As the warm days disappear and the cooler ones roll in it’s time to start thinking about winterising your pool. Whether you’ve had months of summer fun or just dipped in now and then proper winterisation is key to keeping your pool in good nick through the off season.
Not winterising your pool can lead to some nasty surprises come spring like cracked pipes, murky water, algae blooms and damaged equipment. But with a little planning you can avoid the costly repairs and make reopening your pool next season a breeze.
You’ll learn when to start, how to winterise your pool step by step and what common mistakes to avoid to keep everything in great shape for next season.
When Should I Winterise My Swimming Pool?
Timing is everything when it comes to swimming pool winterisation. The general rule is to start when the water temperature drops below 15°C (around 60°F). At this point algae growth slows down and it’s safe to start closing up without risking a green pool.
In cooler climates this might be early autumn, in milder climates you can hold off a little longer. If you’re in a temperate climate you can wait until the water temperature drops below 18°C (64°F) before starting to winterise. If you’re in a hot climate you can wait until the water temperature drops below 20°C (68°F).
In cooler regions, this might be in early autumn, while in milder climates, you can hold off a little longer. If you’re in a temperate part of Australia, such as Melbourne or Sydney, aim to winterise your pool before the chill really sets in, usually around late April to early May.
6 Steps to Winterising Your Swimming Pool
Step 1: Clean your pool
Start by removing all leaves, debris and dirt by skimming the surface. Then brush the walls and vacuum the floor.
Leaving debris or dirt in your pool over winter can cause staining and disrupt your water chemistry, so clean now to save yourself a headache later.
Step 2: Balance the water chemistry
Before adding any swimming pool winteriser products, test and balance your water. Here’s what to check:
| Parameter | Ideal Range |
| pH level | 7.2 – 7.6 |
| Alkalinity | 80 – 120 ppm |
| Calcium hardness | 180 – 220 ppm |
| Free chlorine | 1 – 3 ppm |
Balancing your pool water helps protect your surface, liner, and equipment over the winter period.
Helpful tip: add a winter algaecide (or long-life algaecide) to prevent algae growth while your pool is out of use.
Step 3: Reduce the water level
For vinyl-lined pools, lower the water just below the skimmer to avoid pulling the liner. For concrete or fibreglass pools, lower the level about 10 to 15 cm below the skimmer. This will help prevent freeze damage to skimmers, returns and tile work.
Step 4: Drain and store pool equipment
Remove and clean removable equipment such as hoses, pumps, heaters and filters. For filters, give them a good rinse or backwash to clear out summer grime and impurities. If you live in a freezing climate, blow out plumbing lines with a wet/dry vacuum or air compressor and then plug them to prevent water re-entry and freeze damage. Even though the pool is closed, running your pump for a short time during winter will help prevent algae growth and keep your water clearer.
Step 5: Add chemicals
Shock your pool before closing to kill any remaining bacteria or algae. Consider adding a clarifier to help settle debris to the bottom for easier cleaning next season. For pools using chlorine tablets, put them in a floater to keep chlorine levels up throughout winter. Adjust the amount of chlorine or salt chlorinator output for the lower bather load and cooler temps..
Step 6: Cover your pool
A good quality pool cover is essential to protect your water and keep out debris. Solid covers block all light which helps reduce algae growth, mesh covers allow water to pass through but prevent larger debris from entering. Safety covers are a great option if you have kids or pets, extra protection.
Make sure to secure your cover with water bags, weights or a tensioning system to prevent it from shifting in the wind and always check for any tears or wear before putting the cover on.
Get Your Pool Ready for Spring
Winterising your pool may seem like a hassle now but it’s a smart way to protect your asset and avoid costly repairs later. By following the right process your pool will be in great shape during the off season and open smoothly when the weather warms up.
