How Often Should You Change the Water in a Hot Tub?

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It seems like a no-brainer that the water in a hot tub will eventually get dirty, cloudy, or nasty. But if you’re new to owning one, you’re probably wondering, how often should you change the water in a hot tub? 

Here’s what I’ve learned in owning 4 over the years:

You should change the water in your hot tub every 3-4 months. However, some hot tub brands do sometimes suggest going 6 months before changing the water under certain circumstances.

In this article, I’ll explain how to know if you should change it at 3 months or let it go up to 6 months. But I’ll also get into the things that let you know the water needs to be changed no matter how long it’s been.

Let’s get into it!

Is it bad to not change the water in a hot tub?

Never changing the water in a hot tub is bad, as it will allow bacteria to grow in the water. Even with continually adding sanitizer and shock, biofilm will eventually form, which can render chlorine or bromine ineffective.

Keeping the water clean is an essential part of owning and using a hot tub. 

If you fail to do this, you will not only damage the key components that give you that fantastic spa experience, but you will also damage your health. Bathing in dirty water can lead to a number of different skin and breathing disorders such as folliculitis, coughs, and breathlessness.

The question is, how often should you change the water?

With the right water care and depending on the amount of usage, you can go 4 months without changing the water. And if you are using saltwater in your hot tub, once a year is fine. It is all down to the maintenance regime.

Keeping the water balanced, making sure the level of sanitizer is correct, and cleaning the filter regularly are the key components to maintenance. And don’t wait for the warning signs before changing your water – bad smells, cloudy water, and foam on the surface – make it a part of your regular plan.

So, there is no way around it. You must change your water 3 or 4 times a year, and in between, you have to keep the water in balance.

Can I do a partial water change in my hot tub?

A partial water change can be done in a hot tub. This is a good way to keep the water extra clean in between full water changes. It is also useful when excess debris gets in the water or after a period of extra-heavy use. But don’t do a partial water change in substitute of your regular full water change.

A partial water change is where only part of the water is drained off, and then new water is added to top off.

A partial water change occurs naturally every time you top off the hot tub, as you will continually lose an inch or 2 a month due to evaporation and loss from using the tub.

How much water just evaporates and how can you tell the difference between evaporation and a leak?

Luckily, I get into all that in a recent article, including the 1 thing you might be doing now to your hot tub that almost always results in a leak. Just click that link to read it on my site.

And every time you get out, you take a half-pint of water with you, between what’s on your body and swimsuit. And if you have kids in there, you lose even more from splashing around.

This water needs to be replenished, so you have to top up from time to time with fresh water. You can do this by using the same garden hose you use to fill your tub.

Sometimes you may need to do a partial water change if you have overdone the sanitizer and you want to redress the balance. It will effectively water down the chlorine or bromine with fresh water.

A partial water change should never take the place of a full change. 

You need to clean the surfaces of the tub and flush out the pipes from time to time, and you can only do this by emptying the water and refilling.

How do I change the water in my hot tub?

Change the water in a hot tub by cutting the power and draining the water to an inconspicuous part of the yard using either a garden hose connected to the hot tub’s spigot or a submersible pump. The hose will take 2 hours, whereas the pump will take 15 minutes.

CLICK HERE to check out my submersible pump on Amazon.

But don’t just grab the hose and start the flow of water.

When it comes to changing the water in your hot tub, there are things you need to consider. First of all, where do you want the water to go? Over your garden? Down the drain?

It is not always that straightforward.

Some states have laws about the disposing of water from hot tubs and pools down the storm drain or a combined or sanitary sewer, so you should check this out first or possibly face a hefty fine!

You can drain your hot tub on your lawn in certain circumstances, but you should read this recent article on my website. There will be upwards of 250 gallons to dispose of, and if this is concentrated on a small area, you will damage grass and plants.

Just click on the link to read it on my website.

This water will also contain chemicals which, although diluted, can cause harm if it isn’t spread over a wide area. Most models have a drain spigot which makes it easy. But on some older or budget models, you have to disconnect the pump and drain from there.

Always make sure everything is unplugged or switched off at the main electrical supply before doing this.

From here, you just connect your hose and let the water drain out by gravity. It’s a slow process and could take up to 2 hours, so you may want to look at how to speed things up.

For me, I would use a submersible pump like the Professional EZ Travel Collection drain pump on Amazon. This fully submersible sump pump is available on Amazon and can pump up to 2,000 gallons of water per hour, so a 290 gallon 6-seater hot tub will fully drain in less than 10 minutes.

This pump has a 400-Watt motor, which can be plugged into the same socket as your hot tub, and the overheat prevention mechanism will shut it off when the water level gets too low.

How do you get water out of the bottom of a hot tub after draining? 

For the standing water remaining in a hot tub after draining, the best practice is to use a wet/dry vacuum to vacuum up the excess water. However, you can use a bucket to scoop this water out and then sponge up the last few drops, but this can be laborious.

When you have drained your hot tub, you will always get an inch or two of water at the bottom.

One shop vac I would recommend is the Craftsmen Wet/Dry Vac on Amazon. This heavy-duty vacuum is available with a 12, 16, and 20-gallon capacity. For a hot tub, the 16-gallon model is the perfect size. 

But the larger the capacity, the fewer times you’ll have to empty it.

It has a powerful 6.5 peak HP rear blowing port which is great for cleaning your garage and yard when you’re not draining your hot tub. It comes with a 7-foot hose, 2 extension wands, and 3 types of nozzles to get into all those tight places in the corners of your tub. 

With a 20-foot cord length, it should easily reach your hot tub without the need for an extension cord.

Using a shop-vac is fine so long as it is a wet-dry type. In other words, it is built to suck up water. Take a look at this recent article to see how to do it. 

Click on the link to read it here on my site.

But just a word of caution. Because it uses electricity, despite the fact that it does suck up water, still use caution and care with the vacuum around your hot tub.

Never rest it on the lip of your hot tub as it could easily fall in and cause a shock, tripped, breaker, damage to the vacuum and/or hot tub, or electrocute you if you were in the hot tub at the time.

Rest the base of the wet/dry vac firmly on the ground next to the hot tub and just use the hose to come into contact with the water.

What should I use to clean the inside of my hot tub after draining?

After draining, the best product to clean the hot tub shell is a 50/50 mix of white vinegar and water. It is an excellent way to clean the surfaces without creating foaming issues once you refill. For tough stains, mix in a little baking soda to create a paste and rub this in, then wipe it down with vinegar and water.

There are lots of products around that you can buy.

But you may find you have something you can use already in your kitchen. Dish soap, vinegar, and salt can all be used to clean the surface of the inside of your hot tub.

Using dish soap to clean your hot tub does work. In fact, I wrote about this in a recent article, but if you don’t get rid of all the remaining residue after cleaning, it could end up being really problematic.

Just click that link to read it on my site.

Ordinary household products such as Windex can also be used to clean your hot tub, but whatever you use, you need to rinse the tub thoroughly and wipe it down with a soft cloth before filling it again. 

The rinse water must also be removed by sponging it out or using a shop vac if it’s deeper.

Did I cover all you wanted to know about how often should you change the water in a hot tub?

I hope this gives you the information you need to know about how often you should change the water in your spa.

Changing the water every 3 months or so is essential not only for clear water but also to avoid rashes and bacteria build-up in the water. But if you’re really on top of your water chemistry, and you’re topping off to offset evaporation or even doing occasional partial water changes, you may be okay going 6 months between changes.

And don’t forget to click on those links to read other associated articles here on my site.

Photo which requires attribution:

Hot Tub by Jennifer C. is licensed under CC2.0 and was cropped, edited, color-adjusted, and had a text overlay added.

Jeff Campbell

Jeff Campbell is a husband, father, martial artist, budget-master, Disney-addict, musician, hot tub lover, and recovering foodie having spent over 2 decades as a leader for Whole Foods Market.

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