When summer days fade and temperatures begin to drop, it’s time to winterize your pool. Taking this step protects your pool from freezing temperatures and reduces the risk of encountering problems when you use it next season. Whether you have an in-ground or above-ground pool, we’ll explain how to winterize your pool, the common mistakes you’ll want to avoid, and what it may cost you.
When To Winterize Your Pool
You’ll want to start the winterization process between late summer and early fall when the temperature is consistently below 65 degrees Fahrenheit. If you close your pool too early, you risk the formation of algae, but if you wait until it’s too cold, freezing temperatures can damage your pool.
When it’s time to close your pool, plan to take at least a week to complete the process. This will provide you with enough time to do a thorough cleaning, balance chemicals, and prepare your equipment.
Tools And Supplies For Pool Winterization
Collect all the necessary tools to make it easier and faster to close your pool. You’ll need the following items to ensure the process goes smoothly:
- Blower or shop vac (for clearing water lines)
- Expansion plugs
- Filter cleaner
- Pool brush
- Pool cover (safety or winter cover)
- Pool vacuum
- Skimmer net
- Submersible pump (for lowering water level)
- Water testing kit
You’ll also need the following supplies to complete the winterization process:
- Air pillow (for above-ground pools)
- Algaecide
- Alkalinity increaser
- pH increaser or decreaser
- Pool antifreeze (if necessary)
- Pool shock
- Winterizing chemical kit
Step-By-Step Guide To Winterizing an In-Ground Pool
Once you’ve collected all the necessary items, you’re ready to begin. Follow the steps below to properly prepare your pool for winter.
Remove Pool Accessories
Start by removing accessories such as skimmer baskets, cleaners, ladders, steps, and solar blankets from the pool. Hose off any dirt and algae, let the items dry, then store them in a safe place for the winter.
Deep Clean
Remove all leaves, silt, and other debris. This will make it easier to balance the water chemistry and prevent mold and algae growth. Use skim nets to clean the pool’s surface, and a pool vacuum to remove all debris from the bottom. Then thoroughly brush the pool’s floor and sides.
Keep your clean pool covered between the next steps so that it doesn’t get dirty again while you’re winterizing.
Test and Adjust Your Water Chemistry
First, clean the pool and check the water’s chemistry. Maintaining the proper chemical balance not only protects swimmers, but it safeguards your pool against damage. Test and adjust to the following levels:
- Alkalinity: 80–120 parts per million (ppm)
- Calcium hardness: 200–400 ppm
- Chlorine: 2–4 ppm
- pH: 7.2–7.6
You can control corrosion, scaling, and staining of pool surfaces by balancing the alkalinity before the pH level.
Lower the Water Level
If you aren’t using a skimmer cover and you live in an area where the water will freeze during the winter, you’ll need to lower the water level of your pool before closing it up.
The water level should be about a foot below the skimmer if you have a mesh cover, and about 6 inches below the skimmer for solid covers. Depending on how you remove the water from your pool, this process may take a day or two.
Drain, Disconnect, and Store
Drain all the equipment so water won’t expand and cause damage when temperatures fall below freezing. Clear the water from the pool lines using a blower, then plug them up with expansion plugs. If you want to be extra careful about preventing burst pipes, consider adding pool antifreeze.
To avoid damage to your pool’s external plumbing system, disconnect the hoses from the pump, filter, and skimmer. Drain the hoses completely and store them in a dry place.
Add Shock and Algaecide
Add shock, which kills bacteria, and algaecide, which kills algae. You may have to do this a few days before you officially close the pool, depending on the type of shock you buy. Follow the package directions, and make sure you distribute the chemicals around the pool evenly, instead of pouring them in just one area. If you’re using chlorine shock (vs. non-chlorine shock), don’t add it at the same time as the algaecide.
Cover the Pool
There are two types of covers, safety covers and winter covers. Safety covers must be anchored down, and they provide the greatest protection from debris, as well as preventing people or animals from accidentally falling in.
Winter covers offer less protection, but you won’t have to deal with the extra step of securing them. No matter which type of cover you use, make sure it’s tight-fitting and doesn’t have any holes or tears.
Winterizing Above-Ground Pools
The process of winterizing an above-ground pool is similar to closing an in-ground pool, but there are some key differences. Since an above-ground pool has a distinct structure, it responds differently to winter conditions.
Use An Air Pillow
Above-ground pools need air pillows to create a gap between the water and cover during the winter. As the pool water freezes, the ice will expand toward the pillow, reducing pressure on the pool walls. An air pillow also prevents snow and rain from accumulating on the pool cover—avoiding collapsing or sagging.
How To Winterize A Saltwater Pool
Saltwater pools may require less maintenance than traditional chlorine pools, but you still have to winterize them. Consult your owner’s manual for instructions based on your specific saltwater pool model. However, the following tips are standard for most saltwater pools:
- Adjust salt levels: Test the saltwater pool’s salt levels according to the manufacturer’s recommendations. Maintaining the proper salt levels will help prevent corrosion and make it easier to open the following spring or summer. Most salt levels fall between 2700 and 3400 ppm, but check your owner’s manual for the correct range.
- Clean the salt cell: Your salt cell, or chlorine generator, sanitizes your pool. Before closing your pool for the season, remove and inspect the salt cell. Drain water from it and clean it with a mild acid solution or the cleanser your manufacturer recommends if you find dirt, debris, or buildup. Store it indoors if you can.
Common Mistakes To Avoid When Winterizing Your Pool
There are some common mistakes homeowners make when they’re closing their pools. Steer clear of the following:
- Closing the pool too early: Cosing your pool before the temperature is consistently below 65 degrees Fahrenheit could lead to algae growth.
- Failing to balance the chemicals: A chemical imbalance can cause corrosion, scaling, or algae formation.
- Neglecting to clean thoroughly: Without a deep clean, your pool may be ripe with algae, dirt, and other contaminants that will make it harder to open next swimming season.
- Forgetting to drain the pool or equipment: Not lowering the pool’s water level or leaving excess water in the pumps, filters or other components can cause it to expand when it freezes, damaging your pool or its equipment.
Troubleshooting Winter Pool Problems
You may still encounter problems during the winter even if you’ve properly closed your pool. Addressing these issues quickly will help you prevent further damage and more costly repairs. Here are two issues to watch for:
- Cover problems: Tears, sagging, and holes could signal significant water accumulation or damage. You should consider replacing your cover to protect your pool interior and keep anyone or anything from falling into it.
- Frozen pipes: If you suspect you have frozen pipes, contact a pool technician instead of trying to thaw them yourself.
Our Conclusion
Winterizing your pool includes cleaning it, balancing the water’s chemistry, and draining water from your pool and equipment. By closing your pool properly, you’ll reduce the risk of damage from freezing temperatures, algae growth, and other contaminants. Most homeowners can complete this project themselves, but consider hiring a professional if you’re inexperienced or notice a problem with your pool.