After a fun summer in the pool, you’ll want to make sure you “winterize” it properly before closing it up for the season. Taking these steps is a part of proper pool maintenance and will help ensure that your pool is in tip-top condition when you open it back up again.
When to Start Prepping Your Pool for Winter
Start the winterizing process after the season is over, when the temperature consistently dips down to 65 degrees F or lower.
If you start too early, you may encounter problems with algae, which thrives in warmer temps. Give yourself a week to complete this process, as several steps need to be performed over the course of a few days.
Steps for Winterizing an In-Ground Pool
Follow the steps below to prep your pool for the winter months.
Step 1: Remove pool accessories
Start by removing accessories such as skimmer baskets, cleaners, ladders, steps, and solar blankets from the pool. Hose off any dirt and algae, let the items dry, and store them in a safe place for the winter.
Step 2: Deep clean the pool
Make sure your pool is as clean as possible by removing all leaves, silt, and other debris. This will make it easier to balance the water chemistry and prevent mold and algae growth. Use skim nets to clean the pool’s surface, and a pool vacuum to remove all debris from the bottom. Then thoroughly brush the pool’s floor and sides.
Keep your clean pool covered between the next steps so that it doesn’t get dirty again while you’re in the middle of winterizing.
Step 3: Adjust the water chemistry
A week before closing the pool, test the water chemistry to make sure the alkalinity is between 80 and 150 parts per million (ppm), the pH level is between 7.2 and 7.6, the calcium hardness level is between 175 and 225 ppm, and the chlorine level is between 1 ppm and 3 ppm.
Adjust as necessary, making sure you balance the alkalinity before you work on the pH level. Err on the higher side for each of these measurements, as the levels will naturally decrease as time passes.
Step 4: Lower the water level
If you aren’t using a skimmer cover and you live in an area where the water will freeze during the winter, you’ll need to lower the water level of your pool before closing it up.
The water level should be about a foot below the skimmer if you have a mesh cover, and about half a foot below the skimmer for solid covers. Depending on how you’re removing the water from your pool, this process may take a day or two.
Step 5: Drain and store the equipment
It’s important to drain all the equipment so the water won’t expand and cause damage when temperatures fall below freezing.
Clear the water from the pool lines using a blower, then plug them up with expansion plugs. If you want to be extra careful about preventing burst pipes, consider adding pool antifreeze.
Drain every filter, pump, and heater (most of this equipment will have drain plugs). In addition, all filters should be removed and cleaned. If possible, store the filter and pump indoors for the winter.
Step 6: Add shock and algaecide
Before covering up the pool, add shock, which kills bacteria, and algaecide, which kills algae. You may have to do this a few days before you officially close the pool, depending on the type of shock you buy. Follow the package directions, and make sure you distribute the chemicals around the pool evenly, instead of pouring them in just one area. If you’re using chlorine shock (vs. non-chlorine shock), don’t add it at the same time as the algaecide.
Step 7: Cover the pool
It’s finally time to put the cover on the pool! There are two types of covers: safety covers and winter covers. Safety covers must be anchored down, and they provide the greatest protection from debris, as well as people or animals accidentally falling in.
Winter covers offer less protection, but you won’t have to deal with the extra step of securing them. No matter which type of cover you use, make sure it’s tight-fitting and doesn’t have any holes or tears.
Winterizing an Above-Ground Pool
The steps above can also be applied to winterizing an above-ground pool, except that in step 5, you’ll want to disconnect the hoses and plug the outlets (instead of clearing water from the pool lines, which only applies to in-ground pools).
Additionally, before you put a cover on an above-ground pool, install an air pillow at the center (and keep it anchored there) to absorb the expansion of ice within the pool and keep the snow that piles up on the cover from exerting too much pressure.