How Often Should You Change Hot Tub Water?

Hot tubs are a great way to relax and unwind, but they must be maintained properly to ensure a safe and enjoyable experience.

One of the most crucial aspects of hot tub maintenance is changing the water. But how often should you change the water in your hot tub?

Before buying a new hot tub, one of the first questions many people ask is, “How often should you change hot tub water?” because it seems that many people seem to think you need to empty and refill it every time you use it, just like taking a bath, which is completely wrong.

In this article, we’ll explore the factors determining how often you should change your hot tub water and provide some guidelines to help you keep your hot tub clean and safe for use.

How often to change hot tub water

Most manufacturers recommend changing your hot tub water regularly, perhaps every three months.

This does depend on how well you maintain the water quality, how often it is used and the number of bathers who use it. The more it is used, the more often the hot tub water should be changed.

Hopefully, the rest of this article will help you decide how often to change your hot tub water.

When to change your hot tub water?

Ideally, you shouldn’t wait until you can actually see that your hot tub water is dirty. If the water in your hot tub looks dirty or smells bad, then that may mean you have been using it when the water was past its best.

There are several different reasons you may need to change your hot tub’s water:

Frequency calculation

Some hot tub owners use a rule-of-thumb calculation to determine how often to change the water. You divide the total gallons your hot tub holds by the average number of people/frequency that use it (bather load) and then divide the remainder by 3.

So, if you have a large hot tub that only you or your partner use, you will need to change the water less frequently than if you have a smaller hot tub used regularly by the family.

Personally, I never really notice this calculation as there are many other factors that influence when I change the hot tub water.

I tend to change mine less frequently than every three months since I am usually the only person who uses it regularly. I will sometimes leave it for up to six months, even up to a year, provided I have none of the other factors above that make me change it.

Foam

Foam occurs when surfactants (like salt, detergent and other organic compounds) combine with water and air. The “hydrophobic” (not attracted to water) nature of surfactants reduces the surface tension, creating this bubbling upon the water’s surface.

Before you begin removing the foam or cleaning the water altogether, check all the levels of the tub water. Calcium, sanitizer and pH should be balanced and at proper rates.

If they are in balance, go ahead and add a chemical foam remover such as Pool & Spa Defoamer to see if that takes care of the problem. If not, you’ll have to clean your tub and change the water. If your levels are off, switch the water out without using a foam remover.

Read my article Why do hot tubs foam

Cloudy water

If your water is cloudy, and you have tried shocking it without any improvement, I would just cut your losses and empty the hot tub, clean it and refill it.

Read my article Why is my hot tub cloudy

Problems with balancing chemicals

If you are struggling to balance your water chemistry to maintain water quality, there comes a time to give up.

For example, if you use test strips that show you need to add something to change the levels and that then puts something else out of balance, I suggest you stop chasing your tail and empty it and refill it with clean water.

Smell

Inevitably, at some point, you will lift up the hot tub cover and be met with an unpleasant, almost moldy and foul smell. Although, in theory, you can start adding chemicals to counteract this, personally, I just change the dirty water in my hot tub as I try to avoid sitting in what is basically chemical soup.

Urine

Perhaps some wouldn’t believe it, but sometimes people, particularly children, pee in a hot tub. The hot tub water gets the blood pumping quicker so urine is produced more quickly than usual. Perhaps it is tempting to pee where they are rather than getting out, getting dried and visiting the bathroom.

Whatever the reason, if you suspect this to be the case, then change the water.

A hot tub has a relatively small volume of water (compared to a swimming pool, for example), so the concentration may be quite high. When chlorine reacts to the urine, it can produce chloramine, which can cause breathing problems.

How to change water in hot tub

There are several ways to drain your hot tub, all of which I have used at some point in the past twenty years during which I have owned hot tubs.

Briefly, your options are:

• Drain it using a garden hose to siphon out the water
• Use a submersible pump
• Use the drain plug on the hot tub
• If you have a swimming pool close to the hot tub, then you can use the vacuum pipe and the pool pump

For a full explanation and step-by-step guide, then please read my article How to drain a hot tub

Can you do a partial water change?

If your hot tub has high TDS (total dissolved solids), a quick partial water change with fresh water can make a big difference. Lower TDS levels make maintaining the hot tub’s water chemistry significantly easier.

The advantages are that it reduces TDS levels and means the hot tub will reach its ideal temperature much quicker, so it can be used again sooner. This is particularly useful if the hot tub is outside in a cold winter (see below).

Can you change hot tub water in winter?

Fortunately, where I live, the temperature in winter never drops below 50ºF, so freezing is never a problem. However, if you live in a colder climate and your hot tub is outdoors, then it can be an issue.

The hot tub water won’t freeze when it’s at its usual temperature because the tub’s thermostat turns on the heater when the temperature starts to drop.

But when you empty it and refill it with the hose, the water temperature will be very low, so there is a potential for it to freeze.

There are a few things you can do to ensure that it doesn’t freeze:

• If you know you are in for a very cold spell then perhaps delay emptying and refilling until it is over
• Since nighttime temperatures are normally much lower, empty and refill the tub in the morning to give the tub’s heater time to raise the water temperature before nightfall.
• You could add a few buckets of hot water when refilling to bring the water temperature up quickly.
• If the hot tub water is not too dirty, you could partially empty it and refill it so that the resulting temperature of the mixed old hot and new cold water is higher.

Related post

Should I leave my hot tub on all the time?

Best hot tub temperature in summer and winter?

How Many Gallons of Water in A Hot Tub? How to Calculate