How to Clean a Hot Tub That Has Been Sitting – Cleaning Made Easy!

Michael Keenan


Hot Tub Maintenance

The thought of cleaning out an old hot tub may seem overwhelming – especially if it has been sitting around for months. But no matter how daunting the task may seem, all it takes is time and some elbow grease to make your spa usable once again.

In this article I’ll go over tips on how to clean out a stale hot tub properly – from checking if the filter is working, draining the water, purging debris and particles with specialized chemicals, shocking it with sanitizer, and refilling with balanced water chemistry.

Plus learn why it’s important to shock before using your spa again.

“Is it even worth the effort?” you may wonder. However, if you put in the work, you will be able to enjoy the hot tub for months and will be grateful that you did not let the spa go to waste.

If cleaning out a sitting hot tub has been weighing on you, the following are the steps you can take to restart that glorious tub.

how to clean a hot tub that has been sitting

Quick Answer:

It’s worth it to clean a hot tub that has been sitting for a while! This article provides easy-to-follow steps for draining the old water, cleaning out the filter, purging with specialized chemicals, and refilling with safe new water.

With just a little effort, you can have your hot tub ready to enjoy again. So dedicate a weekend and make sure you can use that hot tub again this season!

First Check If the Spa Filter Is Working

The filter is one of the most important aspects of a hot tub. Only if the filter is functional will the hot tub be clean. A hot tub that has been sitting will likely have a clogged filter. White flakes (or biofilm) are another common problem.

So restarting a hot tub would entail cleaning the filter out first. To clean your hot tub filter, you will need to soak it overnight, preferably with a spa cleaner. After having soaked it overnight (or perhaps even longer) you can use clean water to rinse it out.

To be sure that the filter has been cleaned out thoroughly, you may want to let it dry completely before re-inserting it into the tub. However, even before you remove the filter to clean it you will need to check if it is working at all.

So drain the hot tub if it has water (as the water will likely be dirty and it will clog the filter if it has not already) then add fresh water till the filter is just submerged.

Then using the spa controls turn on the hot tub. Toggle the various controls to see if everything looks functional.

Most importantly, check if there is water leaking from the tub. If everything looks fine, you can remove the filter and clean it. If required, replace the filter cartridge.

Draining the Hot Tub

Draining the hot tub is important if it has been sitting for a while. Stagnant water will collect dust, and algae and can also become home to breeding insects. There should be a drainage hose or port which will allow you to purge the hot tub.

Sometimes you can get away with a quick clean without draining your hot tub. See my guide on how easy it is. And don’t forget to clean the hot tub cover!

Draining the spa can take some time, depending on how much water has collected. You can also submerge a pump into the spa to drain the water, though ensure that all power outlets have been turned off.

Once the tub has been drained, if you can still see the residue of mud or other impurities, use a garden hose or power washer to rinse off the surface of the hot tub. If you notice that grease or mud has accumulated on the spa jets, spray it off with a hose.

You have to ensure that equipment like the pump, heater, (electrics), etc. do not come in contact with the water. You can also use a soft cloth to clean out the spa shell and other components.

If the dirt is difficult to remove, try using white vinegar to dislodge it so it comes off easily with water afterward.

dirty hot tub water

Purging the Hot Tub

Simply using water and vinegar is not enough to clean the hot tub completely. If it has been sitting for a while, then there is a possibility that the piping and other components of the tub are also coated with minerals, biofilm (white water mold), and other particles that can destroy the tub and equipment.

To purge the hot tub, you will need to use some specialized chemical that can dislodge the gunk even from the most difficult corners. Refill the tub and add the chemical according to the label instructions.

Make sure that the pump is running so that the chemical spreads evenly and does a thorough job of cleaning the whole tub, including the insides of the pipes.

After the pump has run for some time you will start noticing brown particles rising to the surface of the water. These are the impurities that you could not have gotten rid of by simply spraying the surface of the tub with a garden hose.

Find out how I get sand out of my hot tub here! Some useful tips.

Drain Again

Once you are satisfied that the chemical has dislodged all the possible impurities from the tub, you will need to drain the tub again (unless you want to sit in this bath of dirt, chemicals, and water!).

As the level of the water drops while you are draining it, be ready with a clean cloth so you can keep wiping down the rims of the tub.

Once the tub has been drained completely, you can use a sponge or some kind of dry vacuum technology to blow the tub completely dry.

If there are still some particles remaining on the surface of the tub, bring out your trusty soft cloth again and wipe down the surface. You can even use vinegar again for good measure.

cleaning sponge and gloves

Refill for Good!

Once the tub looks squeaky clean, it is time to refill the tub again! Fill it with fresh water until the point you desire, then use a home testing kit to test the chemistry of the water.

Depending on how the water tests, add the required chemicals that will appropriately balance the pH, alkalinity, and calcium levels in the water. Here you can choose the type of hot tub sanitizer you’ll use – remember there are alternatives to chlorine! This is an important step, especially if a lot of different people will be using the tub.

Now might be a good time to consider the benefits of a hot tub saltwater system. See my guide on that and see why so many people are converting their spas.

You don’t want to clean the tub only to fall sick from the freshwater you have refilled into it. Once you have balanced the water chemistry, you will also need to shock the spa water so you can be sure that it is fit to be used for a long time without needing refilling.

Several stores will carry spa shock so you can pick out one based on your budget and requirements. Once you have shocked the water, it would be advisable to wait at least a day before you use the tub so that all the chemicals can dissolve and the water is safe to use.

Then voila, the tub is ready!

dirty water sitting in a spa


What tools and supplies are needed to clean a hot tub that has been sitting?

To clean a hot tub that has been sitting, you will need a strong cleaner like chlorine bleach, bromine tablets, an algae brush, and test strips to check the water’s pH level.

Are there any special considerations when cleaning a hot tub that has been sitting for an extended period of time?

When cleaning a hot tub that has been sitting for an extended period it is important to pay extra attention to areas where debris may have accumulated such as filters and jets. Additionally, it is recommended to replace the water in the hot tub after deep cleaning to ensure any remaining contaminants are eliminated.

Is it possible to prevent the need for deep-cleaning a hot tub that has been sitting by regularly maintaining it?

Yes, regularly maintaining and cleaning your hot tub can help prevent the need for deep cleaning and ensure your spa remains in an optimal condition at all times!

Final Thoughts

The process of cleaning a hot tub that has been sitting, especially if the water has become a breeding ground for insects, may not be the most pleasant activity. However, what you get at the end of this process is completely worth it.

To get your hot tub up and running again, you need to check if the filter is working, drain the hot tub, purge it with specialized chemicals, shock it after refilling, and wait a while before use.

You can have your kids play in the tub or even invite friends over for a hot tub and BBQ party. So dedicate a weekend to this chore and clean out the tub, it will be the best use of your time!

michael keenan author

Author - Michael Keenan

I'm Michael Keenan the owner and creator of the Outdoor Care Guide. I'm a trained horticulturist with over 30 years of experience in pool care, plant care, and landscape care! Seemed like a good idea to share - I think I can make your life easier and save you some time and money!