How to Winterize an Above-Ground Pool

Above-Ground Swimming Pool

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Project Overview
  • Working Time: 2 - 3 hrs
  • Total Time: 2 - 3 hrs
  • Skill Level: Beginner
  • Estimated Cost: $25 to $50

Your above-ground swimming pool gets used a lot during the warm-weather seasons for swimming and all sorts of fun. So, it makes sense to protect your investment and to be ready for the next swim season, and winterizing your above-ground swimming pool is the best way to do that.

Winterizing an above-ground pool might look like it requires a long list of steps, but most of the activities are quick and easy to do. Plus, the list overlaps with many of your regular pool maintenance tasks. With less than half a day's work before winter begins, you'll be able to enjoy the upcoming swim season as soon as it comes.

What Is Winterizing an Above-Ground Pool?

Winterizing an above-ground pool is the process of readying your pool for upcoming seasons of unfavorable weather when the pool will not be used. Winterizing prevents damage to the pool and helps the pool to be ready for swimming sooner—and in better condition—when spring arrives.

Many pool-closing techniques are simply the final pool maintenance activities of the season, such as skimming the water. Other techniques are specific to winter and a dormant season, such as treating the water with special chemicals.

Why It's Essential to Winterize Your Above-Ground Pool

  • Protect Against Freeze Events: Whether it's frost or a hard freeze, temperatures that drop below 32°F are freeze events that can damage the pool's frame, liner, pipes, and lines.
  • Avoid Algae Blooms: Your pool is more prone to algae during the warm, sunny months than it is during the winter. Even so, pool water left unattended and untreated for months at a time will grow algae, too.
  • Prevent Damage to Equipment: When the weather turns harsh, all delicate pieces—from the housing and motor to the electrical wiring and hoses—are under enormous stress from temperature drops, snow, ice, and rain.
  • Keep Pool Clean: Winter storms, wind, and months of disuse are avenues for dirt and larger debris to build up in your above-ground pool. Keeping the pool clean in advance is easier than cleaning a dirty pool at the end of winter.

When to Winterize an Above-Ground Pool

In most areas, you need to winterize your above-ground pool around mid-October or when the pool water dips below 65°F and consistently remains below that point.

Do not winterize the pool too early, or the winterizing chemicals will lose their potency before the end of the winter. Also, if you wait until temperatures are cooler to winterize, algae is kept in check by the cooler water.


Pools in temperate climates that are used year-round do not need to be winterized.

Winterizing Above-Ground vs. In-Ground Pools

Winterizing an above-ground pool shares most of the characteristics of winterizing an in-ground pool, with just a few differences.

  • Water capacity of an in-ground pool is greater than that of an above-ground pool, so make sure that you follow all pool chemicals' instructions carefully.
  • When cleaning scale, never use a pumice stone with above-ground pools. Instead, use a nylon brush.
  • Make sure you buy a winter pool cover made specifically for above-ground pools, as well as one that suits the exact size, shape, and type of your pool.

What You'll Need

Equipment / Tools

  • Skimmer net or leaf rake
  • Pool vacuum
  • Pool brush
  • 5-gallon bucket
  • Hand siphon or a small submersible pump


  • Winterizing inlet plug
  • Algaecide
  • Chlorine or non-chlorine shock
  • Pool cover
  • Air pillows or supports for pool cover
  • Tarp
  • Test kit for chlorine, alkalinity, pH, and total hardness
  • Stain and scale remover
  • Winterizing pill


  1. Prevent Stains and Scaling

    In the last two weeks of pool use, add stain and scale remover to the pool water. Turn on the pump and add 8 ounces per 8,000 gallons of stain and scale remover, or as directed by the product instructions.

  2. Manage Phosphate Levels

    In the last week of swim season, add phosphate treatment, as needed, in order to maintain regular phosphate levels. As usual, add the treatment to the pool skimmer while it is running. Consult the instructions on the treatment bottle for proper levels.

  3. Remove Pool Toys and Equipment

    Remove all floating toys and pool equipment such as ladders from in or around the pool. Store indoors in the garage or a shed. Leave the filter, skimmer, hoses, and all other equipment related to cleaning in place for now.

  4. Skim Pool

    With the extension skimmer net or leaf rake, remove all debris such as leaves floating on top of the pool. For anything large that has sunk to the bottom of the pool that's easy to grab, take it out with the skimmer net or leaf rake.

  5. Brush Pool

    Use the pool brush on the extension pole to brush all surfaces, especially the inner walls of the pool.

  6. Vacuum Pool

    With the pool vacuum, thoroughly remove the rest of the leaves and other debris remaining at the bottom of the pool.

  7. Balance Alkalinity, pH, and Calcium Hardness

    As usual, test and balance out your pool's alkalinity, pH, and calcium hardness levels:

    • Alkalinity: Aim for 80‐120 ppm. If the water is below 80 ppm, increase the level until it is within range.
    • pH Levels: The pH levels should be between 7.4 and 7.6.
    • Calcium Hardness: Bring the hardness levels to between 200 and 400 ppm.
  8. Add Algae Preventative

    Add 4 ounces of liquid algae control for every 4,000 to 5,000 gallons of pool water or as directed. Mix the control with cool water in a clean bucket. Turn on the pool filter. Slowly add the algae preventative around the perimeter of the pool. Be careful not to add too much to any single location. Let the filter pump run for an hour or two.

  9. Shock Pool Water

    With the pump running from the algae preventative, apply shock treatment to the pool water. Spread the shock treatment around evenly. Use 1 pound of shock treatment per 5,000 gallons or as directed on the product instructions.

  10. Raise Chlorine Level

    With the filter still running, raise the chlorine level in the pool water to around 3 ppm. Try to stay between 2 and 4 ppm. Use 1 1/2 ounces of product for every 5,000 gallons or as directed. Let the filter run for four to six hours.

  11. Remove Filter

    Turn off the pump and unplug it. Remove the filter and clean it out.

  12. Add Winterizing Pill

    Add the floating winterizing pill. Make sure that the pill contains a clarifier, scale inhibitor, stain inhibitor, and enzyme enhancement.

    What Is a Winter Pill?

    A winter pill or winterizing pill is a plastic lozenge that floats under the pool cover and contains chemicals that maintain pool water quality throughout the winter. A winter pill will usually last up to six months.

  13. Drop Water Level Below Skimmer

    Use a hand siphon or a small submersible pump to draw water, lowering the water level to about 4 inches below the skimmer.

  14. Add Winterizing Plug

    Unscrew the inlet fitting on the inside wall of the pool. Replace it with the winterizing plug. Put the inlet fitting aside in a safe place for reuse.

  15. Disconnect and Drain Hoses

    Remove all hoses and drain them completely until dry inside. Drain the chlorine feeder.

  16. Add Pool Cover Supports

    Add three or four air pillows or other floating devices to hold the pool cover off of the water. Tie the cover supports with thin nylon rope to keep them stationary in the water.

  17. Add Pool Cover

    With an assistant, draw the pool cover across the pool. Secure the cover to the pool frame with clips or with weighted wall bags.

  18. Turn off Power

    Shut off the GFCI outlet on the outlet body. Also, shut off electricity to the outlet at the circuit breaker.

  19. Turn off Water

    If you have a water shut-off to the outside located in the house, turn this off. If not, tightly turn off the faucet and add a winter cover over it.

  20. Store Items

    Store all remaining items indoors, if possible. They should be kept out of freezing conditions. This includes all hoses, skimmers, floats, automatic pool cleaner, and skimmers. If you cannot store the items indoors, keep the large items outdoors but cover them with a tarp.

Tips for Winterizing an Above-Ground Pool

  • Never use a tarp as a pool cover. Always use a pool cover designed for the size and shape of your pool.
  • If the pool has many deciduous trees above it, use a leaf net on top of the pool cover.
  • Don't skip the air pillows/supports for the cover. These unlock the cover from the water in the event of freezing.
  • Lift the cover every couple of weeks to make sure that algae is kept in check. Add algaecide if algae is beginning to grow.

When to Call a Professional

Though winterizing is not difficult, it does require several steps. If you find yourself in the window of time to winterize your pool but pressed for time, call your local pool service company for help.