6 Steps: How to Winterize Inground vs Above Ground Pools That Prevent Costly Damage

When winter approaches, properly closing your swimming pool becomes crucial to protect your investment and simplify next season’s opening. Whether you’re a first-time pool owner or a seasoned veteran, knowing the specific steps for winterizing your particular type of pool can save you thousands in potential repairs and maintenance costs.

In this guide, you’ll discover the essential six-step process for winterizing both inground and above-ground pools, highlighting the key differences between these two pool types. We’ll walk you through everything from balancing water chemistry to installing the right winter cover, ensuring your pool remains protected during the cold months ahead.

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Step 1: Balance Pool Water Chemistry Before Winter

Properly balancing your pool’s water chemistry is the crucial first step in winterizing both inground and above-ground pools. This prevents corrosion, staining, and algae growth during the winter months.

Testing and Adjusting pH Levels for Both Pool Types

Test your pool water using a reliable test kit to measure pH levels between 7.2 and 7.6. For inground pools, pay special attention to calcium hardness (200-400 ppm), while above-ground pools typically need slightly lower levels (175-225 ppm). Adjust with pH increaser or decreaser as needed, allowing the chemicals to circulate for 4-6 hours before retesting.

Adding Winter Chemicals to Prevent Algae Growth

Add a winter algaecide specifically formulated for your pool type to prevent algae blooms during dormant months. Inground pools generally require 1 quart per 15,000 gallons, while above-ground pools need about 1 pint per 10,000 gallons. Distribute chlorine shock throughout the pool and run the filtration system for at least 12 hours to ensure proper chemical distribution before closing.

Step 2: Clean the Pool Thoroughly

Thorough cleaning is essential before winterizing your pool to prevent algae growth and staining during the off-season. Different pool types require specific cleaning approaches to ensure proper winterization.

Vacuuming and Skimming Debris for Inground Pools

For inground pools, use a pool vacuum to remove all debris from the bottom of the pool. Skim the surface thoroughly with a net to catch floating leaves and insects. Pay special attention to corners and steps where debris tends to accumulate. Running your filtration system for 4-6 hours after vacuuming helps clear remaining microscopic particles.

Scrubbing Walls and Floor for Above Ground Pools

Scrub the walls and floor of your above ground pool using a soft-bristle brush to remove algae and biofilm. Focus on waterline areas where oils and sunscreen residue collect. Use gentle, circular motions to avoid damaging the liner. For stubborn stains, apply a non-abrasive pool cleaner specifically formulated for vinyl or metal surfaces.

Step 3: Lower the Water Level

Proper Drainage Depth for Inground Pools

For inground pools, you’ll need to drain water to about 4-6 inches below the skimmer opening. This prevents water from entering the skimmer during freeze-thaw cycles, which could damage the plumbing. Use a submersible pump for concrete pools, but be more cautious with vinyl and fiberglass pools to prevent liner damage or floating.

Water Level Guidelines for Above Ground Pools

Above ground pools require less draining—typically only 12-18 inches below the skimmer. You shouldn’t drain these pools completely as the liner can shrink, crack, or shift without water weight. A simple garden hose siphon works effectively for this task, and remember to remove all drain plugs from your filtration system.

Step 4: Winterize the Plumbing System

Blowing Out Lines and Adding Antifreeze for Inground Systems

Properly winterizing your inground pool’s plumbing prevents costly freeze damage. Use an air compressor or shop vac to blow air through each plumbing line until bubbles appear in the pool. After blowing out all lines, pour pool-grade antifreeze into the skimmer and other plumbing access points. This double protection ensures no water remains to expand and crack pipes during freezing temperatures.

Disconnecting Pumps and Filters for Above Ground Pools

For above ground pools, disconnect all hoses from the pump, filter, and skimmer basket. Remove drain plugs from the pump and filter, allowing them to drain completely. Store these components in a dry, temperature-controlled space like a garage or basement. Don’t forget to remove and clean the skimmer basket and any attached equipment before storage to prevent damage from moisture and freezing.

Step 5: Install Winter Cover Protection

Securing Safety Covers for Inground Pools

Properly installing a safety cover is critical for inground pool protection. Secure mesh safety covers with spring-loaded anchors that lock into brass fittings on your pool deck. Ensure the cover is taut across the entire surface with no sagging areas where water or debris can collect. For solid covers, use water bags placed end-to-end around the perimeter to prevent wind from getting underneath.

Attaching Winter Covers for Above Ground Pools

Above ground pools require a winter cover that extends 3-4 inches beyond the pool walls. Secure the cover with the included cable and winch system, threading it through the cover’s grommets and tightening until snug but not overstretched. Place air pillows in the center of the pool before covering to absorb ice expansion pressure and prevent cover damage from winter precipitation.

Step 6: Maintain Throughout Winter Months

Winterizing your pool isn’t a “set it and forget it” task. Regular maintenance during winter months ensures your pool remains protected until spring. Check your cover weekly to remove debris and standing water that could damage it over time. For inground pools monitor water chemistry monthly adjusting as needed to prevent scale buildup.

Above-ground pool owners should inspect the walls periodically for signs of stress and ensure the cover remains securely fastened. After snowstorms or freezing rain carefully remove excessive weight from your cover to prevent sagging or tearing.

By following these six winterization steps you’ll save time money and headaches when swimming season returns. Your properly winterized pool—whether inground or above-ground—will be ready for a smooth reopening when warmer weather arrives.

Frequently Asked Questions

Why is winterizing a swimming pool important?

Winterizing your pool protects it from freeze damage and prevents algae growth during the off-season. Proper winterization not only extends the life of your pool components but also makes reopening easier in spring. Without this crucial maintenance, you risk costly repairs to damaged pipes, equipment, and surfaces that can occur during freezing temperatures.

When should I start winterizing my pool?

Start winterizing when water temperatures consistently drop below 65°F (typically in fall). This timing is crucial because algae and bacteria are less active in cooler water, making chemical treatments more effective. Plan to complete the process before the first freeze in your area to prevent damage to your pool’s plumbing and equipment.

What chemicals do I need for pool winterization?

You’ll need a water testing kit, pH increaser/decreaser, calcium hardness increaser, algaecide specifically labeled for winter use, and chlorine shock. Balancing your water chemistry with these products prevents corrosion, staining, and algae growth during the winter months. Always follow manufacturer recommendations for your specific pool type and size.

How do I winterize the plumbing in an inground pool?

Blow out plumbing lines using an air compressor or shop vac until bubbles appear in the pool. Install winterizing plugs in return jets and skimmers. Add pool-grade antifreeze to prevent freeze damage in pipes that cannot be completely drained. This process is critical to prevent cracked pipes and expensive repairs come springtime.

What’s the difference between winterizing inground vs. above-ground pools?

Inground pools require more extensive plumbing protection, deeper water level reduction (4-6 inches below skimmer), and specialized safety covers secured with anchors. Above-ground pools need less water reduction (12-18 inches), simpler equipment removal, and covers secured with cables and winches. Above-ground pools also require air pillows to protect against ice expansion.

Do I need to completely drain my pool for winter?

No! Never completely drain your pool for winter. For inground pools, lower water 4-6 inches below the skimmer opening. For above-ground pools, lower only 12-18 inches below the skimmer. Complete draining can cause vinyl liners to shrink or crack, and concrete pools may experience structural damage from groundwater pressure.

How do I properly install a winter pool cover?

For inground pools, stretch the cover tightly across the surface, securing with spring-loaded anchors or water bags for solid covers. For above-ground pools, center the cover, ensuring it extends 3-4 inches beyond pool walls, and secure with a cable and winch system. Always place air pillows in the center of above-ground pools to absorb ice expansion.

What happens if I don’t winterize my swimming pool?

Without proper winterization, you risk freeze damage to pipes and equipment, algae blooms requiring intensive treatment, staining and corrosion of pool surfaces, and structural damage from ice expansion. These issues can lead to repairs costing thousands of dollars and delay your pool opening in spring.