When Should You Close Your Swimming Pool?
The general rule we suggest at Crush Pools for closing a swimming pool in Ontario is to close it as late as possible, ideally sometime after Thanksgiving. This helps ensure the water will be clear when the pool is opened in the Spring.
Why You Shouldn’t Close Your Pool Too Early
Closing a swimming pool too early in Ontario carries several risks, primarily related to potential algae growth and increased cleanup efforts in the spring.
If you close your pool in September when the weather can still be warm, and the water is not circulating, there’s a greater chance of algae forming, leading to the water turning green. This will result in additional chemical and cleaning costs in the spring to get the water clear. While some people close early to save on pump costs, the cleanup effort and expenses for chemicals later can outweigh these initial savings.
The best time to close a swimming pool in Ontario to prevent algae growth is when the weather is consistently below 15°C. In Ontario, this typically means sometime after Thanksgiving but before temperatures go below freezing. Closing at this time prevents algae growth and makes opening in the spring much easier.
If you take our advice and wait as long as possible you can usually keep your pool running well into October as long as the temperatures are not below freezing. During this time you also get the added benefit of looking at your beautiful pool instead of a winter cover, another reason to keep your pool open longer.
The Leaf Dilemma: Scooping vs Clean Water
One of the biggest reasons people close their pool early is leaves. By late September and October, the trees in Ontario are shedding like crazy, and scooping them out of the pool every day can feel like a full-time job.
Here’s the tradeoff:
- Close early – fewer leaves to scoop, but higher chance of algae and murky water in spring.
- Close later – more time with the skimmer net, but your spring opening will be much cleaner and cheaper.
Think of it this way you can either spend a few minutes scooping in the fall or spend hours shocking, scrubbing, and balancing water in the spring. We’d pick scooping every time.
Why You Shouldn’t Leave Your Pool Open Past Thanksgiving
On the flip side, waiting too long can backfire. Once we hit freezing nights, any leftover water in your lines, pump, or filter can freeze and crack the equipment. If we get an early cold snap or you lose power during a storm, you’re risking expensive repairs.
Signs It’s Time to Close Your Pool
- Water temp is consistently below freezing.
- You know you’re done using it for the year.
- Night temperatures are dipping close to freezing.
If you’re hitting these marks, it’s time to close.
Insurance & Why Proper Closings Matter in Ontario
Here’s something most pool owners don’t realize: in Ontario, some home insurance providers may require proof that your pool was properly closed if you ever make a claim for winter damage. That means if frozen pipes or cracked equipment lead to costly repairs, your claim could be denied if the insurer thinks your pool wasn’t winterized.
On top of that, many manufacturer warranties on pumps, heaters, and liners are only valid if the pool was closed by a professional. If equipment is damaged because it wasn’t winterized correctly, the warranty usually won’t cover the replacement.
Pre-Closing Checklist
Here’s what goes into a proper pool closing (at a high level):
- Inspect your liner, cover, and equipment for damage.
- Balance water chemistry (pH, alkalinity, calcium hardness).
- Shock and add algaecide to keep water clear all winter.
- Lower the water level below skimmers/returns.
- Blow out the plumbing lines and protect your skimmer (using a Gizzmo or antifreeze).
- Remove ladders, toys, vacuums, and anything else that shouldn’t freeze.
- Install a quality cover ideally a safety cover, which keeps debris out, blocks sunlight (less algae), and keeps kids and pets safe.
DIY vs Professional Pool Closing
You can close a pool yourself but if you miss a step, it could cost you a new liner, cracked plumbing, or stained walls in spring. At Crush, our licensed and seasoned technicians handle everything by the book. We only book a limited number of pools each day so you never get rushed service. That’s how we guarantee your pool is protected all winter.
Make Your Pool Opening Easier
Closing your pool isn’t just about shutting it down, it’s about setting yourself up for an easy opening next year. Close too early and you’ll fight algae. Close too late and you risk equipment damage. Close at the right time, with the right steps, and you’ll pull that cover off in spring to a pool that’s crystal clear and ready to enjoy.
Why We Love Pool Safety Covers
We’ve mentioned safety covers a few times, but they deserve their own spotlight. A proper safety cover does a lot more than keep out leaves. They help keep your pool cleaner (and safer).
Here’s why we recommend them:
- Blocks sunlight – less algae growth, which means cleaner water in spring.
- Keeps kids and pets safe – unlike tarp covers, safety covers are built to hold weight.
- Cleaner backyard look – they fit tight across the pool, so no sagging tarp full of rainwater and leaves.
- Longer lifespan – safety covers last much longer than standard winter tarps when maintained properly.
Ready to close your pool? Check out our Pool Closing Services and book your appointment before it’s too late!
