How to Close Your Above Ground Pool for Winter

Understanding When and Why to Close Your Above Ground Pool

Closing an above ground pool for winter is an important maintenance task that protects your pool equipment and structure from cold weather damage. Most pool owners in northern climates should close their pools when water temperatures consistently drop below 65 degrees Fahrenheit, which typically occurs in late September through November depending on your location. Water that freezes can expand and damage pool walls, pumps, filters, and plumbing lines if proper winterization steps are not taken.

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The timing of pool closure varies significantly by region. In areas where temperatures remain mild year-round, such as southern Florida or parts of California, many pool owners keep their pools open throughout winter with minimal maintenance. However, in states like Michigan, Minnesota, New York, and Pennsylvania, where temperatures regularly drop below freezing, closing the pool becomes necessary. Even a single hard freeze can cause thousands of dollars in damage to pool equipment if the pool has not been properly prepared.

Understanding your specific climate helps you plan ahead. If you live in a region with harsh winters, you might begin your closing process in early autumn rather than waiting until the last moment. This gives you time to gather supplies, schedule any professional services if needed, and work through the process methodically. Pool owners who rush their closing procedures often miss important steps that prevent freeze damage.

The basic reason for winterization is straightforward: water expands when it freezes. This expansion can crack pool walls, rupture vinyl liners, and damage metal components. Additionally, algae and bacteria can grow in stagnant water during winter months, making reopening more difficult in spring. Proper chemical treatment during closure prevents these problems and reduces the work needed when you reopen your pool.

Practical Takeaway: Start planning your pool closure about four to six weeks before you expect the first hard freeze in your area. Check your local weather patterns from previous years to determine the typical freezing date, and mark your calendar to begin gathering supplies and preparing your equipment in advance.

Gathering Necessary Supplies and Equipment

Before beginning the actual closing process, you need to gather several categories of supplies: chemicals, equipment, and materials. The chemical supplies include pool shock treatment, algaecide, winterizing chemical kits, and potentially pH adjusters. Most pool supply stores sell winterization kits specifically designed for above ground pools that contain pre-measured amounts of the chemicals you'll need. These kits cost between $40 and $100 depending on your pool size and quality.

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Equipment you may need includes a pool skimmer net, pool brush, garden hose, submersible pump or siphon (if draining water), and potentially a wet/dry vacuum. You'll also need basic tools such as wrenches to disconnect pump and filter connections. If your pool has a deck or surrounding area with concrete, you might need a pressure washer or stiff brush to clean it before winter. Most pool owners already have these basic tools at home, but it's worth checking your supply before you begin.

Specific supplies for covering and protecting your pool include a winter cover (the type depends on your pool size), cover pumps if you plan to leave water on top of the cover, and potentially antifreeze for above ground pool lines. The winter cover itself represents a significant investment, ranging from $100 for basic tarps to $500 or more for reinforced, anchored covers designed for heavy snow loads. The cover type you choose affects how much maintenance you'll need to perform during winter months.

Water testing supplies are also essential. You can purchase an inexpensive test strip kit for $15 to $30, or use a more detailed liquid test kit for $40 to $60. These tools help you verify that water chemistry is properly balanced before you close the pool. Many pool supply stores offer water testing services, sometimes for free or for a small fee, if you prefer not to purchase testing equipment.

Consider where you'll store equipment you remove from the pool. Pump motors, filters, and other components should be stored in a dry location such as a basement, garage, or garden shed. Storing these items outside or leaving them exposed to weather can reduce their lifespan significantly. If you don't have adequate storage space, you might choose to leave some equipment in place rather than removing it, which affects which closing method you select.

Practical Takeaway: Create a detailed checklist of supplies you need based on your pool size and your area's climate. Visit your local pool supply store to see what winterization kits are available and ask staff which products they recommend for your specific pool type. This visit also allows you to confirm prices and availability before you begin your closing work.

Balancing Water Chemistry and Treating Your Pool

Proper chemical balance is the foundation of successful pool winterization. Before you add winterizing chemicals, you need to balance the basic water chemistry: pH, alkalinity, and calcium hardness. This prevents damage to your pool structure and equipment during the winter months. Water with improper pH can corrode metal parts or damage vinyl liners, while water that is too acidic or alkaline can become cloudy or encourage algae growth even in cold temperatures.

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Start by testing your water using either test strips or a liquid test kit. You're looking for pH between 7.2 and 7.6, alkalinity between 80 and 120 parts per million (ppm), and calcium hardness between 200 and 400 ppm. If your pH is too high, add pH decreaser (sodium bisulfate). If it's too low, add pH increaser (soda ash). Alkalinity adjustments help stabilize pH, so adjust alkalinity first if it needs correction. Follow the product instructions for exact dosing based on your pool volume.

After basic chemistry is balanced, shock your pool. Pool shock treatment is a powerful oxidizer that removes organic contaminants, bacteria, and algae that could cause problems during winter storage. Use the amount specified on the shock product for your pool size, and run your pump and filter for at least 24 hours after adding shock. This circulation allows the shock to distribute throughout the pool and work effectively. Some pool owners prefer to shock their pools a few days before final closing to verify the water is crystal clear before covering.

Add algaecide after shock treatment has had time to work, typically at least 12 hours after shocking. Algaecide prevents algae growth during the cold months when your circulation system isn't running continuously. Choose an algaecide appropriate for winter use—some products are specifically formulated for closed pools. Winter algaecides are often less harsh than summer products since you won't be swimming in the water during this period.

Finally, add your winterizing chemical kit according to package directions. These kits contain a combination of chemicals designed to keep water balanced and protected throughout winter without active circulation. They typically include biocide to prevent bacterial growth, clarifier to keep water clear, and additional alkalinity adjusters. The kit instructions specify how many kits you need based on your pool's gallon capacity, so calculate this carefully before adding chemicals.

Practical Takeaway: Test your water chemistry three to five days before you plan to close your pool, then retest the day before closing. This timing allows you to make adjustments and have them circulate through your system before winterization. Keep records of your water test results and chemical additions; this information helps when you reopen your pool in spring.

Draining Your Pool or Preparing It to Remain Full

One of the most important decisions in closing your above ground pool is whether to drain it completely or leave water in it. This decision depends on several factors including your pool type, local climate severity, and your maintenance preferences. Above ground pools with vinyl liners typically should NOT be completely drained, as an empty liner can become brittle and crack during winter. Instead, drain the pool to about 18 to 24 inches below the skimmer opening, or if you don't have a skimmer, drain to about 12 to 18 inches from the top of the pool wall.

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Draining should be done slowly and carefully. Never drain directly into your neighbor's yard or into storm drains without checking local regulations. Many communities have specific rules about where pool water can be discharged. If you have a sump pump or can route water to a garden area, that's often acceptable. Some pool owners use a submersible pump connected to a garden hose to direct water where it's needed. The draining process typically takes several hours for an average above ground pool.

If you're completely draining your pool for maintenance or if your pool type requires full draining, ensure the ground underneath your pool has adequate drainage. Standing