How Many Gallons of Water Are in a Hot Tub?

By Jon Filson

Hydropool Hot Tubs and Swim Spas

Published May 15, 2024

If you are considering purchasing a hot tub or a swim spa, you may be wondering how many gallons of water end up in it.

This often happens when people are trying to calculate the amount of chemicals they require in their hot tub or swim spa. You might also be concerned about the cost of the water or it just might be curiosity. But we do get asked about it at our Hydropool retail stores, so we want to give the best answer to it that we can.  

Here’s our code on how we calculate water volume (so you can too):

  • Length (inches/inside) X Width (in inches/inside) X Average Water Depth (inches) X 0.00434 = Volume in Gallons
  • Length (Meters) X Width (Meters) X Average Water Depth (Meters) X 1000 = Volume in Liters

So if you have those measurements on a hot tub or swim spa you’re looking at, you can calculate it. Often this information will be included in the “specifications” of any hot tub or swim spa you want to consider. You should be able to find this in an owner’s manual or on a product web page.  

But don’t worry, we’re going to break this down further, so you can know how many gallons are in a swim spa and how many gallons are in a hot tub:

  • People often want a rough estimate of the “average hot tub” or “average swim spa"
  • People generally want to know the volume that’s specific to their hot tub or swim spa

We promise all of those things in this article! Have a look, as we talk about both averages and specific models.

 

 

What is the Amount of Water in an Average Hot Tub?

This is tricky, because there is no average hot tub. A hot tub that holds 4-6 people will typically hold around 375 gallons of water. But that number can go up to 600 depending on the size of the hot tub.

What is the Average Amount of Water in a Swim Spa?

Again, here’s the range: As an estimate swim spas can typically range from 1450 gallons for a small model to about 2500 for a larger, family-sized spa.

How Many Gallons in a Two-Person Hot Tub?

We don’t sell a two-person hot tub! But we can tell it’s generally about 170-200 gallons.

How Many Gallons in a Three-Person Hot Tub?

How Many Gallons in a Four-Person Hot Tub?

How Many Gallons in a Five-Person Hot Tub?

How Many Gallons in a Six-Person Hot Tub?

How Many Gallons in a Seven-Person Hot Tub?

How Many Gallons in an Eight-Person Hot Tub?

  • We don’t sell one of those at Hydropool, but it would be 400-650 US gal, depending on the model.

How Many Gallons in a 13-Foot Swim Spa?

How Many Gallons in a 14-Foot Swim Spa?

How Many Gallons in a 16-Foot Swim Spa?

How Many Gallons in a 17-Foot Swim Spa?

How Many Gallons in a 19-Foot Swim Spa?

How Much Water Does a Hot Tub (or a Swim Spa) Hold?

If you’re shopping for a swim spa or hot tub, or if you have one already, knowing how much water it holds is part of ownership. In some cases, the volume it holds lets you determine the amount of chemicals you require to keep it functional.

In most cases, your hot tub manual will have the specifications of how much water it holds. You can also calculate it with the formula we gave you above. Or you can use our list of hot tub and swim spa sizes to figure out approximately how much water your swim spa or hot tub holds.

We hope this article has helped you figure out your water volume questions. But if you still have more, don’t hesitate to reach out to a local dealer for more information. 

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