Winterizing an In-Ground Pool for Freezing Conditions

winter pool cover with water bags

As summer winds down, it is time to start getting your pool ready for the cold winter months. Properly winterizing your pool will protect your equipment from ice damage, keep your water clean, and save you time and money when opening your pool in the spring. Winterizing your pool may seem complicated but, with a little preparation, it can be a very simple and pain-free process. Leslie’s has compiled a set of step-by-step instructions to help you safely and effectively winterize your pool.

If you live in a climate that will see long periods of freezing temperatures, and you own an in-ground pool, follow these easy-to-follow instructions to help you close your pool at the end of the season.

  1. One week prior to closing your pool, add 14 fluid ounces of Pool Magic + PHOSfree for every 10,000 gallons of water directly into the skimmer.
  2. Brush and vacuum the pool thoroughly to remove all dirt, leaves and debris.

  1. To prevent metal stains, add MetalFree and Leslie’s Stain and Scale 2. For every 20,000 gallons, add one liter of MetalFree and one quart (32 ounces) of Leslies Stain and Scale 2 by pouring it around the perimeter of the pool.
  2. Adjust the Total Alkalinity to the proper level. Total Alkalinity should be in the 80 - 120 ppm range for plaster pools, and the 120-140 range for vinyl-lined pools. To easily adjust Total Alkalinity, use Leslie’s Alkalinity Up by broadcasting around the perimeter of the pool. Just one pound of Leslie’s Alkalinity Up will increase the Total Alkalinity of 10,000 gallons of water by 10 ppm.
  3. Adjust the pH to the proper level. For all pools, pH should be between 7.4 and 7.6. Leslie’s Soda Ash quickly raises a pool’s pH, Just 6 ounces raises the pH level of 10,000 gallons by 0.2. For plaster pools, broadcast around the perimeter of your pool. For vinyl-lined pools, mix with water in a large bucket before adding it to your pool.
  4. To help protect your pool, adjust the Calcium Hardness to 200-400 ppm using Leslie’s Hardness Plus. Adding 1 ¼ pounds of Leslie’s Hardness Plus for every 10,000 gallons of water will increase the Calcium Hardness by 10 ppm.
  5. Add one quart (32 ounces) of Leslie's Algae Control per 25,000 gallons by mixing with water in a large bucket and pouring it around the perimeter of the pool. Wait one hour before following the next step.

  1. Shock the pool with Leslie's Fresh 'N Clear at the rate of two pounds per 10,000 gallons by broadcasting the product around the perimeter of the pool.

leslies pool shock

  1. Bring the chlorine to an appropriate level - between 1.5-3.0 ppm.
  2. Let the pump run for at least one complete cycle after adding chemicals. Backwash or manually clean the filter.
  3. Lower the water level below the skimmer and all return lines (normally about 18 inches below the tile line). Alternatively, a Blowout Extension may be used to remove water from the lines.
  4. Remove the drain plugs from the pump strainer basket housing, the pump volute, the filter tank, and the heater. Keep the drain plugs handy, they will be used in Step 16.
  5. Drain the automatic pool cleaner's booster pump and the automatic chlorinator, if you use one.
  6. Turn off the main power supply and remove the ON and OFF trippers from the time clock.
  7. Position the multi-port valve handle between any two settings. This will ensure all ports are partially open to allow for freeze expansion.
  8. Place all the drain plugs in the strainer basket of the pump and replace the strainer cover.
  9. When the water has completely drained out of the plumbing lines, put Winterizing Plugs into the return line and skimmer lines.
  10. Add Pool Line Antifreeze to all lines. Antifreeze should be added at the rate of one gallon per 10 feet of pipe.
  11. Place a Gizzmo into the skimmer to seal the skimmer pipe and absorb any ice pressure.
  12. Refill the pool back to between 4-6 inches below the skimmer inlet in vinyl-lined pools or 4-6 inches below the tile line in plaster pools.
  13. Remove all non-permanent articles such as ladders, hoses, over-the-top skimmers, etc. Remove the automatic pool cleaner and drain it completely. Lay the hoses out straight in a non-freezing location.
  14. Inflate and tie Air Pillows to a stationary object. An average-sized pool, 16’ x 32’, typically requires 2-3 air pillows. If you are using multiple pillows, tie them together using the grommets located on the pillow's corners.
  15. For plaster pools only: tie a Floating Chlorinator to one of the air pillows. It should be set at its lowest rate of feed.
  16. If the coping or deck of the pool has a rough surface or edge, protect the pool cover by placing foam, old solar cover material or other similar soft materials around the perimeter of the pool.
  17. Cover the pool using a Safety Cover or Winter Cover and Leaf Net.

leslie's pool covers

  1. If necessary, fill and place Water Bags or Hold-Em-Downs around the edge of the pool. In normal conditions, these can be placed 18 inches apart, but in windy areas, they should be placed end-to-end.
  2. During the winter season, check the chemical balance every two weeks, and inspect the pool water by pulling back the cover slightly. If staining or scaling is beginning to develop, bring a sample of your water into your nearest Leslie’s location.

Leslie's Free 10-Point Water Test

If you have any questions about how to properly prepare your pool for the winter months that were not answered above, please call or visit your local Leslie's store.