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How To Winterize Your Swimming Pool


The following are generalized instructions on how to properly close an In-ground swimming pool. Please note that all pools are somewhat different and your pool may need specific care not mentioned here. If you have any doubts about how to properly close your particular pool contact a local pool professional.

It’s that time of the year again -- in some parts of the country, the weather is becoming too cool to enjoy the pool, and even though it's not quite Labor Day, it's time to think about winterizing your pool. Even if you are a lucky pool owner who lives in a warmer climate, you still have to take a few steps to winterize your pool. In the Northeast and Midwest there are a fair number of steps to follow, whereas in California and other warm-weather environments, winterizing mainly consists of reducing the filtration time from 12 to six hours. However, no matter where you live, if winterizing is not done properly, it can result in costly problems such as broken pool equipment.

Professional pool companies charge an average of $200-400 dollars to winterize, but they also provide peace of mind all winter. Pool service companies ensure their winterization work, and they prioritize customers who get winterization services, so if there are any issues in the spring you will be first on their schedule when they make service calls.

If you are planning on tackling winterization yourself, it is very important to take the time to ensure it is done properly. For example, when water freezes it expands to nine percent of its volume, so water stuck inside a pool pump could freeze, expand, and break your pump. Damage like that could cost upwards of $400. Additionally, another common problem resulting from improper winterization is the rear header of a heater. This is because it captures water and is the farthest away from a heat source. A new header costs nearly the same amount you would spend on professional winterization, so it’s important to either hire a professional, or carefully follow the tips below.

Steps to close down the pool in Northeast and Midwest regions:

  1. Blow the lines – Use an air tank and force out all the water from the lines.
  2. Plug the lines – Use different size plugs depending on the size of the pipes to prevent water from getting back in. After blowing the lines of water, seal the pipes with the appropriate size plugs to prevent water from entering.
  3. Add chemicals – An important step that should not be overlooked is to add winterization chemicals at the first sign of winterization. Then, periodically add additional winterization chemicals (not chlorine specific) throughout winter. It is unlikely for algae to grow during the winter, however, these chemicals help slow the process in the spring when the water warms back up.
  4. Cover the pool – Mesh covers do not prevent water (rain/snow) from getting in the pool but they do prevent debris from getting in. Solid covers require a pump on top of the cover to pump water off the cover.

In regions where periodic freezing occurs, such as Northern Texas, Georgia, and Northern California, you must take steps to winterize, even if the pool is not fully closed. The main concern in these areas is that water could freeze in the pipes if the pump is not running. Freeze protection is a feature that turns on the pump when air temperatures get near the freezing point, usually activating at around 38 degrees Fahrenheit air temperature. Special note here: all Zodiac® and Jandy® controllers have freeze protection built-in. If you do not have a control with freeze protection, it is important to watch the weather report and turn on the pump when freezing temperatures are imminent.

Special Tips:

  1. Do not forget the winterization chemicals! This is a common mistake since algae is unlikely to grow in the winter, but you are protecting yourself for springtime, when algae can grow quickly.
  2. Let air run through your heater, and do not wrap it. In colder regions, cover the top of the heater with plywood, not with plastic wrap or any plastic material. Keep the sides of the heater exposed so moisture does not get trapped inside which can cause rusting of heater components.
  3. Do not use anti-freeze in the pool.
  4. In general it is not necessary to lower the pool water level. For pools with a tile line it is better to leave the water level at the tile line where it is easier to clean.
  5. As soon as the temperature starts to warm, perform a chemical test. Add the spring chemicals to ensure the water will be clearer when you open the pool fully. Do not wait until you are ready to open the pool to check the chemical levels.
  6. If you do not have freeze protection, in areas where the pool is left open, watch the weather and turn on the pump if it is nearing freezing temperatures.

It is important to winterize properly. Taking time to make sure it is done right can save you money and frustration. Not to mention impacting the precious time you have to enjoy your swimming pool. SO, if you don’t have the time or know-how to do it yourself, call in a professional and have it done for you.

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Includes all the latest information, tips, and expert advice from Zodiac Pool Systems, Inc. on owning the healthiest, safest, most enjoyable pool possible.


Zodiac is a leading global manufacturer of differentiated pool and spa products. With our rich heritage of innovation excellence, we develop some of the world's leading products that afford our customers a better life.


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