How to Winterize Your Pool the Right Way—and Avoid Costly Repairs

Once temperatures drop below freezing, it's essential to prepare your pool for winter. Failing to do so can lead to long-term damage; however, keep in mind that there's a difference between closing a pool and winterizing it. The former involves simply turning things off and adding a cover, while the latter requires more proactive measures—ultimately protecting your pool from the negative effects of freezing and thawing.

Not sure where to start? Below, our experts break down the first steps, how to choose the right pool cover, what you need to know about water chemistry, and other tips and tricks to successfully protect your pool from the cold.

How to Clean Before Winter Arrives

Before you begin the winterizing process, it’s important to perform a deep clean. Remove any leaves that have sunk to the bottom of the pool—this can cause staining—and brush away any pollen or dust. 

The goal is simply to remove anything that can rot and mess up the water chemistry. "First, skim everything off the surface: leaves, bugs, and anything floating,” says John Uhle, founding partner and product expert at Discount Salt Pool. “Once the surface is clear, vacuum the floor to pick up dirt, sand, and any leaf scraps. Pool walls and steps tend to build up a light slime that can mess with water chemistry.” 

Water Chemistry

The water needs to remain balanced throughout the winter season, even if no one is using the pool.

“Balanced water chemistry in winter [leads to] a healthy, clean pool in spring,” Uhle says. “Shocking a pool is absolutely necessary before winter, because pools are very susceptible to bacteria growth [during this time] due to no circulation, no sunlight, and no filtration."

Scott Rajeski, president and CEO for Latham, The Pool Company, suggests following these steps to prepare your pool water for winter: 

1. Adjust your pool’s pH between 7.2 and 7.8 to prevent staining and scaling. 
2. Shock the pool water following the normal product instructions. Pool shock refers to various chemical products that are designed to raise the levels of free chlorine in your swimming pool, so the chlorine is available to kill algae, bacteria, and other contaminants. 
3. Run the filter for 24 to 48 hours.
4. Vacuum the pool thoroughly (if you haven’t already) to remove any debris. 
5. Add an algaecide to prevent algae from forming before the water freezes. 

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Removing Accessories

Take out any accessories—including ladders, skimmers, diving boards, basketball hoops, and slides—and store them in a protected place for the season. “Once everything has been taken out of the pool, cover it with a seasonal safety cover that’s designed to withstand water, weather, and pool chemicals," says Rajeski.

Pool Cover Considerations

Homeowners are often torn between a standard winter cover and a safety cover. “A winter cover keeps leaves and debris out, but a safety cover does that and protects what matters most—your family,” says Rajeski. “Designed to support thousands of pounds (roughly the weight of a small SUV), safety covers anchor security into the pool deck, creating a clean, taut look that's built to last—even through the harshest winter conditions.” 

Consider both cost and function when deciding what works best. “In warmer climates, solar covers can extend the swim season for a month or more, but they're hard to upkeep,” says Brock Falk, pool care field manager at Shasta Pools. “They tend to fall apart in the sun within a few years, and they're tough to put on or take off when you only want to use the pool for a day.” 

Fixed covers require anchors to be placed all around the pool. “You need to decide if you want an open, mesh, or solid cover,” Falk adds. “No matter what you choose, you'll still need to balance the chemicals. Keep that in mind for access when you have a tab floater. Solid covers also need a cover pump to pump water off during winter rain events.”

Water Levels

Only a few types of pools need to be completely drained during winter. “A completely empty pool can also crack or pop out of the ground because of pressure from groundwater,” Rajeski says. 

Many pools tolerate cold temperatures better when partially filled with water as a buffer. “We all know when water freezes, it expands,” Meece says. “That expansion in your pool can cause structural damage to materials like concrete, plaster, and tiles. Lower the water level to approximately 6 inches below the lowest plumbing feature—usually a jet or a skimmer—to prevent this.”

However, some pool covers might recommend otherwise. “If an automatic cover is being used, be sure to follow the manufacturer’s instructions regarding water level,” Rajeski notes.

How to Protect Your Pool Equipment

“Be sure to turn off the power to all of your pool’s electrical equipment and drain the pump, filter, heater, and other equipment of all water to avoid any freeze damage,” Rajeski says. “Store equipment to prevent damage, and follow the manufacturer's instructions for lubrication and proper covering. Be sure that all power to the support equipment is off. Remove fuses or turn the circuit breakers to off.” 

What to Maintain Through the Winter Months

Experts recommend maintaining and keeping a careful eye on the following pool features:

• All the basics: Chemicals still need to be balanced, baskets emptied, surfaces brushed, and equipment inspected, Falk says.
• Check the cover: Rajeski recommends checking your cover often. Make sure the straps and springs stay tight, and look for any signs of wear. 
• Remove snow and ice buildup: Use a broom or leaf blower to get snow off the cover. Make sure you don’t use anything sharp.
• Ensure your freeze-protection system is working: This includes checking that the equipment turns on when temperatures drop, Rajeski says.

When to Call a Professional

Winterizing isn’t difficult because it’s heavy work—but you do need to get every little step exactly right, or you risk dealing with big issues and expenses.

“The equipment draining, the plugs, and the chemistry are the three most complex parts of winterizing a pool,” Uhle says. “Having a pro do this job is honestly the best decision, because they have the right compressor setup to blow out the lines completely, preventing water from freezing and cracking the pipes.”

Pools are a major investment, and minor issues can escalate into major problems that cost tens of thousands of dollars. “Having a professional close your pool means they can spot early warning signs of leaks or equipment problems,” Meece says. “Every pool has different closing needs, depending on type and features. A pro can take these into account."