How to Close a Pool for Winter: Step-by-Step Guide for Pool Owners

Pool without cover

If you’re a first-time pool owner or simply need a refresher on how to close a pool for winter, you’re in the right place! Preparing your pool for the cold months—also known as winterizing a pool—is an essential part of pool maintenance. Done properly, winterizing protects your swimming pool from costly freeze damage, prevents algae growth, and ensures you’ll have a clean, ready-to-use pool when spring arrives.

Below, we’ll cover the best time to close your pool, the key pool winterizing steps, and pro tips to make the process easier.

When Should You Close Your Pool?

The best time to begin pool winterization is in early to mid-fall, when daytime temperatures consistently stay below 65°F. At this point, algae growth slows down, making it the perfect time to cover your pool. Closing too early—when the water is still warm—can lead to algae problems and extra work when reopening in spring.

Pool water test kit

Step 1: Balance Your Pool Water

Before shutting down your swimming pool for winter, test and adjust your water chemistry. Properly balanced water helps prevent staining, scaling, and corrosion during the off-season.

Check these key levels with a reliable pool test kit:

• pH: Ideal range is 7.2–7.6 PPM. Adjust using pH increasers or decreasers.

• Total Alkalinity: Aim for about 100 PPM to help stabilize your pH.

• Calcium Hardness: Keep between 100–400 PPM to prevent corrosion or scale buildup.

💡 Pro Tip: Use specialized winterizing pool chemicals to keep your water chemistry stable until spring.

Step 2: Shock Your Pool

Before covering, give your pool a strong chlorine shock treatment. This kills bacteria, prevents algae, and keeps your water fresh. Bring chlorine levels up to 10–12 PPM, then let them return to the normal range of 1.5–3.5 PPM before proceeding.

Step 3: Remove and Clean Pool Equipment

Take out and thoroughly clean all pool accessories, including:

• Skimmer baskets

• Ladders and handrails

• Vacuums, pool cleaners, and hoses

• Heaters, slides, and wall fittings

Allow equipment to dry fully and store in a safe, dry place. Also, skim the pool and remove leaves or debris with a net or pool rake.

Step 4: Lower the Water Level

Use a filter pump or submersible pump to lower your pool water about 4–6 inches below the lowest return line or skimmer. For above-ground pools, you can remove the skimmer entirely.

Step 5: Drain Pool Equipment

Your pump, filter, heater, and chlorinator must be drained to prevent freeze damage. Remove the drain plugs, empty the water, and store plugs separately.

• Sand & DE Filters: Backwash, disconnect, and store dry.

• Cartridge Filters: Clean thoroughly and check for damage.

Never re-plug drained equipment—if water gets inside, it could freeze and crack.

Step 6: Empty the Chemical Feeder

Drain and empty your chemical feeder completely. Leaving chemicals inside during pool winterization can corrode equipment. Always wear gloves and goggles when handling chemicals.

Step 7: Add a Winter Pool Cover

The final step is covering your pool with a durable winter pool cover. Look for one that blocks sunlight, keeps out debris, and prevents algae growth.

For above-ground pools, consider using air pillows beneath the cover. These relieve pressure from ice expansion, protect your pool walls, and keep water and debris from pooling in the center.

Pool cover

Final Thoughts: Protect Your Pool Investment

Learning how to close a pool for winter is one of the best ways to protect your swimming pool investment. By balancing your water, shocking your pool, draining equipment, and covering it properly, you’ll avoid costly repairs and enjoy an easier pool opening in spring.

Whether you have an above-ground pool or an inground pool, following these pool closing steps will save you time, money, and hassle—so you can look forward to your first swim next summer!