Winterizing an In-Ground Pool for Non-Freezing Conditions

winterizing an in-ground pool

As the 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 will help 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 rarely has temperatures dip below freezing, 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. Add Pool Magic + PHOSfree

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.

Leslie's BLOG pool chemicals

2. Thoroughly Clean Pool

Brush and vacuum the pool thoroughly to remove all dirt, leaves, and debris.

Leslie's BLOG pool cleaning attachments

3. Fill Pool Water

Fill the pool to the top, almost to the point of overflowing.

4. Add Stain Remover

To prevent metal stains, add MetalFree and Leslie’s Stain and Scale Remove. 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.

5. Adjust Total Alkalinity Level

Adjust the Total Alkalinity to the proper level. Total Alkalinity should be in the 80 - 120 ppm range for plaster pools, and in the 120-140 range for vinyl-lined pools. To easily adjust Total Alkalinity, use Leslie’s Alkalinity Up by broadcasting it 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.

6. Adjust pH Level

Adjust the pH to the proper level. For all pools, the 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 it around the perimeter of your pool. For vinyl-lined pools, mix it with water in a large bucket before adding it to your pool.

Leslie's BLOG water test kits

7. Adjust Calcium Level

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.

8. Add Algae Control

Add one quart (32 ounces) of Leslie's Algae Control per 25,000 gallons by mixing it with water in a large bucket and then pouring around the perimeter of your pool. Wait one hour before following the next step.


9. Add Pool Shock

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 your pool.

Leslie's BLOG pool shock

10. Adjust Chlorine Level

Bring the chlorine to an appropriate level - between 1.5-3.0 ppm.

11. Run the Pool Pump

Let the pump run for at least one complete cycle after adding chemicals. This is usually 4-8 hours. Backwash or manually clean the filter.

12. Set the Time Clock

Set the time clock to run the filter for 2-4 hours per day.

13. Install Pool Cover

Cover the pool using a Safety Cover or Winter Cover and Leaf Net.

Leslie's BLOG pool covers

14. Attach Water Bags

If necessary, fill and place Water Bags or Winter Cover Blocks 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.

15. Mid-Winter Maintenance

During the winter season, check the chemical balance every two weeks using a test kit, 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 for more information.