Properly closing your pool for a harsh Canadian winter is the most important maintenance task of the year. A successful winterization prevents costly damage from freezing temperatures and ensures a much easier and cleaner opening in the spring. This guide provides a comprehensive checklist for winterizing both inground and above-ground pools.

One Week Before Closing:

• Balance the Water: Your final chemical test is crucial. Ensure the pH, alkalinity, and calcium hardness are all within their ideal ranges. Balanced water is less likely to cause staining or scaling over the winter. Do not add chlorine at this stage.

On Closing Day:

Step 1: Thoroughly Clean the Pool Skim, brush, and vacuum the pool one last time. Any organic debris left in the pool will decay over the winter, staining your liner and demanding a much more intensive clean-up in the spring.

Step 2: Add Winterizing Chemicals With the pump circulating, add your winterizing chemical kit. This typically includes a winter algaecide to prevent algae growth and a stain-and-scale prevention chemical to protect your pool’s surfaces. Allow the water to circulate for several hours to distribute the chemicals evenly.

Step 3: Lower the Water Level You must lower the water level to prevent freeze damage to your skimmer and return lines.

• For Inground Pools: Lower the water level to about 4-6 inches below the skimmer opening.
• For Above-Ground Pools: Lower the water level to just below the return jet fitting.

Step 4: Drain All Equipment This is the most critical step to prevent freeze-cracking.

• Turn off all power to the pool equipment at the breaker.
• Remove the drain plugs from your pump, filter, heater, and chlorinator. Store the plugs in the pump basket so you don’t lose them.
• Use a shop vacuum or air compressor to blow all water out of the plumbing lines, from the skimmer back to the equipment pad and from the pad back to the return jets. You should see air bubbles in the pool.
• Plug the lines at the pool side with winterizing expansion plugs.

Step 5: Install the Winter Cover Securely place your winter cover over the pool. Ensure it is tightly anchored with water bags (for inground pools) or a cable and winch (for above-ground pools). This will keep out sunlight and debris, which are the two main ingredients for an algae bloom. A tight fit also prevents wind from getting underneath and causing damage.

Your pool is now safely winterized. A thorough closing saves countless hours and dollars when it’s time to open again in the spring.