How To Winterize A Hot Tub (The Right Way)



If you live in an area of the world with four seasons, you should consider winterizing your hot tub during the cold months of the year.

Similar to the winterization process for pools, it protects the tub from taking on unnecessary damage due to non-use.

However, with a higher water temperature in hot tubs, many spa owners choose to keep their tub open so they can use it over the winter months. 

What Are The Benefits To Winterizing?

There are serious benefits to winterizing that you should consider if you won’t be using your tub much when the weather turns cold.

  • It protects the shell. Winterizing requires draining the water from the tub. By doing this, you avoid any damage to the hot tub’s shell. When there’s water in the tub, and cold weather freezes it, the water turns to ice and expands. This expansion can lead to cracks and fractures in the shell, which will either require extensive repairs, or a full tub replacement.
  • It saves your plumbing. When winterizing, the pipes need to be blown out. Blowing out the pipes refers to removing water from inside of them. This process protects the pipes from cracking, as frozen water will expand if left in the pipe. Hot tubs use both hard PVC pipes and softer, flexible PVC pipes. Both are at risk of being compromised if the outdoor air drops to an ungodly temperature.
  • It protects your equipment. When you close down the tub you’ll remove the cartridge filter and store it indoors for the winter. You’ll also drain any water from inside the pump and heater. Again, this is to keep ice from forming inside these vital components and causing extensive damage.
  • Less upkeep. If you won’t be using your tub in the winter, why keep it open? You’ll have to keep running it and cleaning it so that it doesn’t develop any problems. It’s less work to close it down and reopen it rather than doing weekly maintenance in the freezing cold.
  • Saves you time and money. By winterizing the tub, you’ll save time on testing the water, and money on all the chemicals that are needed to keep the tub in a neutral state. Not to mention you won’t have to clean or drain the tub if it’s winterized for more than 3 months.

When Should You Winterize A Hot Tub?

Winterizing depends on three things: 

  • if it’s an indoor or outdoor tub
  • how cold it gets in your neck of the woods
  • if you plan on using the tub during the winter months.

Obviously, if you have an indoor tub, you don’t have to winterize it. A temperature-controlled room will allow you to use the tub year round without any repercussions from cold weather.

If you live somewhere where the winters are downright dreadful, you may want to winterize the tub for the beneficial reasons outlined above. 

However, if you’ll be using your tub all year long, even in the coldest of winters, as long as you keep it maintained, and run it like you would any other time of year, there shouldn’t be any problems concerning damage to the tub or equipment. This is because the water won’t freeze and wreak havoc through the filtration system.

Keep in mind though, if you decide to run the tub in the winter, the colder weather will cause the water temperature to decline faster, and you’ll have to run the system and heater more often. This can cause a spike in your monthly bills. 

Additionally, if something goes wrong with any equipment, fixing it can be a pain in the middle of winter.

How To Winterize A Hot Tub Or Spa

Let’s get to it. Winterizing your spa is a labor intensive process, but with the proper guidance (courtesy of Poolonomics), you should have no problem closing the tub by yourself. 

What you’ll need for winterizing:

  • Submersible pump (optional)
  • Garden hose with nozzle
  • Shop-VAC
  • Antifreeze
  • Funnel
  • Filter cleaning product
  • A large bucket
  • Hot tub cleaner
  • Hot tub cover cleaner
  • Soft cloths and sponges

Step 1. Stop And Let It Drop

The first thing you need to do is nothing. Seriously.

Let the chemical levels in the tub drop (especially the sanitizing chemicals), as disposing of this water can be problematic otherwise. Let things sit for a few days, test it, and once the chlorine or bromine has dropped to zero, you can begin the process.

In the meantime, cut off all power to the tub. Some models might only require you unplug it from the power outlet, but your tub may require you completely shut off a breaker as well.

Make sure there is absolutely no power getting to your tub or it’s filtration system. Water and electricity don’t mix, especially when winterizing your tub.

Step 2. Drain The Tub

Draining is fairly straightforward, and you can either use the drain plug at the base of the tub (slow drain), or use a submersible pump (fast drain).

If using the drain plug, remove it and attach a garden hose to the port so it can move the water to a safe place away from plants and wildlife.

If using a submersible pump, attach the garden hose to the pump and place the unit inside the tub. Make sure the pump doesn’t run if there’s no water in the tub, as this can damage the motor.

Whichever draining method you choose, ensure the hose is emptying somewhere safe. A sewer or storm drain are the usual end points, but always consult your city’s ordinances when it comes to the disposal of waste water.

Step 3. Drain The Air Blower

With the tub empty, you need to start removing water from the lines in the filtration system.

First up is the air blower. Not all hot tubs have one, but if yours does, here’s how to drain it:

  1. Turn off the heater. Ensure the power switch is in the OFF position. The heater should never be on when there’s no water in the tub.
  2. Put the hot tub cover on.
  3. Either turn the breaker on, or plug in the tub. 
  4. Turn on the tub. This will “blow out” the remaining water in the air blower line. Run it for 30 seconds.
  5. Turn off the hot tub.
  6. Unplug the tub once again, or turn off the breaker.
  7. Take the cover off the tub and move onto Step 4.

Step 4. Loosen Unions

Remove the side panelling on your tub to expose the pump and heater. This equipment will be attached to the filtration system’s pipes with union joints. 

Unscrew these joints at both the pump and filter point, letting the water drain out. Doing this saves the pipes and equipment from catastrophic damage, as frozen water can crack and destroy these components.

Some pumps also come equipped with a drain plug. If yours does, remove the plug to get every last drop of water out of the pump.

Step 5. Winterize The Filters

The majority of hot tubs use cartridge filters made of delicate polyester or paper. 

When winterizing, you’ll need to remove them and store them indoors.

However, you should first clean the cartridge so it doesn’t sit for months with various contaminants on it. This also ensures it’s ready for immediate use when you reopen the tub.

Cleaning them could mean a simple hosing down of the cartridge using a garden hose with a nozzle attached. If there’s a lot of debris on it, you should give it a chemical soak.

You can do this by mixing a filter cleaning product with water in a large bucket, and leaving the cartridge immersed in it for 24 hours. Rinse it well and dry it off.

If, when you remove the cartridge, it’s falling apart, dispose of it and use a new one when you reopen the tub.

It’s also important to remove any water that is left in the filter well. This can be removed using a Shop-Vac or towels.

Step 6. Service The Lines

This step requires you to blow out the plumbing lines, similar to what you did with the air blower in Step 3.

If there’s any water left inside the tub’s system lines, freezing will cause damage and cracks. The most susceptible are the flexible PVC lines which run on the underside of the shell. Ice can easily crack this material and you’ll then have a leak that needs repairing.

Grab the Shop-Vac and set it to “blow”. Insert the Shop-Vac’s hose into every hole you can find – the drains, unions, jets, and skimmer/filter cavity.

By blowing each spot for 15 seconds, you’ll push out any water from the lines, directing it into the tub.

It’s recommended to do this step twice, to ensure you’ve effectively dried out the lines.

Step 7. Clean The Shell

After blowing out the lines, water may have settled in the tub. Drain any remaining water and then move on to cleaning the shell. 

The downside of cleaning the tub is that it takes some time. But the upside is that it’s easy to clean an empty tub, and it will protect the finish from any chemical residue that might have been left behind.

You can clean your tub by pairing a hot tub cleaning product with soft items like sponges and cloths. Of note, make sure these cleaning tools are non-abrasive, so they don’t scratch the shell. The waterline may have a build up of scum on it that requires soaking with a cleaner for easier removal.

Additionally, you can clean the tub by using household items like vinegar or baking soda, if you don’t want to pay for a hot tub product or prefer natural chemicals.

Rinse the shell so there is no residue left and dry the tub using a towel. Replace the drain plug at the base of the tub if you used this draining method.

Step 8. Add The Antifreeze

Antifreeze will keep the lines from freezing over the duration of the winter months.

Using a product such as Engine Ice gives you a biodegradable antifreeze that’s non-toxic, free of phosphates, and won’t damage any aluminum or metals.

Go around the hot tub with the antifreeze and a funnel, pouring it into any lines where water enters or exits the tub. This will keep the pipes from taking on any damage that can be caused by the stresses of cold weather.

Step 9. Clean And Attach The Cover

Cleaning the hot tub cover needs to be done thoroughly. If you clean the cover regularly, it should already be in good shape. 

But with the tub sitting in the sun for many months, you’ll need a cover cleaner that also protects it from UV rays. 

Make sure the cover is cleaned well, protected, and then dried. You can let it air dry, or dry it with a towel. The smallest amount of moisture can cause a mold outbreak over the winter months, and then you’ll have a different problem to deal with.

Place the dry cover on top of the spa and secure it to the structure. If your cover has locks, use them. Not only will it keep debris out, but it will also keep people or wildlife from crawling into the tub over the winter.

You should also invest in wind straps if the cover doesn’t have them. This further secures the cover from blowing away in inclement weather.

Winter Is Coming!

Seasonal changes are inevitable, and if you live somewhere where the temperature seriously drops, you should consider winterizing your hot tub if you don’t plan on using it year round.

The process takes some time, but your tub, equipment, and bank account, will all thank you for protecting them from winter’s wrath.

Categories: Hot Tub Care, Hot Tub Maintenance