 0.5 inches
• Power Cord: 25-foot heavy-duty power cord
• Connection: Fits standard 3/4-inch garden hoses

Users must regularly clear fallen leaves from around the intake screen, as heavy debris can clog the suction grid and cause the motor to overheat. It is also important to store the pump indoors during prolonged deep freezes to prevent ice from damaging the internal impeller housing. This pump is a must-have for solid cover users, but it is unnecessary for those utilizing standard mesh safety covers that naturally drain into the pool.

Winterizing Kit – In The Swim Deluxe Closing Kit

Simply throwing a cover over dirty, chemically unbalanced water ensures a green, foul-smelling mess when the cover comes off in the spring. A winterizing chemical kit provides a slow-releasing defense system that keeps the water clear, prevents algae spores from taking root, and protects pool walls from staining. Using a pre-packaged kit removes the guesswork, ensuring the pool receives the exact ratio of chemicals needed for months of dormancy.

The In The Swim Deluxe Closing Kit is highly favored because it contains pre-measured doses of high-quality winter shock, a specialized winterizer algaecide, and a metal control agent to prevent scale. The star of the kit is the patented winter floating dispenser, which slowly releases a non-chlorine sanitizer to keep the water sparkling even as temperatures fluctuate in early spring. These chemicals are formulated to remain stable in cold temperatures without damaging vinyl liners or plaster finishes.

• Pool Capacity: Kits sized for pools up to 10,000, 22,000, or 35,000 gallons
• Kit Contents: Chlorine-free winter shock, winterizer algaecide, metal-free stain preventer, and a winter floating sanitizer dispenser
• Compatibility: Safe for all pool types, including vinyl liner, fiberglass, and plaster

For these chemicals to work effectively, the pool’s pH, total alkalinity, and calcium hardness must be fully balanced several days before adding the kit. The pool pump must run for at least four to six hours after adding the chemicals to ensure complete distribution throughout the water column before shutting down the system. This kit is ideal for any pool owner looking for an easy, all-in-one chemical solution, but owners of massive custom pools over 35,000 gallons will need to purchase multiple kits or extra individual supplements.

Expansion Plugs – Blue Devil Rubber Freeze Plugs

Once water is successfully purged from the pool’s underground plumbing lines, those lines must be sealed airtight to prevent water from creeping back in. If water slips past a weak seal, it will settle in the pipes, freeze, and crack the underground PVC. Heavy-duty rubber expansion plugs act as a mechanical barrier, expanding inside the pipe opening to create a permanent, watertight seal that resists winter pressure.

Blue Devil Rubber Freeze Plugs are the industry standard because of their chemical-resistant rubber construction and non-corrosive stainless steel wingnuts. The ribbed rubber body prevents the plug from slipping out of wet PVC pipes, even when subjected to backpressure from air or freezing water. The oversized wingnut makes it simple to tighten the plug securely by hand without needing specialized, awkward tools inside the pool.

• Material: Heavy-duty ribbed rubber with stainless steel hardware
• Available Sizes: Standard sizes from #6 (1-inch) to #11 (2-inch), with #10 (1.5-inch) being the most common
• Seal Type: Mechanical expansion via wingnut tightening

Before purchasing, pool owners must verify the exact inner diameter of their return lines, as a plug that is too small will blow out under pressure, while one that is too large will not fit into the pipe threads. Over-tightening the wingnut can split older, brittle plastic fittings, so hand-tightening until snug is the recommended approach. These plugs are an absolute necessity for anyone winterizing an inground pool with submerged return jets, but they are not a substitute for proper line blowing.

Skimmer Guard – Gizzmo Ultra Freeze Protection

The skimmer well is one of the most vulnerable parts of an inground pool because water naturally collects there, and its rigid plastic walls are encased in solid concrete. When this water freezes, it expands outward, easily cracking the skimmer body and leading to incredibly expensive deck-demolition repairs. A skimmer guard solves this problem by acting as a sacrificial lamb, absorbing the crushing force of the expanding ice.

The Gizzmo Ultra Freeze Protection device is a brilliant two-in-one tool that plugs the skimmer line while protecting the skimmer throat from ice damage. Its hollow, heavy-duty plastic body is designed to collapse inward when ice forms around it, safely absorbing the expansion pressure. The Ultra model features dual threads on the bottom, allowing it to screw directly into either 1.5-inch or 2-inch skimmer plumbing lines for a perfectly sealed fit.

• Length: 16 inches for deep skimmer wells
• Thread Sizes: Dual threads (1.5-inch and 2-inch tapered male threads)
• Design: Hollow, collapsible plastic cylinder with built-in blow-through capability

To ensure an airtight seal and prevent the threads from binding, apply a few wraps of Teflon tape to the Gizzmo’s male threads before screwing it into the skimmer. If your pool has a very shallow skimmer throat, check clearances first, as the 16-inch Ultra model may prevent your skimmer lid from sitting flush. This product is a non-negotiable insurance policy for any northern pool owner, though it is redundant for those in southern climates that never experience hard, sustained freezes.

Pool Antifreeze – Splasher’s Non-Toxic Antifreeze

Even after using a powerful line blower, tiny pockets of water and condensation can still pool in low points of underground PVC lines. If a severe freeze strikes, these small pools of water can freeze, expand, and rupture the pipe from the inside out. Specially formulated pool antifreeze acts as a vital safety net, mixing with any residual water to lower its freezing point and prevent ice formation.

Splasher’s Non-Toxic Antifreeze utilizes high-purity propylene glycol to deliver reliable freeze protection down to -50°F. Unlike toxic automotive antifreeze, this formula is completely safe for swimmers, pets, and local wildlife when the pool is opened and discharged in the spring. It is chemically engineered to be non-corrosive, meaning it will not degrade copper connections, rubber gaskets, or PVC plumbing over the long winter months.

• Chemical Base: Propylene Glycol (non-toxic, eco-friendly)
• Freeze Protection: Rated down to -50°F (-45°C)
• Compatibility: Safe for all copper, PVC, and flexible plastic pipes

It is critical to remember that pool antifreeze must never be added directly to the main pool water; instead, pour it directly into the skimmer, return lines, or main drain plumbing. Always ensure the lines have been blown out as much as possible first, as excess water will dilute the antifreeze and raise its freezing point. This product is highly recommended for anyone in the Rust Belt or northern climates, while pool owners in mild climates can safely bypass it.

Line Blower – Cyclone Pro Pool Line Bypass Blower

Successfully purging water from deep underground plumbing lines—especially the main drain at the bottom of the pool—requires massive air volume and consistent pressure. Standard household shop vacuums simply lack the power to push water up and out of deep pipes, often leaving dangerous pockets of water behind. A dedicated pool line blower is the single most critical tool for ensuring your pipes are bone-dry before the ground freezes solid.

The Cyclone Pro Pool Line Bypass Blower is the ultimate professional-grade tool for this task, utilizing a robust 3.0 horsepower motor to generate incredible airflow. Unlike standard vacuums that can overheat when air restriction occurs, its bypass motor design allows air to cool the motor even when lines are completely blocked. It produces up to 5.5 PSI of pressure, which is more than enough to blow out stubborn main drains and complex multi-port manifold systems with ease.

• Motor Power: 3.0 Horsepower bypass motor
• Airflow Rating: 130 CFM (Cubic Feet per Minute) at 5.5 PSI
• Hose Connection: 2-inch quick-connect hose with various adapter fittings included

Because this blower draws a high amount of electrical current, it should be plugged directly into a dedicated 20-amp GFCI outlet or used with a heavy-duty, low-gauge extension cord to prevent voltage drops. The unit comes with a flexible hose and stepped adapters, but users may need to purchase specific threaded quick-connect fittings to match their pump or skimmer threads. This is an essential investment for any pool owner looking to bypass expensive professional closing fees, but it is unnecessary for those who plan to hire out their pool winterization every year.

Water Bags – In The Swim Double Chamber Water Tubes

For pools without safety cover anchor systems, keeping a standard winter tarp cover secured against the howling winter wind is a constant struggle. If wind gets underneath the cover, it can lift the entire tarp, exposing the water and dumping heavy debris into the pool. Heavy-duty vinyl water bags are designed to lay flat along the pool perimeter, keeping the cover edges firmly pressed against the deck.

In The Swim Double Chamber Water Tubes are engineered specifically to avoid the common failures of cheap, single-chamber bags. The double-chamber design ensures that the tube lays completely flat and won’t roll off the deck, even on sloped perimeters. Made from puncture-resistant 18-gauge vinyl, these tubes feature leak-proof valves that seal tightly to prevent water loss throughout the winter months.

• Material: Heavy-duty, puncture-resistant 18-gauge vinyl
• Design: Double-chamber construction to prevent rolling
• Length Options: Available in 8-foot and 10-foot lengths

A critical mistake when using these tubes is filling them completely to the top; they should only be filled 60% to 70% full of water. This empty space gives the water room to expand when it freezes into solid ice, preventing the vinyl from splitting open along the seams. These tubes are an absolute must for anyone using a traditional weighted tarp cover, but they serve no purpose for those with modern spring-anchored safety covers.

Skimmer Cover – Aquador 1090 Winter Skimmer Lid

Traditionally, winterizing a pool meant draining the water level several inches below the skimmer mouth to prevent water from entering the plumbing. However, lowering the water level too much can cause vinyl liners to shrink, dry out, or pull away from the walls, leading to structural damage. A snap-on skimmer faceplate cover seals the skimmer opening from inside the pool, allowing the water level to remain high and stable all winter.

The Aquador 1090 Winter Skimmer Lid is a game-changer, featuring a flexible, freeze-resistant snap-on lid that creates a 100% watertight seal over the skimmer mouth. By keeping the pool water at its normal operating level, the pool liner remains properly weighted and stretched, preventing unsightly shifting or wrinkling. Once the Aquador lid is snapped in place, the skimmer well itself can be completely drained and dried, protecting the plastic housing from ice expansion.

• Model Compatibility: Fits standard Aquador 1090 faceplates (standard size skimmers)
• Material: UV-resistant, chemical-resistant flexible plastic
• Seal Type: Snap-on, watertight perimeter seal

To use this system, the pool owner must initially replace their standard skimmer faceplate with the specially designed Aquador faceplate during the swimming season. After that initial one-time installation, winterizing is as simple as snapping the plastic lid onto the faceplate each autumn. This cover is highly recommended for vinyl liner pool owners looking to preserve their liner’s lifespan, but it is not compatible with certain commercial or custom-molded concrete skimmer systems.

How to Safely Blow Out Inground Pool Plumbing Lines

Blowing out pool plumbing lines is the most critical step of the entire winterization process, requiring a methodical approach to ensure no water remains in the pipes. Start by lowering the pool water level if not using a skimmer faceplate cover, then hook up your line blower to the pump basket drain plug or the skimmer line. Turn the multi-port valve to the “Recirculate” position to bypass the filter tank, ensuring you do not damage the delicate internal lateral fingers of your filter.

Turn on the blower and open the valves to the return lines one by one, allowing the air to push the water out until you see a violent geyser of air bubbles emerging from the pool wall. Quickly insert a rubber expansion plug into the bubbling return jet and tighten it securely while the air is still blowing to prevent water from rushing back in. Once the return lines are sealed, repeat this process for the main drain, looking for a massive burst of air at the bottom of the pool before quickly closing the main drain valve at the pad to lock in the air lock.

Finally, blow out the skimmer lines and secure them with a Gizzmo or expansion plugs, then turn off the line blower. Pour a generous amount of non-toxic pool antifreeze down the lines as a final safety measure against any residual condensation. Taking your time during this process ensures that every inch of underground PVC remains bone-dry and completely immune to the crushing forces of freezing soil.

When is the Ideal Time to Close Your Pool for Winter

Timing your pool closing is a balancing act that directly impacts how clean your water will be when spring arrives. Closing the pool too early, while daytime temperatures are still regularly reaching the 70s, is a recipe for disaster. Warm water rapidly depletes pool chemicals and winter shock, allowing algae to bloom underneath the cover for weeks before the true cold weather sets in.

The ideal time to close your pool is when the water temperature consistently drops below 65°F (18°C) and stays there. At this temperature, algae spores become dormant, meaning your winter chemicals will remain highly effective and keep the water pristine until spring. However, do not wait until the first hard freeze is forecast, as trying to blow out plumbing lines with freezing fingers and icy water is a miserable—and risky—endeavor.

Conclusion

Taking the time to properly winterize an inground pool with the right gear is the ultimate investment in your property’s longevity. By systematically blowing out the lines, balancing the chemistry, and securing a heavy-duty cover, you guarantee a hassle-free spring reopening. When the warm weather returns, the pool will be ready to transition from a dormant winter sleep back to a vibrant summer sanctuary with minimal effort.