As the crisp autumn air arrives and the swimming season draws to a close, a critical task appears on every pool owner’s checklist: winterizing. This essential piece of pool maintenance isn’t just about throwing a cover on and calling it a day. It’s a comprehensive process that protects your valuable investment from freezing temperatures, prevents costly damage, and sets you up for an effortless opening come springtime.
Many pool owners dread this process, fearing it’s too complex. But what if you had a complete, easy-to-follow step-by-step guide on winterize a pool?
This guide provides just that. We’ll walk you through every action, from water chemistry to covering, and share our top pool care tips. We’ll also reveal the professional’s secret to ensuring your pool is in tip-top shape when you pull back the cover—a secret that makes “swampy spring openings” a thing of the past.
Let’s dive into how to winterize a pool correctly.
Why Is Winterizing Your Pool So Important?
Skipping your pool closing tasks is a gamble, and the stakes are high. Water expands when it freezes, and that expansion exerts incredible force. If water freezes inside your pool’s plumbing, filter, pump, or skimmers, it can lead to catastrophic damage.
Proper winterization prevents:
- Cracked Pipes: The most common and expensive repair.
- Damaged Equipment: A frozen pump or filter casing can mean a full replacement.
- Staining & Scaling: Unbalanced water can stain your pool liner or plaster.
- Algae Blooms: A poorly closed pool is a breeding ground for algae, turning your spring opening into a green, costly nightmare.
In short, a few hours of work now saves you thousands of dollars and countless headaches later.
When Should You Winterize Your Pool?
Timing is crucial. Don’t close your pool too early, as warm water (even under a cover) can still promote algae growth. The Golden Rule: Wait until the ambient temperature is consistently below 65°F (18°C).
This ensures the water is cold enough to inhibit algae and bacteria, making your winterizing chemicals last longer.
A Step-by-Step Guide on Winterize a Pool
Ready to get started? We’ve broken down the entire process into 7 manageable steps. Follow this guide, and you’ll be a pro in no time.
Step 1: Gather Your Supplies
Before you begin, do a quick inventory. There’s nothing worse than getting halfway through a process only to find you’re missing a key component.
You will need:
- A pool water test kit
- Pool balancing chemicals (pH increaser/decreaser, alkalinity increaser, calcium hardness increaser)
- Pool shock (preferably a non-chlorine or winterizing shock)
- Winter algaecide
- Skimmer, pool brush, and pool vacuum
- Shop-vac or air compressor (for blowing out lines)
- Winterizing plugs (for return jets and skimmers)
- Non-toxic pool antifreeze (for very cold climates)
- A high-quality winter pool cover and (if needed) air pillows
Step 2: Clean the Pool (One Last Time)
You want your pool to be as clean as possible before it’s “put to bed” for the winter. Any debris left in the pool will decay, consume your chemicals, and stain your surfaces.
- Skim: Remove all floating leaves, bugs, and debris from the surface.
- Brush: Thoroughly brush the walls, steps, and floor of the pool to dislodge any clinging dirt or early-stage algae.
- Vacuum: Give the pool a final, comprehensive vacuuming. If you have a lot of debris, you may want to vacuum to “waste” (if your filter allows) to avoid clogging the filter.
Step 3: Balance Your Water Chemistry
This is arguably the most important step for preventing stains, scaling, and algae. Do this 3-5 days before you plan to add the final winterizing chemicals.
Run your pump and test your water. Adjust your chemicals to reach these winterizing targets:
- pH: 7.4 – 7.6
- Total Alkalinity: 80 – 120 ppm (parts per million)
- Calcium Hardness: 200 – 400 ppm
- Chlorine: 1 – 3 ppm
Pro-Tip: Properly balanced water is less likely to become corrosive or form scale during the cold, stagnant winter months. Don’t skip this!
Step 4: Add Winterizing Chemicals
With your water balanced, it’s time for the final chemical cocktail.
- Shock the Pool: Add a heavy dose of pool shock. This super-chlorinates the water, killing any lingering bacteria, algae, or organic contaminants. Use a shock specifically formulated for pool closings, often a non-chlorine shock, which won’t degrade your pool cover. Follow the manufacturer’s instructions for the dose size based on your pool’s gallonage.
- Add Algaecide: After the shock has circulated and chlorine levels have returned to normal (1-3 ppm), add a winter-specific algaecide. This is a long-lasting formula that prevents algae spores from blooming.
Let the pump circulate all chemicals for at least 8-12 hours (or as directed) to ensure they are fully dispersed.
Step 5: Lower the Water Level
The goal here is to get the water level below the skimmer and return jets to prevent freezing and cracking.
- For Mesh Covers: Lower the water 12-18 inches below the skimmer.
- For Solid Covers: Lower the water 3-6 inches below the skimmer (just below the return jets).
You can lower the water using your filter’s “waste” setting or by using a submersible pump.
Step 6: Winterize Your Plumbing & Equipment
This is the most technical part of the process, but it’s critical for preventing freeze damage.
- Backwash & Clean Filter: Give your filter one last, thorough cleaning. Backwash your sand or D.E. filter, or deep-clean your cartridge filter.
- Drain Equipment: Disconnect your pump, filter, heater, and any chlorinators. Remove all drain plugs from these components to let all water escape. Store the plugs in the pump’s strainer basket so you don’t lose them!
- Blow Out the Lines: This is the most important of all tips to winterize a pool. You must remove all water from the plumbing lines.
- Use a high-powered shop-vac or air compressor set to “blow.”
- Force air through the skimmer lines until you see bubbles coming out of the return jets.
- Plug the return jets as the air is blowing out to create a water-free seal.
- Repeat this process for the main drain (if you have one) and all return lines.
- Plug Everything: Securely install winterizing plugs in all return jets and skimmer openings.
- Add Antifreeze (Optional): In climates where deep freezes are common, pouring a small amount of non-toxic pool antifreeze down the lines after blowing them out provides extra insurance.
Step 7: Install Your Winter Cover
The final step! A good winter cover is your pool’s shield against sunlight, leaves, and debris.
- For Above-Ground Pools: Use an overlapping cover secured with a cable and winch. Use air pillows in the center to support the cover and prevent a solid sheet of ice from forming.
- For Inground Pools: A safety cover (mesh or solid) is the best option. These are anchored into the deck and provide a strong, safe barrier. If using a standard tarp-style cover, use water bags or blocks to hold it securely in place.
The Secret to a Flawless Spring Opening (Beyond Winterizing)
You’ve followed every step. You’ve balanced, shocked, and covered. You should be guaranteed a crystal-clear pool in the spring, right?
Unfortunately, many pool owners do all this work only to pull back the cover and find cloudy, hazy, or green-tinged water. The problem? Microscopic contaminants and phosphates (algae food) that survive the winter.
This is where your pool care tips get a high-tech upgrade.
Make DualPool Your First Step for a Tip-Top Pool Season
Your goal for winterizing isn’t just to prevent damage—it’s to have an easy opening. The condition of your pool in the spring is your final report card. To get an A+, you need DualPool.
DualPool is a cutting-edge, self-dosing, 2-in-1 pool clarifier that’s the perfect product to ensure your pool is in tip-top shape come pool season.
While traditional winterizing chemicals fight a defensive battle, DualPool is what you use the moment you open your pool to win the war on cloudy water.
Here’s why DualPool is the perfect partner to your winterizing efforts:
- It Attacks the Root Problem: When you open your pool, the water is filled with fine, suspended particles and phosphates that winter chemicals couldn’t handle. DualPool’s patent-pending technology specifically targets and removes these contaminants.
- Two-Stage Cleaning: DualPool works in two stages. It first tackles suspended solids, metals, and nutrients. Then, it acts as a long-term polish, ensuring your water doesn’t just get clear, it stays clear.
- It’s Non-Toxic & Safe: After a long winter, you don’t want to load your pool with more harsh chemicals. DualPool is made with non-toxic, NSF-approved ingredients. It’s safe for your family, pets, and pool surfaces.
- Effortless to Use: After you’ve done the hard work of re-installing your pump and getting water circulating, your job is done. Simply place DualPool in your skimmer basket. Its self-dosing technology works with your pump to continuously clarify the water with zero effort from you.
Think of it this way: Winterizing is how you protect your pool. DualPool is how you perfect your water.
When you open your pool in the spring, don’t just shock it and hope for the best. Start your circulation, add your DualPool, and watch as it transforms your “winter-worn” water into a crystal-clear oasis faster than ever. It’s the ultimate final step to your pool maintenance routine, making all your hard work from the fall pay off.
Conclusion: Winterize Like a Pro, Open Like a Genius
Following this step-by-step guide on how to winterize a pool is not just a seasonal chore; it’s the most important investment you can make in the life and health of your pool. By taking the time to clean, balance, and drain your equipment properly, you are guaranteeing an easy and, most importantly, inexpensive spring opening.
And when that spring finally arrives, you can be the pool owner who smiles, knowing that with DualPool in your skimmer, you’ll be swimming in crystal-clear water while others are still battling the “spring swamp.”