How to Winterize an Above Ground Pool | Close It Right The First Time

Winterizing an above ground pool protects it from freezing damage by balancing water, lowering the level, and securing a cover.

The secret to a clean spring opening is doing a thorough job in the fall. A surprising number of pool owners skip the final steps and pay for it with cracked fittings and stained liners in April. Success with how to winterize an above ground pool depends on following an order: clean, balance, drain, disconnect, cover.

What Order Should You Close An Above Ground Pool?

Work from the water outward. The physical steps are consistent across pool brands, though the exact plumbing details vary.

Start by removing ladders, toys, and debris. Then brush the walls and vacuum the floor so organic matter doesn’t sit all winter — it can discolor water and damage liners over months. Test the water and bring chemistry into range before adding any winterizing products.

Water Chemistry: What Levels Matter Before Closing?

Balanced water prevents staining, scale, and algae from taking hold while the pool sits idle. The target numbers are the same ones you chase all summer, but getting them right before closing matters more.

• Alkalinity: 80–120 ppm, per The Spruce’s closing guidance
• pH: 7.4–7.6
• Calcium hardness: 200–400 ppm

After balancing, add your winterizing chemicals. The Spa and pool industry generally recommends shocking the pool and adding an algaecide or winterizer product. Wait about 1 hour between each chemical, advises The Pool Factory’s closing process, then run the filter system for another 3–4 hours after the last dose so everything circulates.

If you’re shopping for the supplies, our tested roundup of the best above ground pool winterizing kits compares the top all-in-one options and what each includes.

How To Drain, Disconnect, And Store Equipment

Freezing water expands, and trapped water is what cracks pumps and hoses. This step is where most winter damage actually happens.

Lower the water level to 4 to 6 inches below the skimmer opening, or just below the return fitting depending on your plumbing layout. Above-ground pools generally follow the same cleaning and chemistry steps as in-ground pools, but instead of blowing out the lines,

Disconnect, drain, and store hoses, pumps, and filters indoors or in a dry, protected location. If your pump must stay outside, drain it fully and follow the manufacturer’s storage guidance, because prolonged winter exposure can damage the equipment.

Covering: Air Pillow And Securing The Tarp

An air pillow sits under the center of the cover to buffer ice expansion and keep the cover from sagging into the water. The Pool Factory recommends inflating it to about 60–70% of its capacity. Some pool owners treat it as optional, so use one only if it’s compatible with your cover system.

Drape the winter cover over the pool and secure it with the cable, winch, or clips that came with it. A loose cover lets the wind shift it and debris pile up all season. Check the fit after the first strong wind.

The most common mistakes people make include skipping the chemistry balance, leaving organic debris in the pool, forgetting to drain hoses, and covering without securing the tarp tightly. Timing also matters:

Your pool’s exact plumbing closure depends on whether it has a skimmer, return fittings, a sand filter, cartridge filter, or D.E. filter. Check the manufacturer’s manual for your specific model, and always follow the dosage on your chemical product labels — published amounts differ by brand and pool volume.