9 Essential Winterizing Supplies for Your Inground Swimming Pool

As autumn leaves begin to fall and the summer heat fades, pool owners face the inevitable task of closing down their backyard oasis for the cold months ahead. Skipping or rushing through this seasonal transition is a recipe for cracked pipes, ruined liners, and a green swamp come spring. Equipping yourself with the right winterization gear now ensures your inground pool survives the harsh freezing temperatures and remains protected until the first warm day of next year.

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Why Proper Winterization Prevents Costly Spring Repairs

Freezing water expands by about nine percent, exerting immense force on anything trapping it. Inside rigid PVC underground plumbing lines, this expansion causes clean, catastrophic splits that require excavation to repair. Protecting these buried assets requires a systematic approach to clearing water and sealing the system.

Beyond plumbing, stagnant, untreated pool water becomes a breeding ground for algae and staining minerals over a six-month slumber. Without the right chemical balance and physical barriers, winter precipitation will dilute your pool chemistry and ruin the finish. Proper winterization is essentially insurance against expensive renovation bills when the swim season returns.

Pool Safety Cover – Loop-Loc Green Mesh Cover

A safety cover does more than keep leaves out; it prevents accidental drownings and handles heavy snow loads without collapsing into the pool. Traditional solid tarps require heavy water bags and constant pumping, whereas a tensioned mesh cover anchors directly into the deck. This physical barrier keeps the pool secure while allowing rainwater to drain through, preventing dangerous water accumulation on top.

The Loop-Loc Green Mesh Cover is the industry standard for a reason, utilizing super-strong, polyester-bonded thread and double-perimeter webbing. Its mesh design filters out debris down to microscopic sizes while letting water pass through easily, meaning no heavy lifting or pumping off accumulated rainwater. The brass anchors sit flush with the concrete deck when not in use, maintaining a clean, trip-free perimeter.

• Material: Ultra-strong, lightweight mesh that allows water drainage
• Tensile Strength: Exceeds ASTM safety standards for weight capacities
• Included Hardware: Brass anchors, stainless steel springs, installation tool
• Warranty: 15-year pro-rated manufacturer warranty

Before buying, note that this cover requires a concrete deck or specific lawn anchors for proper tensioning. If the pool has unique rock features or raised spas, a custom-cut cover is necessary rather than a standard rectangular size. This cover is perfect for homeowners looking for absolute safety and low-maintenance winters, but it may not be ideal for those with heavy silt or fine dust environments where a solid cover performs better.

Pool Cover Pump – Little Giant APCP-1700

If you use a solid cover or if rainwater pools on top of your safety cover’s tension points, you need a reliable way to remove it. Left unchecked, thousands of pounds of standing water can stretch springs, tear vinyl liners, or create a hazardous drowning puddle for local wildlife. A submersible cover pump automates this chore by activating whenever water reaches a certain level.

The Little Giant APCP-1700 is designed specifically for this harsh environment, featuring an integrated mechanical float switch that activates automatically. Delivering up to 1,745 gallons per hour, it quickly clears heavy downpours before water weight can damage your pool structure. The wide, weighted base keeps the pump upright and stable, even when surrounded by wet, slippery leaves.

• Flow Rate: 1,745 GPH at a 0-foot lift height
• Activation Point: Automatically turns on in 2 inches of water, shuts off at 0.75 inches
• Power Cord: 25-foot heavy-duty power cord for easy outlet access
• Discharge Connection: Standard 3/4-inch garden hose thread

Keep in mind that while this pump handles small debris, leaves can clog the intake screen over time, requiring occasional clearing during heavy autumn shedding. It must also be removed and stored indoors before deep, sustained freezes to prevent the internal pump housing from cracking. It is the ultimate choice for solid-cover users and high-precipitation regions, but overkill for arid climates with minimal winter rain.

Skimmer Guard – Gizzmo Ultra Freeze Protection

Your pool’s skimmer is especially vulnerable to winter damage because it sits right at the freeze line. As ice expands inside the skimmer throat, it can easily crack the plastic housing, leading to a massive, difficult-to-repair leak behind the pool wall. A skimmer guard acts as a sacrificial compression chamber, absorbing the expansion forces of freezing water.

The Gizzmo Ultra Freeze Protection is a heavy-duty, blow-molded plastic tube designed to screw directly into the skimmer’s bottom threads. Its hollow, collapsible design is engineered to deform under ice pressure, collapsing inward so your expensive skimmer throat does not have to. Featuring a 1.5-inch and 2-inch double-threaded style, it fits almost any standard inground pool skimmer port without needing adapters.

• Length: 16 inches for deep freeze protection
• Thread Sizes: Dual 1.5-inch and 2-inch tapered threads
• Material: High-density, freeze-resistant polymer
• Special Feature: Built-in blow-out channel to assist with line clearing

Ensure you wrap the threads with Teflon tape before installation to guarantee an airtight seal and prevent water from seeping back into the plumbing lines. This tool is a non-negotiable requirement for pool owners in climates that experience hard, deep freezes. It is not necessary for warm climates where winter temperatures rarely drop below freezing for more than a few hours.

Winter Expansion Plug – Anderson Winterizing Plug

Once you blow the water out of your return lines, you must seal them tight to prevent water from creeping back in. Standard rubber expansion plugs can slip, degrade, or pop out under pressure, risking catastrophic freeze damage to the plumbing. A high-quality, mechanical expansion plug creates a positive, airtight seal inside the pipe wall.

The Anderson Winterizing Plug utilizes heavy-duty, chemical-resistant rubber and a durable nylon wing nut that will not rust or seize over the winter. Its patented design expands evenly against the inner walls of the schedule 40 PVC pipe, creating an airtight barrier that resists high backpressure. These plugs are built to withstand freeze-thaw cycles year after year without cracking or losing their elasticity.

• Material: Marine-grade rubber with heavy-duty nylon hardware
• Sizes Available: 1.5-inch, 2-inch, and custom step-down sizes
• Application: Pool return jets, main drains, and cleaner lines
• Durability: UV-resistant and pool-chemical-tolerant construction

Always measure your return line openings carefully before purchasing, as some pool builders use non-standard fittings or threaded step-downs. Tighten these plugs snugly by hand; over-tightening with tools can crack aged plastic return fittings. These are essential for any inground pool owner blowing out their own lines, though those with simple, non-freezing climates can opt for basic rubber stoppers.

Winter Chemical Kit – In The Swim Ultimate Kit

Closing your pool with balanced water is only half the battle; those chemicals must endure six months of cold, dark stagnation. Without a sustained chemical presence, algae spores will bloom the moment the water warms up in early spring, turning your pool into a costly cleaning nightmare. A dedicated winter chemical kit slowly releases sanitizer and stain preventers throughout the off-season.

The In The Swim Ultimate Kit contains a pre-measured regimen of winterizing pool shock, non-chlorine oxidizer, winter algaecide, and a slow-release winter floater. This combination prevents staining from metals, keeps algae at bay, and eliminates organic contaminants without bleaching vinyl liners. It is formulated to perform in cold water, ensuring the chemicals do not precipitate out and settle on the pool floor.

• Pool Size Capacity: Kits available for pools up to 10,000, 22,000, and 35,000 gallons
• Kit Components: Winterizing powder shock, winter algaecide, stain away, and floating chemical dispenser
• Chemical Base: Non-staining, cold-water-active formulas
• Compatibility: Safe for vinyl, plaster, fiberglass, and painted surfaces

Remember that these kits are designed to preserve already clean, balanced water, not to cure a swampy pool right before closing. Run your pool filter for at least four to six hours after adding these chemicals to ensure thorough distribution. This kit is ideal for busy pool owners who want a foolproof, all-in-one chemical solution for a clear spring opening.

Pool Line Blower – Cyclone 3 HP Bypass Blower

Leaving even a small amount of water inside underground plumbing lines invites ice damage that can cost thousands of dollars to excavate and repair. Standard shop vacuums simply lack the head pressure required to push water out of deep main drains and long plumbing runs. A dedicated pool line blower delivers high-volume, low-pressure air to purge water completely from the system.

The Cyclone 3 HP Bypass Blower is the gold standard for pool professionals, providing the massive volume of air needed to clear 2-inch lines with ease. It features a bypass motor design that prevents overheating even when backpressure builds up during line clearing. Its durable plastic housing is impact-resistant, making it tough enough to handle the wear and tear of poolside operation.

• Motor Size: 3.0 HP bypass motor
• Airflow Output: 130 CFM at open flow
• Hose Connection: 1.5-inch threaded outlet with a flexible quick-connect hose
• Weight: Lightweight and portable at under 15 pounds

Operating this blower requires a basic understanding of your pool’s plumbing manifold and valve positioning to prevent blowing out pump seals. It works best when connected directly to the skimmer or the pump intake housing. While it represents a larger upfront investment, this tool is perfect for the serious DIY pool owner who wants to stop paying pool companies hundreds of dollars for annual closings.

Pool Antifreeze – Splash Pool and Spa Antifreeze

Even after blowing out your plumbing lines, condensation and slow groundwater seepage can slowly find their way back into your pipes. If this residual water freezes, it can still split underground pipes or crack pool valves. Adding a dedicated, non-toxic antifreeze provides a crucial secondary layer of defense for your plumbing system.

Splash Pool and Spa Antifreeze is formulated specifically for recreational water systems, offering burst protection down to -50 degrees Fahrenheit. Unlike automotive antifreeze, which is highly toxic to humans and pets, this propylene-glycol-based formula is completely non-toxic and environmentally safe. It lubricates pool gaskets and seals during the dry winter months, preventing dry rot and extending their operational life.

• Temperature Rating: Burst protection down to -50°F (-45°C)
• Chemical Base: Propylene glycol (non-toxic, eco-friendly)
• Usage Rate: Typically 1 gallon per 10–15 feet of 1.5-inch pipe
• Safe Surfaces: Compatible with PVC, copper, and flexible plastic piping

Never pour this antifreeze directly into the pool water or use automotive ethylene-glycol antifreeze, which will ruin pool chemistry and poison swimmers. It must be poured directly into the cleared plumbing lines before plugging them shut. This is an absolute necessity for pool owners in northern states with deep frost lines, but unnecessary for southern climates where ground freezes are rare.

Pool Water Bag – Robelle Heavy-Duty Double Tube

For pools utilizing traditional solid winter covers rather than tensioned safety covers, water bags are the only reliable way to keep the cover in place. Without weight along the perimeter, winter winds will easily get underneath the tarp, flapping it around and pulling it into the pool. Properly weighted bags keep the cover flush against the pool deck, preventing wind lofting and debris intrusion.

The Robelle Heavy-Duty Double Tube water bags are built from thick, 18-gauge vinyl that resists punctures and UV degradation over long winters. The double-tube design prevents the bags from rolling away on sloped pool decks, which is a common failure point for single-tube designs. They feature leak-proof valves that are easy to fill with a standard garden hose and seal tightly against winter expansion.

• Material Thickness: Heavy-duty 18-gauge virgin vinyl
• Length Options: Available in 8-foot and 10-foot lengths
• Design: Double-chamber construction prevents rolling
• Valves: Leak-resistant, easy-open cap system

Only fill these water bags halfway to three-quarters full to allow room for the water to expand when it freezes into solid ice. Filling them completely will cause the vinyl seams to split under ice expansion, rendering them useless by mid-winter. They are the ideal, cost-effective anchoring solution for standard solid cover setups, but completely unnecessary if you have a modern anchor-secured safety cover.

Safety Cover Anchor – Poolzilla Universal Brass Anchor

Tensioned safety covers rely on heavy-duty brass anchors embedded directly into the concrete deck to hold the cover taut against snow loads and wind. Over several seasons, cheap or original anchors can strip, corrode, or get jammed with dirt and salt, making them impossible to raise or lower. Upgrading to high-quality brass replacements ensures your safety cover remains securely anchored when the winter winds blow.

The Poolzilla Universal Brass Anchor is machined from premium, corrosion-resistant solid brass, designed to withstand harsh winter chemicals and road salt. Its universal dimensions mean it fits seamlessly into standard 3/4-inch drilled holes, making them perfect replacements for damaged factory anchors. The clean thread design allows them to screw up easily in the fall and sit completely flush with the deck in the summer.

• Material: Corrosion-resistant solid brass construction
• Dimensions: Fits standard 1-5/16 inch anchor wells with 3/4 inch thread size
• Design: Hex-head top for easy adjustment with standard tools
• Pack Sizes: Available in single, 10, 20, and 50-pack configurations

Before installing, blow any accumulated dirt, sand, or debris out of the existing deck holes to prevent cross-threading the new brass inserts. Applying a dab of silicone-based lubricant to the threads in the fall will prevent them from seizing during the damp winter months. These are essential for anyone replacing worn-out anchors on an existing safety cover system, but not needed for wood or paver decks without special collar adapters.

How to Clear and 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 trapped. Start by lowering the pool water level below the skimmer mouth and return jets to prevent water from splashing back into the lines. Connect your pool line blower directly to the pump’s strainer basket or the skimmer port using a secure, airtight adapter.

Work systemically through your valves, closing off all lines except the one you are actively blowing out to maximize air pressure. You will know a line is clear when you see a steady stream of air bubbles and mist bursting from the pool fittings. Once clear, quickly insert your expansion plugs or Gizzmo into the fittings while the air pressure is still maintaining the dry pocket, ensuring a perfect seal.

Do not forget the main drain line at the bottom of the pool, which cannot be easily plugged from the surface. Blow air through the main drain line until you see massive air bubbles boiling up from the bottom of the deep end, then quickly close the valve at the pad to create an “air lock” that keeps water from rising back up the pipe. This simple, air-trapping technique protects the deep drain line without requiring you to dive to the bottom of the pool.

Crucial Maintenance Steps for the Off-Season Months

Winterizing your pool is not a “set-it-and-forget-it” task; active off-season monitoring prevents unexpected spring surprises. Periodically check your pool cover to ensure it remains taut and free of heavy debris buildup, which can stress the anchors and springs. Clear heavy accumulation of leaves and twigs, as decomposing organic matter can stain vinyl and plaster if it slips past the cover edges.

Monitor the water level beneath the cover during periods of heavy winter rain or snowmelt. If the water rises too high and touches the underside of a mesh safety cover, it will draw dirty water and organic debris up onto the surface, creating a messy paste. Keep a cover pump ready to draw down excess water, maintaining a safe gap of at least 12 to 18 inches below the deck level.

Finally, perform a quick visual inspection of your equipment pad and winter plugs after major freeze-thaw cycles. Sudden temperature shifts can cause plastics to contract and shift, occasionally loosening expansion plugs or causing cover springs to slip. Catching these minor shifts in January saves you from a major headache when you pull the cover off in May.

Taking the time to properly winterize your inground pool with the right gear pays massive dividends when the spring thaw arrives. By systematically clearing your lines, securing your cover, and balancing your off-season chemistry, you protect your backyard investment from freeze damage and algae. When the warm weather returns, you will be rewarded with a crystal-clear pool that is ready for another season of fun.