9 Essential Supplies for Winterizing an In-Ground Pool

As autumn leaves begin to carpet the backyard, the reality of the approaching freeze signals that it is time to put your beloved backyard oasis to bed. Cutting corners during this seasonal transition is a gamble that often ends in cracked pipes, ruined liners, and a massive repair bill come spring. Investing in the right winterization gear now ensures your in-ground pool remains protected against the harshest winter elements, saving both your sanity and your budget.

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

Why Proper Winter Pool Prep Saves You Money

Water expands by about nine percent when it freezes, exerting immense pressure on anything containing it. In an in-ground pool, this expansion can easily crack heavy-duty PVC underground pipes, split skimmer wells, and tear vinyl liners. Fixing these subterranean plumbing disasters requires excavating concrete decks, costing thousands of dollars in emergency masonry and plumbing fees.

Proper winterization halts this destructive cycle by removing water from vulnerable areas and chemically stabilizing the remaining pool water. Keeping algae at bay during the off-season prevents permanent staining and saves hours of scrubbing and chemical shock treatments in the spring. A small investment in seasonal supplies now pays massive dividends by extending the lifespan of your pool’s infrastructure.

Safety Pool Cover – Loop Loc Mesh Safety Cover

A safety cover acts as a structural barrier over your pool, protecting the water from debris while ensuring pets and children cannot fall into the pool. Traditional tarps can collect heavy standing water, creating a drowning hazard and straining the pool walls. A high-quality safety cover distributes weight evenly and keeps the pool secure through heavy snowfalls and winter windstorms.

The Loop Loc Mesh Safety Cover is the industry benchmark for structural integrity and debris filtration. Made from incredibly strong, lightweight mesh, it allows rain and melting snow to drain through while blocking leaves, twigs, and fine dirt. This eliminates the need for a cover pump and prevents water from pooling on top.

• Material: High-grade polypropylene mesh fabric
• Break Strength: Exceeds ASTM safety standards (supports up to 1,000 lbs)
• Anchoring: Flush-mount brass anchors for concrete decks
• Warranty: 15-year pro-rated manufacturer warranty

Installation requires drilling brass anchors into your concrete deck, which demands precision and a rotary hammer drill. Because mesh allows fine silt and melted snow to pass through, you may notice some fine dust on the pool floor during spring opening. However, the trade-off is a cover that never requires pumping or heavy lifting.

This cover is the ultimate choice for homeowners with children or pets who prioritize safety and low off-season maintenance. It is not ideal for pool owners who want a completely dry pool interior or those without a solid concrete deck to anchor the brass pins.

Pool Winterizing Kit – In The Swim Ultimate Kit

A winterizing kit provides a pre-measured chemical defense system to keep your pool water stable, clean, and clear during the cold months. Without these chemicals, standing water becomes a breeding ground for algae and bacteria as soon as temperatures rise in early spring. These kits prevent staining, scale buildup, and algae blooms from taking hold under your cover.

The In The Swim Ultimate Kit is a highly effective, copper-free chemical regimen designed to protect your pool surfaces through the winter. It features a powerful combination of slow-dissolving sanitizers, stain preventers, and cold-weather algaecide. The inclusion of a time-release winter floater ensures consistent chemical distribution even when the filtration system is completely shut down.

• Pool Capacity: Kits available for pools up to 10,000, 20,000, and 35,000 gallons
• Included Chemicals: Chlorine-free pool shock, winterizer algaecide, stain away, and a slow-release winter floater
• Compatibility: Safe for vinyl, plaster, and fiberglass pools

For the best results, you must balance your pool chemistry—especially pH and alkalinity—before adding this kit. Vacuum the pool thoroughly to remove organic debris, which can consume the winterizing chemicals prematurely. Add the liquid chemicals directly to the pool water with the filter running for at least four hours to ensure thorough mixing before shutting down the pump.

This kit is perfect for pool owners looking for a convenient, all-in-one chemical solution to avoid green water in the spring. It is not necessary for those who prefer to source and mix their chemicals individually or those who keep their pools open year-round.

Pool Air Pillow – Robelle Ice Equalizer Cushion

An air pillow sits in the middle of your pool under a solid winter cover to relieve lateral pressure caused by freezing water. When ice forms on the pool surface, it expands outward, pushing against the pool walls and potentially cracking the tile or shifting the coping. The air pillow compresses under this pressure, absorbing the force and directing the expansion upward instead of outward.

The Robelle Ice Equalizer Cushion is built to handle the intense compression of shifting ice sheets without popping. Constructed from heavy-gauge vinyl, this pillow resists punctures and remains flexible in sub-zero temperatures. It features reinforced grommets on the corners, allowing you to secure it easily in the dead center of the pool.

• Size Options: 4′ x 4′, 4′ x 8′, and 4′ x 15′ options
• Material: 16-gauge vinyl construction
• Valves: Push-in leak-proof valves for easy inflation

The most common mistake when using an air pillow is inflating it completely. Only inflate the pillow to 60% to 70% of its total capacity to allow room for compression when ice expands around it. You must also use durable nylon ropes tied to opposite sides of the pool deck to keep the pillow centered, preventing it from drifting to one corner.

This product is highly recommended for pool owners in freezing climates who use solid winter covers. It is not necessary if you use a high-tension mesh safety cover that does not touch the pool water surface.

Pool Cover Pump – Little Giant APCP-1700 Pump

Solid pool covers inevitably accumulate rainwater, melting ice, and heavy snow over the winter. This standing water creates a breeding ground for mosquitoes, collects rotting leaves, and adds thousands of pounds of stress to your pool walls and cover. A dedicated cover pump automatically removes this water before it can damage your pool structure or pull your cover into the deep end.

The Little Giant APCP-1700 is a fully submersible pump designed specifically for the rigors of winter pool cover maintenance. It features a mechanical float switch that activates the pump automatically when water levels rise, draining the cover without requiring manual supervision. The wide plate base provides excellent stability, preventing the pump from tipping over on soft vinyl covers.

• Flow Rate: Up to 1,700 gallons per hour (GPH)
• Activation: Turns on automatically in 2 inches of water; shuts off in 1.5 inches
• Power Cord: 25-foot heavy-duty power cord
• Discharge Connection: Standard 3/4-inch garden hose thread

To maximize the pump’s lifespan, you must regularly clear leaves and twigs from the intake screen to prevent clogging. Always unplug the pump when deep-freeze temperatures are expected, as water freezing inside the pump housing can crack the internal impeller. Use a heavy-duty, outdoor-rated extension cord if your electrical outlet is far from the pool.

This pump is essential for anyone using a solid winter cover or tarp that collects standing water. It is not required for pool owners who utilize mesh safety covers, as those covers allow water to drain naturally into the pool.

Skimmer Guard – Gizzmo Ultra Expansion Plug

The pool skimmer is one of the most vulnerable components during a winter freeze because it sits right at the water level. Water trapped inside the plastic skimmer well will expand as it turns to ice, easily cracking the housing and causing a major underground leak. A skimmer guard absorbs this freeze expansion while simultaneously sealing the plumbing line below.

The Gizzmo Ultra Expansion Plug is a heavy-duty, blow-molded plastic tube designed to collapse under pressure, absorbing the expansion of freezing water. This protects the skimmer walls from cracking while the threaded bottom creates a watertight seal in your skimmer line. It is a simple, highly effective insurance policy for your pool’s filtration system.

• Thread Size: 1.5-inch and 2-inch tapered threads to fit most standard skimmers
• Length: 16 inches for deep skimmer wells
• Material: High-density, blow-molded plastic

Before screwing the Gizzmo into place, wrap the threads with Teflon tape to ensure a completely airtight and watertight seal. Do not overtighten the unit into the skimmer bottom; hand-tightening is sufficient to prevent leaks without stripping the plastic threads. For extra safety, place an empty plastic bottle inside the skimmer well alongside the Gizzmo to absorb any additional ice pressure.

This guard is a must-have for in-ground pools in freeze-prone climates with standard threaded skimmers. It is not suitable for older, non-threaded skimmer wells unless you purchase a specialty rubber expansion adapter.

Winter Expansion Plug – Swimline Rubber Plug

Once you blow the water out of your pool’s return lines, you must seal them to prevent water from creeping back in. If water re-enters the lines and freezes, the pipes will split, leading to costly excavation repairs in the spring. Heavy-duty rubber expansion plugs seal these openings, keeping your plumbing dry and protected all winter long.

The Swimline Rubber Plug is built with premium chemical-resistant rubber and marine-grade stainless steel hardware. When you tighten the wingnut, the rubber expands inside the pipe, creating a reliable, airtight seal that resists pressure and freezing temperatures. The ribbed outer design provides extra gripping power against smooth PVC pipe walls.

• Size Range: Available in sizes #00 (1/2″) up to #14 (2.5″)
• Hardware: Corrosion-resistant nylon wingnuts and stainless steel bolts
• Material: Heavy-duty ribbed rubber

Measuring your return lines precisely is crucial before purchasing, as even a fraction of an inch can prevent a proper seal. When installing, tighten the wingnut until the rubber bulges perceptibly against the inside of the pipe to confirm a snug fit. Regularly inspect the rubber for cracks or dry rot before each winter use, replacing any plugs that show signs of degradation.

These plugs are essential for any pool owner DIY-ing their winter closing to secure returns, cleaner lines, and skimmer ports. They are not suitable for threaded fittings that require specialized threaded male plugs.

Pool Line Blower – Cyclone Pro Bypass Blower

Blowing out the plumbing lines is the most critical step in protecting your underground pipes from freeze damage. Standard shop vacuums do not have the static pressure required to push water out of deep lines, especially the main drain at the bottom of the pool. A dedicated pool line blower delivers the high-volume, low-pressure air needed to purge all water from your filtration lines.

The Cyclone Pro Bypass Blower is a professional-grade tool designed specifically for clearing pool lines. It features a powerful two-stage motor that produces incredible bypass air pressure, allowing it to clear multiple lines simultaneously without burning out. The durable housing is built to withstand rugged backyard use and transit.

• Motor: 3.0 horsepower, 2-stage bypass motor
• Airflow: 130 CFM (Cubic Feet per Minute) at open flow
• Hose: 2-inch flexible hose with quick-connect fittings

This blower operates at extremely high noise levels, so hearing protection is highly recommended during use. Connect the blower hose to your pump basket intake or skimmer line using the appropriate quick-connect fittings to ensure a sealed system. Take your time clearing each line individually to ensure no pocket of water remains trapped in low-lying plumbing loops.

This tool is ideal for dedicated DIY pool owners who want to bypass professional closing services year after year. It is not necessary for pool owners who prefer to hire a professional pool service or those living in completely frost-free climates.

Pool Antifreeze – Splash Pool and Spa Antifreeze

Even after blowing out your plumbing lines, a small amount of residual water can remain in low-lying sections of your pipes. If this water freezes, it can still cause localized cracks and leaks in your PVC lines. Adding specialized pool antifreeze to your lines provides a critical safety net, preventing any leftover water from expanding.

Splash Pool and Spa Antifreeze is formulated with premium propylene glycol, making it completely non-toxic and safe for pool plumbing, vinyl liners, and swimmers. It prevents burst pipes in temperatures down to -50°F (-46°C), providing ultimate winter peace of mind. Unlike automotive antifreeze, this formula is safe to discharge back into the pool during spring startup.

• Base Chemical: 100% non-toxic propylene glycol (never use automotive ethylene glycol)
• Temperature Rating: Burst protection down to -50°F (-46°C)
• Volume: Standard 1-gallon bottles

Never pour pool antifreeze directly into your main pool water; it is strictly intended for plumbing line application. Use a funnel to pour the antifreeze down your skimmer lines and return jets after you have blown them out and sealed them with expansion plugs. This creates a protective barrier in the deepest, most vulnerable parts of your plumbing system.

This product is highly recommended for pool owners in deep-freeze states where winter temperatures drop below zero for extended periods. It is unnecessary for pool owners in mild, temperate climates where the ground does not freeze.

Winter Cover Seal – Buffalo Blizzard Cover Wrap

Wind is a major enemy of pool covers during the winter months. Strong gusts can catch the edges of a solid cover, lifting it up, tearing the material, and blowing dirt and debris directly into your clean pool water. A winter cover seal acts like heavy-duty plastic wrap, sealing the perimeter of your pool cover to keep wind out and lock the cover securely in place.

The Buffalo Blizzard Cover Wrap is a high-tensile strength stretch film designed to withstand freezing temperatures and strong winds. It stretches tightly around the perimeter of your pool, clinging to itself without leaving any sticky adhesive residue on your pool walls or coping. The built-in UV inhibitors prevent the film from breaking down under direct winter sunlight.

• Dimensions: 80-gauge thickness, 500 feet per roll
• Width: 20-inch wide band for maximum coverage
• UV Protection: Built-in inhibitors prevent sun degradation

For the most secure hold, wrap the perimeter of your pool at least three to four times, overlapping each layer by half the width of the band. Ensure you wrap tightly against the coping edge to create an airtight seal that prevents wind from slipping underneath. When spring arrives, simply cut the wrap away with a utility knife and discard it.

This wrap is incredibly useful for pool owners with exposed, raised-coping in-ground pools or above-ground pools in high-wind regions. It is not designed for flush-mounted safety covers that are secured by brass deck pins.

How to Safely Blow Out Your Pool Plumbing Lines

Clearing your underground plumbing lines is a precise operation that must be done in a specific sequence to prevent water from rushing back in. Start by lowering your pool’s water level to about four to six inches below the skimmer mouth, which prevents water from splashing back into the lines during the blowout. Next, connect your high-volume line blower to the main suction line inside the pump basket or a dedicated skimmer port.

Turn on the blower and open the valve for your shallowest return line first, keeping all other valves closed to maximize air pressure. You will hear a loud bubbling sound followed by a violent mist of water and air spraying out of the return jet. Once the line is blowing pure air with no water, quickly insert your winter expansion plug into the jet and tighten the wingnut to seal the line.

[Pool Blower] ──> [Pump Basket Intake] ──> [Individual Line Valve] ──> [Return Jet (Plug Immediately)] 

Repeat this process for each return line, moving from the shallow end to the deep end of the pool. To clear the main drain at the bottom of the pool, blow air through the line until you see a massive eruption of bubbles in the deep end. While the air is still blowing violently, quickly close the slide or ball valve at the equipment pad to trap the air pocket inside the pipe—this is known as air-locking the line, which naturally prevents water from rising back up the pipe without needing a physical plug.

Storing Your Summer Pool Equipment the Right Way

Leaving expensive pump motors, salt cells, and chlorinators exposed to freezing rain and snow is a recipe for premature equipment failure. Disconnect your pump and filter system entirely, opening all drain plugs at the bottom of the pump basket and filter tank to drain remaining water. Store pump motors, salt chlorine generators, and pressure cleaners indoors in a climate-controlled garage or basement to prevent internal components from cracking.

Clean your filtration media thoroughly before winter storage. Cartridge filters should be chemically washed and dried, while sand or D.E. filters need a deep backwash to prevent mold and mineral scaling from hardening over the winter. Keep all loose drain plugs, O-rings, and pressure gauges together in the empty pump basket so they do not go missing during the off-season.

Finally, safely store all summer pool chemicals in a cool, dry place away from direct sunlight and moisture. Liquid chlorine and acid should never be stored near metal pool equipment, as the fumes can cause severe corrosion. Organize your pool toys, ladders, and skimmer baskets in a dedicated deck box or shed to shield them from destructive winter UV rays.

Safe Harbor Until Spring

Taking the time to winterize your in-ground pool with the proper supplies is the ultimate act of preventative maintenance. By executing these steps methodically, you protect your backyard investment and ensure a stress-free reopening when warm weather returns. Equip yourself with the right gear this autumn, and rest easy knowing your pool is safe until spring.