Whether you own an in-ground or above-ground pool, closing your pool properly at the end of the swimming season is essential for maintaining its condition and ensuring smooth reopening in the spring. Proper pool closure prevents damage from freezing temperatures, protects your investment, and saves you time and money in the long run.
This in-depth guide will walk you through everything you need to know about closing a pool, including the necessary preparations, equipment handling, chemical balancing, and winterizing steps. By following these best practices, you’ll be able to preserve your pool’s longevity and functionality.
Why Closing a Pool Matters
Closing a pool is more than just covering it up for the season. It’s a critical maintenance process that helps prevent algae growth, freezing damage, and chemical imbalances. Here’s why it’s important:
- Prevents freezing damage: Water expands when it freezes, which can crack your pool’s plumbing and equipment.
- Protects the pool structure: Proper closure protects the tile, liner, or concrete surfaces from staining and deterioration.
- Maintains water quality: Balanced chemicals during closure inhibit algae and bacteria growth during dormancy.
- Reduces spring cleaning: A well-closed pool means less work when it’s time to open it again.
Seasonal pool owners—especially those in colder climates—should never skip this step, no matter how short the off-season might be.
When to Close Your Pool
The best time to close a pool depends on your region and the length of your swimming season. Generally, pool closures should occur when nighttime temperatures remain consistently below 65°F (18°C) and pool usage decreases. A good benchmark is when the average water temperature drops below 65°F, which is typically in the fall, just before the first frost.
Timing matters: closing too early can lead to unnecessary chemical use, while closing too late can expose your equipment to freezing temperatures before proper protection is in place.
Closing an In-Ground vs. Above-Ground Pool
While the main principles of pool closing remain similar, there are slight differences between closing an in-ground pool and an above-ground pool due to structural variations.
- In-Ground Pools: More complex due to permanent structures and plumbing systems. Winterizing involves draining water below skimmer and return jet levels, removing equipment, and applying covers capable of bearing snow and ice weight.
- Above-Ground Pools: Easier to winterize. Water levels are lowered only slightly below the skimmer. Covers and air pillows are used, and some pool owners may opt to drain the pool entirely, especially in very cold climates.
Regardless of the type, the goal is to protect the structure and equipment from freezing, corrosion, and staining.
Preparing for Pool Closure: Step-by-Step
Before diving into the technical work, ensure you have all the necessary tools, chemicals, and equipment on hand. The following steps should be completed before you start draining water or disconnecting systems.
1. Clean the Pool Thoroughly
Before you start lowering the water level:
- Brush all walls and the pool floor.
- Vacuum the pool to remove all debris.
- Skim the surface to eliminate floating leaves and insects.
Clearing out debris prevents staining and simplifies spring cleanup.
2. Remove Accessories and Equipment
- Remove ladders, diving boards, skimmer baskets, and return jets.
- Disconnect and store cleaning equipment like automatic pool cleaners, vacuums, and robotic units.
Make sure all components are clean and dry before storing to avoid mold and mildew.
3. Test and Balance the Water Chemistry
Proper chemical balance is crucial before closing. Use a comprehensive test kit or strips to analyze the following levels:
| Parameter | Ideal Closing Levels |
|---|---|
| pH | 7.2–7.6 |
| Alkalinity | 80–120 ppm |
| Calcium Hardness | 180–220 ppm (vinyl), 200–250 ppm (concrete) |
| Chlorine | 1–3 ppm |
Adjust chemical levels as needed before proceeding. Imbalanced water can cause staining, scaling, or etching during the winter.
Step-by-Step Pool Closing Process
Once your water is clean and balanced, you can begin the actual closure process. This requires attention to detail and proper sequencing.
1. Lower the Water Level
- In in-ground pools: Drain the water level to about 6 inches below the skimmer and return jets to prevent pipe bursts.
- In above-ground pools: Lower water just below the skimmer level or as per manufacturer recommendations.
Use a submersible pump or the pool’s built-in drain setup, ensuring you comply with local water usage regulations when draining.
2. Winterize the Pool Plumbing System
To protect your plumbing from freezing:
- Bleed the pump: Remove the filter and air lock to prevent standing water buildup.
- Blow out the lines: Use an air compressor to push water out of the plumbing lines, starting with the main drain and skimmer lines.
- Add non-toxic antifreeze: Pour swimming pool antifreeze into each line to ensure complete protection against freezing.
Ensure all water is removed from valves, filters, and heaters before storage.
3. Winterize the Filter, Pump, and Heater
Each piece of pool equipment deserves special attention during closure.
Pool Filter
- Drain all water from the filter tank.
- Clean or replace the filter media—cartridges should be cleaned, and sand or DE should be inspected and replaced if necessary.
- Store in a dry area if applicable.
Pool Pump
- Remove the pump lid and drain all internal water.
- Apply pool-safe antifreeze if recommended.
- Store indoors if possible, or use a pump cover if left outside.
Heater
- Drain all water and remove drain plugs.
- Flush with pool antifreeze if required.
- Wrap with a vented cover to prevent rust.
4. Apply Closing Chemicals and Stain Protection
After balancing the pH and alkalinity, apply the following chemicals:
- Winterizing algaecide: Prevents algae growth over the long winter period.
- Metal sequestrant: Binds dissolved metals such as copper and iron to prevent staining.
- Winterizing shock: Gives a final cleaning boost before closing.
Distribute each chemical evenly and run the pump for about 1–2 hours to circulate them thoroughly.
5. Install Winter Covers Correctly
The final step before long-term closure is covering the pool safely. The type of cover used depends on your pool structure:
Types of Pool Covers
| Type | Description | Best For |
|---|---|---|
| Winter Safety Covers | Heavy-duty covers that snap or anchor tightly around the edge, often with mesh for water drainage. | In-ground pools, especially with kids or pets around |
| Solid Winter Covers | Non-permeable, preventing debris and sunlight from entering the pool. | All pool types, especially to reduce debris and algae |
| Mesh Covers | Allow water through, reducing standing water concerns but not blocking sunlight. | Areas with heavy rain or snowfall |
How to Secure a Pool Cover
- Place the cover evenly over the pool.
- Pull taut and secure with water bags or anchor kits.
- Use an air pillow (for above-ground pools) or cover pump to manage snow and rain accumulation.
Closing Additional Pool Components
Beyond the main pool itself, certain accessories and equipment also require attention:
Pool Lights
- Remove and drain pool lights, if they are submersible.
- Store them in a dry place or according to manufacturer instructions.
Automatic Cleaners and Chlorine Floaters
- Remove all floating devices and cleaners.
- Clean and store with proper care to avoid degradation.
Solar Covers and Pool Heaters
- Solar covers should be rinsed and stored off the ground, rolled or folded, preferably inside.
- Drain and disconnect gas or heat pump systems, then protect them appropriately.
Post-Closure Maintenance
Contrary to popular belief, closing your pool doesn’t mean walking away until spring. Some ongoing care helps prevent major issues and costly repairs when the time comes to reopen.
1. Check the Cover Regularly
Even during winter, inspect the cover:
- Look for signs of stretching, tears, or sagging.
- Adjust the water level under the cover to maintain weight balance.
- Remove heavy snow buildup if the cover starts to dip into the water.
2. Monitor Water Chemistry and Level
If using a solid cover:
- Occasionally uncover one end to check water clarity and potential algae signs.
- Partially replace or treat water as needed, ensuring chemical cover-up is refreshed when necessary.
If using a mesh cover:
- Use a submersible pump or cover pump to remove excess rain or melted snow water.
3. Protect Equipment Stored Outside
- Use vented covers for filters, pumps, and heaters.
- Ensure all stored components are dry and stored in a secure location.
Closing a Saltwater Pool: Special Considerations
Saltwater pools require additional steps because their salt chlorinators can become corroded if exposed to stagnant water over winter. Here’s how closing differs:
- Thoroughly rinse the saltwater chlorinator cell with fresh water.
- Remove it and store in a dry area for winter to avoid salt bridging or corrosion.
- Balance water with a salt-specific test kit to ensure no crystal buildup occurs.
- Drain the pump basket and run antifreeze through internal lines if applicable.
Many pool professionals recommend closing saltwater pools earlier than traditional chlorine pools to avoid these delicate components sitting dormant in unbalanced water for too long.
DIY Pool Closure vs. Hiring a Professional
While closing a pool can be a DIY-friendly task, each approach comes with advantages.
When to Do It Yourself
- You have previous pool maintenance experience.
- You own standard equipment and a small to medium-sized pool.
- You have time and the right tools for water testing, antifreezing, and cover installation.
When to Hire a Pro
- You’re new to pool ownership or closing procedures.
- You have a large or complex pool system, including water features or automation.
- You prefer to ensure full compliance with manufacturer guidelines for equipment.
Professionals also often offer winter maintenance visits—ideal for peace of mind over the colder months.
Common Mistakes to Avoid When Closing a Pool
Even seasoned pool owners sometimes slip up. Avoid these common pitfalls to protect your pool effectively:
- Skipping the water chemistry balance: Leads to staining, scaling, and green water in the spring.
- Not blowing out the plumbing lines: Affects freezing and can crack underground pipes.
- Using regular antifreeze instead of pool-safe antifreeze: Damages pool surfaces and is harmful to the environment.
- Improperly sealing the cover: Allows debris, pests, and rodents to enter the pool.
- Leaving chemicals floating in water before closure: Causes discoloration when left for months.
Double-check each step with a closing checklist to avoid oversight.
Conclusion
Closing your pool properly is just as crucial as maintaining it during the swim season. Whether you choose to do it yourself or hire a professional, following these steps ensures your pool is protected from the harsh elements of winter and ready for a clean, easy opening in the spring.
From water balancing and equipment winterizing to selecting the right cover and monitoring your pool during hibernation, each action plays a role in the overall success of your pool shutdown.
By taking the time to close your pool correctly, you’ll be rewarded with clearer water, fewer repairs, and the confidence that your investment remains secure during the cold months. Plan ahead, gather the right supplies, and follow this comprehensive checklist to help your pool sleep soundly through the winter season.
By understanding what is involved in closing a pool, you can ensure a trouble-free swim season year after year.
What does it mean to close a swimming pool for the winter?
Closing a swimming pool for the winter refers to the process of preparing it for cold weather to protect its structure, equipment, and water quality during periods of non-use. This involves a series of steps including cleaning, balancing water chemistry, lowering the water level, and protecting plumbing lines and equipment from freezing. Proper winterization helps prevent costly damage from ice and ensures that the pool remains in good condition until it’s time to reopen in the warmer months.
Homeowners who neglect to close their pool correctly may face numerous issues, such as cracked pipes, damaged pumps, or algae growth due to unbalanced water. The process differs slightly depending on the type of pool—whether in-ground or above-ground—and the climate in the region. In colder areas, full winterization is essential, while in milder climates, some steps may be simplified. The primary goal is always to protect the pool and make the seasonal transition as safe and efficient as possible.
Why is balancing pool water chemistry important before closing?
Balancing water chemistry before closing the pool is essential because improper levels can lead to significant damage over the winter months. Imbalanced water can become corrosive or scale-forming, which can harm the pool’s surfaces, metal components, and equipment. Algae growth is also more likely in unbalanced water, especially if the chlorine level is too low. Properly balanced water preserves the overall integrity of the pool while reducing the risk of costly repairs in the future.
The main parameters to address include pH, alkalinity, calcium hardness, and chlorine levels. Typically, the pH should be maintained between 7.4 and 7.6, with alkalinity between 80 and 120 ppm, and calcium hardness adjusted based on the pool type. Adding a winterizing chemical kit can provide an extra layer of protection by stopping algae and bacteria growth throughout the colder season. Taking the time to test and adjust your pool’s chemistry ensures a smoother opening in spring and a cleaner environment to start the next swimming season.
How do you drain and winterize the plumbing and filtration system?
Draining and winterizing the plumbing and filtration system involves several key steps to prevent water from freezing and causing cracks or other damage. First, you should turn off the power to the pool pump and timer to prevent accidental startup. Then, the pump, filter, and heater must be drained, and the drain plugs or plugs provided by the manufacturer should be installed. It’s also important to open the pump basket, filter air relief valve, and any other valves on the system to allow all water to escape.
To ensure all water is removed from the lines, a pool cover blower or air compressor is typically used to blow out the plumbing lines. Once the lines are fully drained, a non-toxic pool antifreeze can be added as an extra precaution for in-ground pools, especially in very cold climates. After the equipment is adequately winterized, it’s a good idea to store any sensitive or removable items indoors. Covering the equipment protects it from moisture, snow, and debris accumulation over the winter months.
What should be done with the pool cover during the closing process?
Installing a proper pool cover is one of the most important steps in the closing process. A solid or mesh safety cover designed for winter use helps prevent debris, snow, and rain from entering the pool while also keeping animals and children safe. Before placing the cover, ensure that the water level is appropriate—slightly below the skimmer—and that all cleaning steps are completed to reduce the chance of algae growth under the cover.
After placing the cover, it should be secured using water bags, straps, or a cover pump, depending on the type of cover used. Solid covers usually require a pump to remove standing water, while mesh covers allow water to pass through. Regardless of the type, it is important to check the cover periodically during the winter to ensure it stays taut and free of damage. A well-maintained cover minimizes the effort required to open the pool and maintains water clarity through the closed season.
Can I close my pool myself, or should I hire a professional?
Closing a pool can be done either by the pool owner or a professional service, depending on experience, time, and equipment available. For those who are familiar with pool systems and have the necessary supplies, DIY winterization can save money and be a satisfying part of seasonal pool maintenance. However, it’s crucial to understand each step thoroughly and carry out the process accurately to avoid potential damage during the off-season.
Hiring a professional brings expertise and efficiency, especially for those who are inexperienced or have complex pool systems. A professional company will typically have the right tools, winterization chemicals, and knowledge to handle specific pool types and local climate conditions. While professional services may cost between $150 and $400, they provide peace of mind that the pool is well-protected for the winter months. Each person should weigh the costs, time, and risk of error before deciding which method is best.
When is the best time to close a pool for the winter?
The best time to close a pool is when the water temperature consistently drops below 65°F (18°C) and swimmer activity has decreased, usually in late fall before freezing weather arrives. Waiting too long to close the pool can increase the risk of algae blooms and equipment damage, especially after the first freeze. Planning to close the pool during a mild day with no rain or wind ensures that chemicals stay balanced and the cover can be applied correctly.
In regions that experience only mild winters, pools may remain open year-round, but in areas with frost and snow, it’s essential to close the pool well before temperatures fall below freezing. The timing also depends on whether the pool is heated or unheated. Most homeowners begin their winterization process when summer ends and the nights become consistently colder. Proper scheduling helps ensure a thorough and effective closing, protecting the investment for the next season.
What items and tools are needed to properly close a pool?
Several important items and tools are required to successfully close a pool for the winter. A winterizing chemical kit, test strips or a liquid test kit, pool antifreeze (non-toxic), and a pool cover are essential. Skimmers, brushes, and a pool vacuum are also needed to clean the pool thoroughly before closing. In addition, equipment such as a submersible pump or shop vac for draining and blowing out lines may be necessary depending on the pool type.
Other recommended tools include cover clips or tensioning straps, water bags for securing the cover, and a cover pump for removing excess water if using a solid cover. Winter plugs or gizzmos are used to prevent pipe expansion from freezing water and should be installed in the return jets and skimmer. For above-ground pools, air pillows may be used to absorb pressure from ice expansion. Gathering all these tools and materials in advance ensures a smooth and complete closing process without leaving anything vulnerable to damage.