In Ottawa, where winter temperatures can swing from mild autumn chills to sudden deep freezes, proper pool winterization isn’t optional; it’s essential. When water freezes, it expands, which can crack pipes, damage skimmers, and compromise your pool’s structure. Draining too much or too little can also cause serious issues come spring. A well-balanced approach keeps your pool protected throughout months of ice and snow, so you’re not faced with costly repairs later.
But should you drain a pool in the winter? The answer to this question can depend on the type of pool you have, whether above or in-ground. In most cases, you shouldn’t drain it completely. This guide reviews what you should know about draining your pool and when you should call the professionals.
Do You Need to Drain Your Pool Every Winter?
Not draining your pool to a certain water level can have concerning results. When the weather gets cold, if your pool is filled up too high, the water can freeze, damaging the internal lines and various components. You don’t need to drain your pool completely heading into winter, but you should drain the water line below the skimmer, or you run the risk of issues.
It’s important to note that you shouldn’t overdrain your pool, either. Empty pools are susceptible to structural stress due to hydrostatic pressure, particularly in areas with high groundwater levels, such as the Rideau River region. When the surrounding soil becomes saturated, the upward pressure can push a completely drained in-ground pool upward or even cause it to “float.” Maintaining a proper water balance keeps your pool stabilized against ground pressure throughout the season.
If you’re unsure of how to close your pool, it’s a good idea to have a professional handle winterizing your pool for you.
When Should You Drain Your Pool?
In Canada, snow can come well before winter arrives in December. In Ottawa and much of Eastern Ontario, it is recommended to begin winterizing your pool before the first frost, typically around mid-to-late October, depending on the year. Once temperatures consistently drop below 15°C, it’s time to start. Waiting too long increases the risk of frozen plumbing or equipment damage if an early cold snap arrives.
Ideally, you want to have your pool winterized before the first snowfall, as this is when temperatures can reach freezing. In addition to draining your pool water to an acceptable water level, you need to perform maintenance on your pool lines. Doing this type of maintenance before the first frost of the year is ideal.
How to Drain Your Pool for Canadian Winters
There are many steps required to tackle a pool winterization properly. While you might be comfortable tackling these yourself, consider reaching out to our professional team if you have any questions or concerns. Alternatively, we’d be happy to close your pool for you as part of our services!
Step 1: Remove All Equipment and Clean Your Pool
Remove all your pool equipment and perform a routine cleaning to ensure your pool is free of debris and objects that may clog your water lines. Take out ladders, skimmer baskets, toys, and accessories. Neglecting this step can lead to heavy staining or algae buildup that’s difficult to remove later.
Step 2: Disconnect and Drain Your Pump and Filter
Water left inside your pump or filter can freeze, expand, and crack the housing. Disconnect and drain your water pump and filter before choosing a safe, dry, and warm place to store them for the winter.
Step 3: Drain and Store Your Heater
Pool heaters must be fully drained to prevent internal cracking caused by frozen water. Drain and store your pool heater, if you own one, according to the manufacturer’s instructions and check connections in the spring before restarting.
Step 4: Drain Your Pool and Blow Out the Lines
Drain the pool to the right water level and then blow out all of your water lines. For in-ground pools, lower the water to about 10 to 20 cm (4 to 8 inches) below the skimmer. For above-ground pools, just below the return jet is usually sufficient. Blowing out your lines removes residual water, preventing freeze damage. Avoid using antifreeze on your water lines because this can create more problems for you during the spring.
Step 5: Plug the Skimmer and Return Lines
Plug your skimmer so that new water and ice don’t enter it throughout the winter. If this step is skipped, new water entering the skimmer can freeze and expand, leading to cracks.
Step 6: Balance Your Water Chemistry
Check to see if your chemicals (water pH, alkalinity, and calcium hardness) are balanced, and perform the tasks needed to balance them before putting your pool cover on. Balanced water prevents corrosion, scaling, and algae formation while the pool sits idle.
Step 7: Cover the Pool Securely
Place your pool cover over the water to protect the pool during harsh and inclement weather. A solid winter cover keeps debris and precipitation out while reducing UV exposure that can damage liners.
Other Winterization Tips
Here are some other tips to consider when closing your pool:
- There are winter-specific chemicals you can add to your pool water to maintain the proper pH throughout the season.
- Your specific type of pool may require different winterization steps than others, so check your manufacturer’s instructions when winterizing on your own.
- Any temperature below 15 degrees Celsius is ideal for closing your pool.
- Choose a pool cover built for Canadian winters. Reinforced safety covers are designed to handle heavy snow loads without tearing or sagging.
- Check the cover’s tension after major snowfalls. Safely clear excess snow or water to prevent stretching or tearing.
- Inspect your pool deck and coping for cracks or loose grout before winter sets in. Sealing small gaps now helps prevent larger freeze-thaw damage later.
- Keep records of your closing date, water chemistry, and maintenance steps. These details can help ensure a smoother, faster opening in spring.
Calling on the Experts
Winterizing a pool takes more than just lowering the water. If you have any of the following situations, calling a professional is highly recommended:
- Saltwater pools, as these require extra attention to prevent salt crystallization in lines and equipment.
- Pools with attached spas or waterfalls, where plumbing systems are more complex.
- Pools with known leaks or liner concerns, where draining too much water could cause collapse or shifting.
- New homeowners who are unfamiliar with their pool’s plumbing layout or closing process.
If you want to ensure your pool is winterized the right way, contact us at Benson Pools. Our team is happy to handle all of the details and keep your pool protected so that it’s safe and ready to use once spring arrives.
