Top 10 Tips on Winterizing your Swimming Pool for Winter Season

Posted on October 3, 2025

As the leaves begin to turn and the chill of autumn air arrives, it's a bittersweet time for pool owners. The fun of summer is fading, but the necessary task of preparing your swimming pool for the winter season is at hand. Winterizing your pool properly is crucial for protecting your investment from harsh weather, preventing costly damage, and ensuring a smooth, sparkling opening next spring.

At PoolSupplyDelivery.com, we want to make this process as easy and effective as possible. Here are our Top 10 Tips on Winterizing your Swimming Pool for Winter Season:

1. Deep Clean Everything

Before you close your pool, give it a **thorough cleaning**. Skim all debris, brush the walls and floor, and vacuum thoroughly. The cleaner your water is now, the better your chances of opening a clear pool in the spring. Pay special attention to the waterline where grime tends to build up.

2. Balance the Water Chemistry

This is perhaps the most critical step. Test and adjust your water's **pH** (ideally 7.4–7.6), alkalinity, and calcium hardness. Once balanced, **shock the pool** with a powerful chlorine shock to kill any remaining bacteria and contaminants. Let the pump circulate the shocked water for several hours or overnight.

3. Add a Quality Winterizing Chemical Kit

After shocking, you need to add specific **winterizing chemicals**. These typically include an algaecide (to prevent algae growth under the cover), a stain and scale preventative, and a non-chlorine oxidizer. Follow the product instructions carefully and allow them to circulate for the recommended time (usually a few hours).

4. Lower the Water Level

For pools with tiled or vinyl coping, the water level typically needs to be lowered **below the skimmer and return lines**. This is necessary to prevent freeze damage to your plumbing and skimmer. Use a submersible pump or backwash the pool until the water is a few inches below the lowest line opening.

5. Blow Out and Plug the Plumbing

Water left in the pipes can freeze, expand, and crack your plumbing—leading to major repair costs. You must **remove all water from your lines**. Use an air compressor or a shop vac (set to blow) to force all water out of the skimmers, return lines, and equipment. Once clear, immediately **plug the lines** using threaded or expansion winter plugs.

6. Winterize the Equipment

Drain all water from your pump, filter, heater, and chlorinator. Open all **drain plugs** on the equipment and let them fully dry. Store smaller, valuable items (like the pump motor or chlorinator parts) indoors if possible. If leaving them outside, cover the equipment with a plastic tarp for protection.

7. Clean and Store Filter Elements

If you have a D.E. or cartridge filter, remove the grids or cartridges and **clean them thoroughly** with a dedicated filter cleaner. Allow them to dry completely before storing them in a safe, dry place. Sand filters just need a good backwash and drainage.

8. Remove and Store Accessories

Take out all removable items like **ladders, rails, pool toys, and pool cleaners**. Clean them well, dry them, and store them in a shed or garage to protect them from the elements and extend their lifespan.

9. Install a Secure Pool Cover

Your pool cover is your pool's best defense against winter debris and sunlight. Whether you use a solid winter cover, a mesh cover, or a safety cover, ensure it is **installed correctly and securely**. A tight seal minimizes debris entry and light penetration, both of which can encourage algae growth. Use an air pillow if you have a solid cover to catch rainwater and prevent ice formation directly on the water.

10. Inspect Periodically

While the pool is closed, **check on it every few weeks**. Ensure the cover remains secure, especially after heavy winds or snow. Top off air pillows if needed. Early detection of a cover failure or a leak can save you a huge headache and potentially a green mess in the spring.