Using an Inground Pool in Winter

An uncovered pool spa combo is surrounded by snow. More snow is falling.

Memorial Day, Fourth of July, Labor Day—all great days for playing in your pool—but what about Thanksgiving, Valentine’s Day, or even New Year’s Eve? Most pools (except those used in far southern regions) can’t be used comfortably year-round without a supplemental heat source.

Depending on your pool, location, and the lengths you’re willing to go to, it is possible to enjoy your pool year-round.

But before you cancel your pool closing plans, learn more about what it takes to prep your pool for winter use.

Do Pools Freeze in the Winter?

Yes, they can. A pool that has not been winterized (shocked, drained, and prepped for winter) and is not being kept at the appropriate temperatures will freeze within a few days when temperatures dip below freezing. The freezing point of chlorinated water is the same as that of tap water, 32°F. Saltwater pools can typically withstand a few degrees cooler (around 28°F).

Do You Have to Close Your Pool in the Winter?

No, but most homeowners in cold climates choose to close outdoor pools for the winter for a variety of reasons including:

  • Design limitations: A pool that is to be used all winter must be designed to function during average winter low temperatures. This means choosing a heater that is suitable for low temperatures and that is powerful enough to keep the pool warm enough to prevent freezing and promote use. Other considerations include pool plumbing insulation and pool deck design. (The deck will need to be shoveled—it’s not recommended to use sidewalk salt on a pool deck.)
  • Maintenance concerns: Just like in summer, it’s critical to make sure the pool pump and heater run efficiently all winter to prevent freezing. The freeze and thaw cycle can damage pool equipment beyond repair, necessitating replacement. Heavy precipitation may disrupt your pool’s chemistry—it will need to be tested and balanced regularly. Further, the pool should be regularly inspected and cleaned.
  • The reality of winter use: Homeowners who choose to keep their pools open all winter typically do so for two reasons: to swim and to enjoy the pool for aesthetic reasons. If you don’t mind the look of a winter pool cover and have no intention of going for a dip in December, closing your pool is the best option.

Related content: The Best Way to Heat a Pool

What Temperature Do I Need to Heat a Pool to in Winter?

For comfortable swimming temperatures, your pool’s temperature should be kept between 78°F and 82°F. For each additional degree, homeowners can plan to add 10-30% to their total energy consumption.

Not sure about keeping your pool open, but looking for a way to get outdoors or enjoy a warm soak? Consider installing a hot tub or spa. It’s usually less effort on the part of property owners and more energy efficient to maintain a hot tub (designed for all-season use) in winter than to retrofit and care for an existing inground pool in winter.

Heating an Outdoor Pool in Winter

Heating your pool in winter is one of the most important steps to enjoying your pool and preventing damage. The pool and its equipment must be kept from freezing. Not only will a freeze render the pool unusable for the season, but it can cause catastrophic damage to the system.

If your pool is already equipped with winter-ready heating equipment, be sure it is set to the appropriate temperature and in good working order. If you do not have an appropriate pool heater, There are a variety of options for you to consider. These include gas heaters, solar heaters, and air-source or water-source heat pumps. Additionally, a solar blanket can be used to prevent evaporation and heat loss.

Ultimately, the best option for your pool will depend on a variety of factors including your location and predicted weather patterns as well as the level of investment you’re willing to make.

Is a Pool Freeze Protection Sensor Worth Installing?

Yes, it is. If your pool is not already equipped with a freeze protection sensor, we recommend installing one. Even if you don’t intend to leave your pool open all winter, these pieces of equipment can be a lifesaver in the shoulder seasons.

Pre-programmed to turn on the pool pump when the air temperature drops to a specified degree, the freeze protection sensor helps to prevent unforeseen damage to a pool. This type of sensor can also alert you to a heater failure—potentially saving you thousands of dollars in damage.

Winter Pool Safety

Should you keep your pool open in the winter, you’ll also need to take additional safety precautions. These include:

  • Ensuring and maintaining a safe path to and from the pool.
  • Heating the pool to a safe temperature. Remember, hypothermia can occur in as little as 15-20 minutes.
  • Test and balance pool chemistry.
  • Vacuum and skim the pool as necessary.
  • Maintain safety equipment (ladders and stairs, life rings, etc.)
  • Engage in safe swimming behavior (swim with a buddy, swim sober, monitor children closely in the pool, and more.)
  • Install a backup power supply. If the power is out for an extended period, your pool may freeze. Consider a generator for extra protection.

Related content: Why You Should Start Your Kids Swimming at a Young Age

Enjoy an "Endless" Summer with Help from ASP—America’s Swimming Pool Company

Whether a year-round pool or the addition of a hot tub is in the cards for your property, rely on our teams of local pool experts to install, repair, maintain, or upgrade your pool and spa systems. We’re licensed, insured, and ready to help you enjoy your pool in every season—even if that’s just your view from the kitchen window! Request service online or call (866) 253-0455 to learn more.