When Should I Change The Water In My Inflatable Hot Tub?

In this article, we’re looking at how to know when it’s time to change the water in your inflatable hot tub. When you think of enjoying your inflatable hot tub, certain images probably come to mind.  Slipping into the hot bubbling water and leaning back for a deeply satisfying massage.  Maybe an afternoon of family fun time.  Perhaps it’s stretching out in your inflatable spa and enjoying a lazy soak in the evening after a hard, stressful day.

Whatever it is, each image is sure to include crystal clear water. And this is certainly a key aspect of enjoying your inflatable hot tub.

We have already seen in our article Your Guide To Inflatable Hot Tub Chemicals about how to keep the water sparkly clean with the right use of inflatable hot tub chemicals.

But not only do you have to treat the water, to keep it clean and hygienic, you also need to change the water regularly. It’s not enough to wait until it looks, feels or smells like it could do with a change. That’s because by the time it reaches that stage, you have probably been using your hot tub way past it’s change-the-water date! This in itself can cause some skin and health problems.

But knowing when to change the water can sometimes be a puzzle.  Help is at hand here with our simple guide in answer to the often-asked question: How often should I change the water in my inflatable hot tub?

How To Empty Your Inflatable Hot Tub

Whichever inflatable hot tub you own, changing the water is easy enough.  The precise procedure differs slightly, depending on the model you own, so be sure to check your Owner’s Manual.

These, though, are the basic steps that apply to every inflatable hot tub.

  • Switch off and unplug the electricity supply to the hot tub.
  • Then attach a garden hose to the drainage valve, using a hose adaptor if required. 
  • Place the other end of the hose into an area where the old water can drain safely away.  This needs to be away from flowers, plants, and grass, as the chemicals in the hot tub water can harm them.
  • Next, undo the drainage valve inside the inflatable hot tub and the water will empty out.
  • Give the inside of the hot tub a good clean, including the underside of the lid.
  • Re-fill the hot tub with fresh water, pop the lid back on, and re-heat the water.

But how often, then, should you change the water in your inflatable hot tub??

How Often To Change The Water In Your Portable Spa

First off, you don’t want to or need to change the water too frequently.  This will send your water – and your heating – bills through the roof (think of all that hot water pouring away, how much it cost to heat it, and how much it will cost to heat the fresh water!)

On the other hand, you also don’t want to leave the water in your inflatable hot tub for too long, as you will end up soaking in hot water that is dirty and potentially unhygienic and unsafe. There is an article you might want to read over on the Good Housekeeping website which deals with the potential problems of using a hot tub when the water is not clean, which you can read here (opens in a new link).

Getting the balance right between changing your water too-often and not-enough is a bit like trying to balance a seesaw.

Fortunately, we have a general rule you can use, to help work out when to change the water in your inflatable hot tub. It goes like this:

Take the number of gallons your inflatable hot tub holds, which you’ll find in your owner’s manual or on each of our reviews. Divide this number by 3. Then take that number and divide it by the number of people who regularly use the hot tub every day. The number you end up with shows you how often you should change the water.


Let’s take the Lay Z Spa Paris as an example.

The Lay Z Spa Paris holds 250 gallons of water. Divide that by 3, and you get 84 (rounded up from 83.33).  If 2 people use the hot tub regularly every day, then 84 divided by 2 equals 42.  This means you need to change the water every 42 days, which is once every 6 weeks.

This is only a guide of course, and you might find there are times when you need to change the water irrespective of that calculation.

Signs It Is Time To Change The Water In Your Inflatable Hot Tub

These are some of the most important signs to look out for.  They tell you that you need to change the water in your inflatable hot tub as soon as possible.

Cloudy Water

When the water in your hot tub starts to look cloudy, the first thing you need to do is shock it.  See our helpful guide on How To Shock Your Inflatable Hot Tub for everything you need to know about how to do this.

If shocking your hot tub water doesn’t work, however, then change the water straight away.


The first thing you need to do if the water looks foamy is to use a hot tub de-foamer, such as SpaGuard Spa Anti Foam. This usually clears up the problem and you can carry out using your hot tub freely.

If the foam returns soon after you use the de-foamer, however, then it is time to empty out the water, clean your hot tub, and re-fill it with fresh water.

Smelly Water

The moment you take the cover of your inflatable hot tub, and notice that the water smells: change the water. You might find some sites telling you to add chemicals or try some tricks.  But the truth is, you really need to drain the tub and fill it with fresh, clean, odor-free water.


Keep an eye on when you last changed the water in your portable spa. If it has been two months or longer, then it is definitely time to change it.  No matter how fresh it seems and how much you have used it.

Remember: there can be bacteria lurking in the water, so it is better to be safe than sorry.


Many people are surprised to learn that peeing in an inflatable hot tub can be extremely dangerous! That’s because pee contains a chemical called urea. The urea in the pee mixes with the sanitizer in the hot tub water to create a hazardous nitrogen compound called chloramine.

Now chloramine can cause some nasty problems which come from exposure to the chemical on your skin and by breathing in the steam from your hot tub water. These health hazards include:

  • sore throats
  • breathing difficulties
  • coughs
  • wheezing
  • asthma
  • skin conditions
  • susceptibility to bacterial infections

So if you know, or suspect, that someone has peed in your inflatable hot tub, you should first shock the water. If there is still a strong smell of chemicals after you’ve shocked it – say a day or so after – then there are probably traces of urine left on the hot tub’s vinyl. So you’re going to have to empty your hot tub and give it a good clean.

We have a useful guide on the dangers of someone peeing in your inflatable hot tub, and what you can do about it, here: Why You Mustn’t Pee In Your Inflatable Hot Tub.

Keeping Your Inflatable Hot Tub Clean

When you change the water in your inflatable hot tub, it is the perfect time to carry out a couple of other simple cleaning tasks.

After you empty the hot tub, give the water filter a good clean. Give the hot tub itself a good clean as well.  We have written a simple guide which covers both of these: How To Clean Your Inflatable Hot Tub.

By carrying out these two tasks, you can relax in the knowledge that everything about your inflatable hot tub is perfectly clean, so the water you add to refill it, will be sparkly clean and fresh from the start. Thanks for reading!

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