Winterizing your pool is an essential step in protecting your investment and ensuring that your pool remains in top condition during the off-season. Whether you live in a region with freezing temperatures or mild winters, properly closing your pool can save you time, money, and headaches when it's time to open it again in the spring.
In this comprehensive guide, we’ll walk you through everything you need to know about winterizing your pool, from when to start and what supplies you need to detailed step-by-step instructions for both inground and above-ground pools.
Why Winterizing Your Pool Matters
Leaving your pool open and untreated during the winter can result in:
-
Cracked or burst pipes due to frozen water
-
Stained or damaged surfaces
-
Algae blooms and bacterial growth
-
Expensive repairs and labor-intensive spring cleanups
By taking the time to winterize your pool properly, you’re preserving the integrity of your equipment and water chemistry and ensuring a quicker, easier reopening.
When to Start Winterizing Your Pool
The best time to winterize your pool is when the average water temperature drops to below 65°F (18°C) and you are no longer using the pool regularly. In colder climates, this is usually in late September to early November. Waiting too long can result in freezing temperatures damaging your equipment.
What You’ll Need
Here’s a checklist of essential items to have on hand:
-
Pool cover (solid or mesh)
-
Pool closing chemicals (shock, algaecide, pH balancer, etc.)
-
Water testing kit or strips
-
Pool antifreeze (for lines in freezing climates)
-
Air compressor or shop vac (for blowing out lines)
-
Skimmer plugs and return line plugs (a.k.a. freeze plugs)
-
Pool brush and vacuum
-
Winterizing plugs and gizmos (for skimmers)
-
Pool cover pump (optional but helpful)
Step-by-Step: How to Winterize Your Pool
1. Clean the Pool Thoroughly
Remove all leaves, dirt, and debris from the pool. Vacuum the bottom, brush the walls, and skim the surface. Cleaning thoroughly helps prevent staining and algae growth over the winter.
2. Balance the Water Chemistry
Test your water and adjust the levels to the recommended winterizing ranges:
-
pH: 7.4 – 7.6
-
Alkalinity: 80 – 120 ppm
-
Calcium Hardness: 200 – 400 ppm
-
Chlorine: 1 – 3 ppm
Balanced water protects your pool surfaces and equipment from corrosion and scaling during the winter.
3. Add Winterizing Chemicals
Shock the pool with a chlorine or non-chlorine shock treatment to kill any lingering bacteria or algae. Then, add an algaecide and a winterizing chemical kit (if using one) that typically includes a stain preventer and clarifier. Run the pump for 24 hours to fully circulate the chemicals.
4. Lower the Water Level
-
Inground pools: Lower the water level below the skimmer and return lines by 4–6 inches. This prevents water from entering and freezing in the plumbing.
-
Above-ground pools: Drain water to just below the skimmer and return fittings. Some models allow for skimmer covers instead.
Avoid draining the pool completely—doing so can cause structural damage.
5. Drain and Blow Out the Plumbing Lines
If you live in a freezing climate, this step is critical:
-
Use an air compressor or shop vac to blow water out of the pump, filter, heater, and plumbing lines.
-
Plug return lines with freeze plugs, and use gizmos in skimmers to absorb expansion from ice.
-
Add pool antifreeze to the lines if you’re unsure all water has been cleared (never use automotive antifreeze).
6. Remove and Store Equipment
Take out ladders, diving boards, slides, and any accessories. Clean and store them in a dry area. Disconnect and drain the pump, filter, heater, and chlorinator. Sand and DE filters should be emptied and rinsed. Store your pump and motor indoors if possible.
7. Cover the Pool Securely
Use a high-quality pool safety cover or winter cover to protect the water from debris, sunlight, and animals. Make sure the cover fits tightly and is anchored properly:
-
Inground pools: Use water bags, cover clips, or a cover cable and winch.
-
Above-ground pools: Use a cable and winch system, plus air pillows to relieve pressure from ice expansion.
Inspect the cover occasionally during winter and remove accumulated water or debris.
Winterizing Saltwater Pools
Saltwater pools follow the same general process but with a few extra tips:
-
Test and balance salt levels before closing.
-
Remove and store the salt cell indoors to avoid damage from freezing.
-
Clean the cell with a mild acid solution if there’s calcium buildup.
Common Mistakes to Avoid
-
Closing too early: Warm water can cause algae blooms even if covered.
-
Skipping chemical balancing: Imbalanced water leads to staining and corrosion.
-
Leaving water in lines: In freezing areas, this can cause cracked pipes.
-
Using a damaged cover: Tears or holes will let debris in, defeating the purpose.
-
Forgetting to check on the pool: Even during winter, check the cover monthly.
Bonus Tips for an Easy Spring Opening
-
Take notes or photos of how everything is disconnected and plugged.
-
Store all small parts (plugs, fittings, etc.) in a labeled bag or container.
-
Mark your calendar to inspect the pool and cover monthly throughout winter.
Conclusion
Winterizing your pool may feel like a big job, but it’s well worth the effort. By following these steps and doing a thorough job now, you’ll protect your pool and equipment from damage, reduce your spring maintenance, and enjoy a hassle-free opening when swim season returns.
If you're unsure about any part of the process—or have complex equipment like heaters or automatic cleaners—it’s always a good idea to consult a pool professional.
