5 Easy Steps to Winterize Your Pool

Pool in snow covered yard

If you live in an area where temperatures frequently dip below or stay below freezing throughout the winter, it’s smart to close your pool before the first freeze. By doing so, you’re taking steps to protect your pool from harsh winter weather and temperature fluctuations. This will ensure your pool is ready for family fun next spring.

Here are 5 easy steps that are important for preparing your pool for the cold, winter weather.

1. Prepare The Pool

Start by brushing the walls, emptying skimmer baskets and vacuuming, right down to the pool floor. Cleaning your pool before you close it for winter will mean less cleaning in the spring!

Next, you’ll want to balance the water chemistry. Balancing the water chemistry helps to protect against scaling and corrosion over the winter. Using a water test kit, adjust the water to the recommended levels of pH, total alkalinity, calcium (hardness) and chlorination.  This is a good time to add a winterization chemical kit. These kits put high levels of chlorine and  algaecide in the water to prepare it for the long winter months ahead. You should consult with a pool professional to identify the right kit for your pool. Find a dealer here.

Finally, you need to drain the water to below the skimmer mouth, but DO NOT EMPTY THE POOL! The expansion of the soil under the pool as the water in the soil freezes can cause your pool to lift right out of the ground; it needs the weight of some water to keep it firmly in place.

2. Prepare The Pump, Filter, Skimmers and Heater

Disconnect your pump and filter. Make sure all water is completely drained from the pump. Remove the drain plugs from it, note, there may be one or two, which will trap water inside. Once you've drained the pump, turn it on for just a second or two (no more—the seal is vulnerable to damage) to expel any remaining water from the impeller.

If you have a heater, remove any drain plugs and drain it. To make sure there is no standing water inside, blow it out with a compressor or shop vac.

Remove all return jet fittings, yes, the entire fitting. If one cracks while removing it, don't panic! You can get a replacement come spring.  Remove all skimmer baskets.

Remove the filter hoses. Spray the cartridge filter elements and D.E. (diatomaceous earth) grids with Filter Cleaner, then rinse them clean with a garden hose. If you have a sand filter, clean it by backwashing. For D.E. filters, drain the filter tanks and leave the backwash valve open. DO NOT acid wash a D.E. filter at pool closing time; wait until spring.

Open the drain at the bottom of the filter to let out any water in the filter outlet; be sure to open the air relief valve on top if you have one. Put the multiport valve in the closed or "winter" position—blow the water out of it if necessary—and remove the pressure gauge.

Store any small plugs or parts you have removed from the pump, heater and filter in the pump basket, so they're easy to find next year. Put jet fittings and any other items that you remove in one of the skimmer baskets or with the other parts the pump basket to avoid loss.

3. Blow Out Water Lines

Water expands as it freezes, creating severe pressure that can crack pipes, fittings or other parts. Unscrew and loosen any quick-disconnect fittings or unions at your pump and filter system, then blow out the pipes. A wet-dry shop vacuum or air compressor is ideal for this. Force the air from your pump down the skimmer and through the skimmer or "suction side" pipes.

Blow out the return plumbing by hooking up your compressor to the return lines at the filter system, or by screwing it into the pump's drain plug. Continue blowing air through the pipes until air bubbles emerge from the return jets; then tightly plug the fitting below the water line. Close up all exposed pipes with plugs.

Also it is important to blow out the main drain line. There’s no diving necessary to plug up the drain pipe! When you see bubbles coming out of the drain, plug the pipe on your end or close the gate valve. This creates an "air lock" in the line, ensuring that no more water can enter it from the pool side, which protects the main drain line.

4. Secure a Flotation Device and Pool Cover

Before you put on a winter pool cover, you'll want to install a flotation device in the center of the pool. Your flotation device doesn’t have to be fancy, but it is a very important part of winterizing a pool! The float balances the rainwater and ice sure to form on your pool's cover over the winter. Even more importantly, it eases pressure on the pool walls because ice buildup pushes inward on the flotation device and not outward on the walls.

The winter cover is important for both the pool and the people around it. It's stronger than a summer cover, both to withstand the weight of snow and ice, and to protect people or pets from accidentally falling through the cover into the water. Do not use a cover that is ripped beyond repair.

Stretch the cover over the pool, black side down. If any sharp points are protruding from beneath, cushion them with cardboard or rags. Then stretch the cover very tightly across the pool, which can be a two to three person job. Run a strong wire through the holes around the perimeter of the cover, and snug it up using a wrench so the cover stays down in during winter storms.

5. Properly Stow Deck Equipment

Any ropes or floats that were removed from your pool should be stored with the rest of the supplies. Store diving boards and ladders in the shed or garage. 

Properly winterizing your pool will make it that much easier to get the fun started again when swimming season comes back around. Work with your pool professional to take all the right steps to make sure your pool is ready for the colder weather.