September is here, and while the days can still feel warm, the cooler nights and early hints of fall color are reminders that swimming season is ending. For Minnesota homeowners, this is the perfect time to prepare your pool for winter. Properly closing your pool not only prevents costly freeze damage but also makes spring opening smooth and stress-free.
When to Close Your Pool
The best time to shut down your pool is when the water temperature drops to around 60 degrees. That’s cool enough to slow algae growth while still giving you a safe window to winterize before freezing sets in. You’ll also want to pay attention to overnight lows—once those start dipping near or below freezing on a regular basis, it’s time. Another indicator is when the leaves begin to fall heavily, which adds unnecessary debris to your system if you wait too long.
Supplies You’ll Need
Before starting, make sure you have everything on hand:
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Water test kit
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Pool shock and algaecide
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Winterizing chemicals or antifreeze
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Return and skimmer plugs
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Air compressor or blower
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Winter cover (mesh or solid)
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Tools to remove ladders, rails, and accessories
Having these ready will make the process faster and easier.
Step-by-Step Pool Closing Checklist
1. Clean the pool
Skim, vacuum, and brush thoroughly. Don’t forget to clean skimmer baskets and filters so you’re starting with clear, debris-free water.
2. Balance the water chemistry
Adjust pH to 7.2–7.6 and alkalinity between 80–120 ppm. Add calcium hardness if needed. Shock the pool to kill bacteria and algae.
3. Lower the water level
For most pools, bring the water just below the skimmer. Mesh covers typically require slightly lower levels than solid covers, so follow your cover’s recommendation.
4. Blow out and plug lines
Use an air compressor or blower to clear water from return lines, skimmers, and the main drain. Insert plugs or add pool antifreeze to protect plumbing from freeze damage.
5. Winterize equipment
Drain pumps, filters, and heaters. Clean cartridges or backwash the filter as needed. Remove ladders, diving boards, and any accessories. Store them in a dry location.
6. Cover the pool securely
Install your safety cover tightly to prevent debris from entering. If you use a solid cover, consider adding a cover pump to keep rainwater or melted snow from pooling on top.
7. Shut down power
Turn off electrical equipment and gas heaters. Label valves and plugs for easier spring setup. Store leftover chemicals safely indoors.
Keeping an Eye on Things During Winter
Even with the pool closed, check on it every few weeks. Remove heavy snow or standing water from the cover, make sure anchors and straps are tight, and keep debris from building up along the edges. A little attention through the season helps prevent damage and ensures the cover does its job.
Common Mistakes to Avoid
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Closing too early, while the water is still warm—this can encourage algae growth.
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Forgetting to clear plumbing lines, which may crack during freezing.
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Leaving the cover loose or unsecured, allowing debris and snow to weigh it down.
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Using a tarp instead of a proper safety cover, which is less secure and less protective.
Wrapping Up
Closing your pool is always bittersweet, but doing it right is an investment in next year’s fun. September is the sweet spot for Minnesota homeowners. The water is cool, the evenings are crisp, and the first frosts are just around the corner. By winterizing your pool properly now, you will save yourself repairs, headaches, and extra costs when spring returns.
And remember, you do not have to tackle it alone. At Leisure Aquatic Products, we have been helping Minnesota families keep their backyards beautiful and protected for decades. Whether you need expert pool closing service, supplies, or just a friendly voice to walk you through the steps, our team is here to make it easy.
📞 Give Leisure Aquatic a call today at (507) 288-6289 and let us make sure your pool is closed the right way. When summer returns, all you will have to do is dive in.
