Leaves are changing, temperatures are cooling, and, for certain climates, that means it’s the sad time of year to close your swimming pool.
As we reminisce on this year’s pool season and transition into the colder months, it’s time to winterize your pool so it will be prepped and ready for the next pool season. Closing your pool is a simple process that either you or your pool professional can do. If you plan on closing your own pool, make sure you follow these 10 pool closing steps to avoid expensive repairs in the spring.
How to Close Your Pool For Winter
Follow these steps to help guide you through closing your pool for the winter:
1. Start One Week Prior To Closing
We recommend starting to winterize your pool one week before you would like your pool to be completely closed. Timing is important to this first step, as closing your pool when water temperatures are higher could lead to algae growth. Wait until the water stays cool day and night, because warm water under a cover can still grow algae. To begin the closing process, you can add a phosphate remover to help cut down the nutrients algae feed on.
2. Clean Your Pool Thoroughly
Make sure to clean your pool thoroughly by skimming all debris from the pool surface, emptying all skimmer baskets, vacuuming the floor and brushing the pool’s walls. Cleaning your pool before closing makes your spring pool opening even easier.
3. Balance Your Water Chemistry
This is one of the most important pool closing tips. Unbalanced pool chemistry can damage or destroy your pool surfaces and equipment. Use these ideal ranges from the Oregon Health Authority’s pool water quality standards (OAR 333-062-1000, checked November 2026) as a guide, and follow your pool builder’s targets for your surface if they differ:
- pH: 7.2 to 7.6
- Total alkalinity: 60 to 180 ppm
- Cyanuric acid (stabilizer): 30 to 50 ppm
- Calcium hardness: 200 to 400 ppm
4. Shock and Chlorinate Your Pool Water
It’s important to shock and chlorinate your pool water prior to closing your pool. Superchlorination is a good practice to make sure bacteria and algae don’t linger in unsuspecting areas of the pool vessel. Attempt to shock the pool at least two days before the last days of your pool closing. If that is not an option, shock the pool water the night before.
5. Apply an Algaecide to Your Pool Water
After shocking the pool water, apply an algaecide. The algaecide must be applied after shocking, do not apply both shock and algaecide at the same time.
6. Backwash Your Pool Filter
Backwashing your pool filter, also called backwashing your pool, is an important step to keeping your pool water clean. Over the life of your pool, the filter medium becomes clogged with dirt, oil and other debris as water passes through in one direction. To keep your filter effective, send water backward through the filter to force out any debris.
Take a look at these backwashing process tips from pool professionals.
7. Prepare Your Pool Equipment and Adjust the Water
If your pool is in a climate that experiences freezing temperatures, you can run the risk of damaged or burst pipes. To prevent costly repairs to your pool plumbing in the winter, follow these tips to prepare your pool equipment for the harsh cold weather:
- Adjust your water level four to six inches below the skimmer (vinyl-lined) or tile line (plaster).
- Drain the pool lines. If your pool professional recommends antifreeze for your plumbing, use one made for pools, never automotive antifreeze.
- Drain your pump and filter (remove their drain plugs and keep them in the pump basket), blow out the plumbing lines, then seal each line at the pool end with a threaded or rubber freeze plug.
- Turn off all power breakers.
- Turn off all unused equipment to protect from snow and ice damage.
- If needed, remove unused hoses. Store hoses and Air Flow Meters in a safe, secure place.
If your pool is in an area that doesn’t have freezing temperatures in the winter, simply fill your pool water to a regular level and periodically check for evaporation. Also, remember to balance your pool chemistry at least once a month.
8. Install a Safety Cover
Installing a safety cover will protect your home and pool from potential accidents and winter debris. There are many different types of pool safety covers. To compare cover types, see our guide to swimming pool covers.
9. Lubricate the Essentials
One of the final steps to properly closing your pool for the winter is lubricating the essential pool equipment. Take some time to lubricate pump O-rings, backwash valve push-pull O-rings, and all threaded drain openings to prevent rusting. By lubricating these pieces now, you’ll ensure a secure, tight-sealing for next season’s pool opening.
10. Safely Store Accessories and Water Care Products
The last step in winterizing your pool is to store all pool accessories and water care products such as ladders, pool toys, robotic cleaners, skimmer baskets, wall fittings and solar blankets in a safe place. Additionally, we recommend separating and placing your water care products and chemicals in a dry, well-ventilated space out of reach of children and pets. CDC’s pool chemical safety guidance (2025) says to keep pool chemicals below 95°F, out of direct sunlight, in their original labeled containers and stored separately from each other. Our pool chemical safety guide covers the details.
Please remember, all pools are built differently, so consult your local pool professional for any questions about your specific pool equipment or climate in regards to proper storage.
What should you avoid when closing a pool?
A few common closing shortcuts can damage a pool’s surface or plumbing over the winter:
- Don’t leave chlorine or bromine tablets in a floater. A floater can drift against the wall and sit there for weeks, which can bleach or stain the surface.
- Don’t drop tablets straight into the pool. They sink, sit on the floor and can damage the finish.
- Protect each skimmer. After the lines are blown out, plug the skimmer line and add a skimmer freeze guard (a hollow tube that gives ice room to expand). Wrap the threads with thread seal tape so the guard seals and comes out easily in the spring. On a vinyl liner pool, a skimmer cover plate over the skimmer mouth lets you leave the water level up all winter, which saves water.
- Leave the main drain to your pool professional’s instructions. Most owners do not plug the main drain at the pool floor because it sits deep enough that it rarely freezes. Ask your pool builder or service company what your plumbing needs.
Once you’ve successfully completed these steps, your pool will be ready for the winter months ahead. Since the most rewarding and relaxing pool seasons start with a proper pool closing, you’ll thank your future self for going through the proper winterizing precautions.
Frequently asked questions
When should you close your pool for winter?
Close a pool once the water stays cool day and night and before the first hard freeze in your area. Start about a week before the closing date so there is time to balance the water, shock it and add algaecide in the right order.
Should you drain a pool to winterize it?
No. Lower the water below the skimmer (vinyl liner pools) or the tile line (plaster pools), or to the level your cover maker recommends, and keep the rest of the water in the pool. On a vinyl liner pool, a skimmer cover plate lets you leave the water level up.
What water chemistry should a pool have before closing?
The Oregon Health Authority’s pool water standards list ideal ranges of pH 7.2 to 7.6, total alkalinity 60 to 180 ppm, calcium hardness 200 to 400 ppm and cyanuric acid 30 to 50 ppm. Follow your pool builder’s targets if they differ for your surface.
Should you shock a pool before closing it?
Yes. Shock the pool at least two days before the final closing day (or the night before if that is not possible), then add algaecide after the shock, never at the same time.
Where should you store pool chemicals over the winter?
CDC’s 2025 pool chemical safety guidance says to store pool chemicals below 95°F, out of direct sunlight, dry, in their original labeled containers and separately from each other. Keep the storage area secured from children and pets.
Can you close a pool yourself?
Yes, many owners close their own pools by following the steps above. In a climate with hard freezes, or if you are unsure about your plumbing, ask a pool professional to blow out and plug the lines.
Have a spa to get you through the winter months? To see how a Clear Comfort hydroxyl-based AOP system works alongside a low chlorine residual in a home spa or pool, visit our residential page.
Louie Warco
Customer Success Manager
