Unfortunately the summer has ended again and you need to know how to close your pool for winter. Maybe you’ve forgotten what you did last year or you want to close it better this time so that opening it next year will be a breeze.
The level of winterization depends on where you live.
Pool Owners, who are lucky enough to live in tropical climates, never close the pool as it can be utilized the whole year. Sub-tropical areas provide for longer pool usage but during winter the water will be too cool for swimming without heating. Pools in this climate are the easiest to maintain through winter.
Pools located in temperate climates have a shorter swimming season and need more preparation to close for the winter season.
If you are in a snow climate where the temperature drops below freezing you need to properly close your pool for the winter to preserve its condition and prevent damage to the pool.
Table of Contents
When to Close Your Pool
Normally most people prepare their pool for winter sometime in the fall (autumn) when the water is too cool for swimming. The leaves are falling from the trees, the sky is grey, the sun is weak and they don’t want to spend any more time or money cleaning the pool.
It’s time to begin the winterization process to preserve your pool until the next spring or summer season.
What Happens If You Don’t Winterize Your Pool?
If you live in very cool climate where there is the possibly of frosts or snow and you don’t winterize the pool you will experience damage to the filtration system and plumping caused by water freezing and expanding.
In a temperate region, if you don’t correctly winterize the pool, you may remove the pool cover in spring to be greeted with smelly, green swamp water caused by an algae bloom. Then you have to drain the pool and start over. And nobody wants to go through that process.
If you leave the pool uncovered you will need to keep up a cleaning routine during winter to prevent the pool water deteriorating and looking like a swamp. You may be able to run the pump for less hours each day as the pool is not being used but you will still need to test and balance the water. Your pool water still needs sanitization with chlorine either from a chlorinator or manually distributed.
How to Close Your Pool for Winter
Clean the Pool
The first thing to prepare your pool for winter is to give the pool a good clean. I am assuming your pool is reasonably clean to start with. Attach your pool brush to the telescoping pole and brush the walls and steps in a downwards motion. Allow the debris to settle on the bottom. Next manually vacuum the bottom of the pool to remove all the sediment. Turn the valve to waste water so you don’t clog up the filter. Remember to turn the valve back again afterwards.
Clean the Filtration Equipment
Now it’s important to clean the skimmer basket, pump basket and filter. If you have a sand filter backwash it. If you have a filter cartridge, remove it and hose the debris away. Check the filter cartridge and replace if it’s still soiled after cleaning or showing signs of deterioration.
Remove the drain plus from the filter to drain out water. Store the plugs in the pump basket so that you don’t lose them.
Algaecide
Add a dose of Algaecide to the pool water to prevent algae forming under the cover. Run the pool pump for at least 4 hours.
Test the Water
I recommend testing the water in two locations – one from each end of the pool. Collect water samples from elbow depth and use test strips or a test kit. The pool water must be correctly balanced before trying to close the pool. You don’t want any scale, corrosion or other damage to occur while closed under a pool cover.
Shock the Pool
Add a single dose of pool shock following the manufacturer’s instructions and run the pool pump for at least 4 hours and re-test the water to ensure it’s balanced. Never add algaecide and shock at the same time. Ensure that they’re used a day or two apart as they may react adversely together.
Winterizing the Pool
All regions
If your pool test shows a high level of metals in the water you should add a dose of metal sequestrate which suspends any metals in the water and doesn’t allow metals to settle on pool surfaces and cause unsightly stains.
Sub-Tropical Region
If you are in a sub-tropical region you don’t need to close your pool for the winter.
Simply continue to run the pool pump daily and cover the pool to prevent leaves and other debris entering the water. The water should stay relatively clean and clear without too much effort on your part. If your pool is not salt water chlorinated you will have to continue adding chlorine to the pool manually. If you don’t have a cover you will still need to regularly clean the pool yourself or use a cleaning robot.
Temperate Region
In this region you have a choice as to whether you keep the pool pump in operation or close it down. It is highly recommended to cover the pool tightly to protect it from the elements. There is no need to drain any water from the pool.
Snow-Belt Region
As the air temperature will drop below freezing you need to drain any water in the pool plumbing pipes and filter equipment as it will freeze, expand and burst the pipes.
How far down do you drain your pool for winter?
For an inground pool, usually you need to drain the water down to below the bottom of the outlet jets in the pool so that there is no water remaining in the skimmer box and pipes to the filtration system. Turn the valve on your pump unit to waste water and run the pump until the water is at the desired level.
I recommend hiring a professional pool contractor to blow out the pipes and seal them for the winter to prevent freezing water bursting pipes.
The alternative to draining water from the pipes is to add antifreeze to the pipes. Please use pool antifreeze that is non-toxic and designed specifically for swimming pools. Do not use car radiator antifreeze – it’s toxic.
Remove the salt water chlorinator unit and store it for the winter.
Drain the whole filtration system of water otherwise it will freeze, expand and crack.
Turn off all power to the pump and filter.
Add a “Winter Pill” to the pool water. These contain a slow-release sanitizer that takes months to dissolve and are designed to be placed in a closed pool under a cover. Don’t use a chlorine tablet in a floater as these dissolve unevenly and don’t work well under a cover.
Finally, cover the pool. A full safety cover is best when you have lowered the water level. During the off- season you may need to clean leaves, water or snow off the pool cover with a broom.
Store Pool Accessories
Store all other accessories inside out of the cold including ladders, hoses, skimmer baskets, cleaning equipment, etc.
How To Close Above-Ground Pools for Winter
Cool Temperate or Snow-belt Region
If you live in a cool temperate or snow-belt region I recommend draining your above-ground pool for winter. It’s just easier to drain the pool and cover everything than go through a full winterization procedure. If you leave water in an above-ground pool it may freeze and exert pressure on the walls to buckle them or tear the lining. It’s just not worth the risk.
When you cover the pool make sure snow and water can slide off the top of the pool. The best way to achieve this is to place an object at the center of the pool to elevate the pool cover. When it rains or snows it will run off on to the surrounding ground.
In the spring opening the pool is simply a matter of filling it again from your town water supply. Then balance the pool chemistry and set up the pump and filter.
Warm Temperate or Sub-Tropical Region
If you live in a warmer climate leave the water in the pool and follow the procedure above for in-ground pools.
You will need to lower the water level below the skimmer box to prevent freezing damage to the box. Lowering the water any further may put extra strain on your cover when water and snow collect on top.
Install a pool pillow under the center of the pool cover to lift up and hold the cover in an elevated position. This prevents rain and snow build-up on the pool cover as it slides off to the sides. The pillow floats on the water so you can always see where the water level is when your pool is covered. If the water freezes the pillow will still sit on the ice at the center of the pool.
Please read our post on How to Prepare Your Pool for Summer
Conclusion
It might seem like a real chore to close your pool for the winter but you only close your pool once a year. The first year may be daunting but after that it’s a relatively straightforward process.
Please work through our checklist to make sure you complete all the necessary tasks to guarantee your pool is properly winterized.
If you followed our recommended closing process to winterize your pool then opening in the spring should be a trouble-free process.
Good luck for the spring!
