How Many Gallons In A Hot Tub

Whether you're concerned about a patio or deck supporting the weight of a standard hot tub, or have water usage in mind, determining your hot tub's gallon capacity is crucial.

Several factors go into calculating out how many gallons of water are in your hot tub, including the size, shape, and capacity.

We're going to break it all down and help you determine exactly how much water your hot tub holds.

Let's get started!

Calculate How Many Gallons of Water Your Hot Tub Holds Based On Size

On average, the smallest hot tubs that you'll find from manufacturers are two-person hot tubs. Typically, two-person hot tubs will hold anywhere from 150-220 gallons of water. A standard deck should not have any problem supporting the weight of a two-person hot tub.

For those who want to take it up and get a three-person hot tub, you should expect it to hold anywhere from 200-300 gallons of water. Similar to a two-person hot tub, a three-person hot tub should be fine on a standard deck.

If you're looking at a 4-6-person hot tub, you may need to start considering some reinforcements. An average 6-person hot tub typically holds anywhere from 320-475 gallons of water. A 6-person hot tub may present challenges for those who place their hot tub on the deck depending on the number of people who are in it at one time.

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How To Figure Out The Precise Number of Gallons Your Hot Tub Can Hold

There are a few ways to calculate how many gallons of water your hot tub's interior can handle.

One of the easiest ways to figure out how many gallons you'll need for your hot tub is to look at the manual.

If you misplaced the manual a while back, you can always run a quick Google search to see if you can find the amount online.

If you can't find that information, you can also calculate the number of gallons of water your hot tub can hold manually.

To get started, you'll first need to grab a tape measure.

If you are dealing with a square or rectangular hot tub, you will need to use your tape measure to figure out the length, width, and depth. Once you have those measurements, you will need to multiply the width by the depth. Divide that number by 1,728. (1,728 is the figure that we use to convert the number of cubic inches to the number of cubic feet)
Round hot tubs are different. If you have a round hot tub, you must measure the width across the central point of the tub and measure the depth. Once you have the diameter, you will multiply the diameter by the depth. Divide that number by 1,728.
If your hot tub has seats, multiply your result by 2.4.
If your hot tub does not have seats, multiply the result by 4.8 instead.
Once you have finished, you will know how many gallons of water fit in your hot tub's interior.

Filling Method

Lastly, you can use the timed fill method. You can figure out the capacity of your hot tub and how many gallons it holds by filling your hot tub with a hose. Make sure you time the filling process so you know how long it took to fill.

Start by turning your hose on and running it in your hot tub.
Use a timer to keep track of how long it takes to reach capacity. Enjoy a glass of wine while you wait. You deserve it!
Once the hot tub is full, you will need to calculate how many SECONDS it took to fill.Get a single gallon jug

Use your hose to fill up the jug with water and time and stop the timer when it is full. The number you stop at when the jug is full is your flow rate per gallon.
Divide the time it took to fill your spa with water by the time you just recorded with the jug. This number will give you an approximation as to how many gallons are in your hot tub.

Figuring Out How Many Gallons Your Hot Tub Can Hold

A few takeaways here:

The gallons of water in your hot tub will depend on the dimensions (length, depth, width), whether your hot tub has seats, and the number of seats your hot tub has.
A 6-person hot tub will hold far more than a 2-person hot tub (swim spas are an entirely different game)
There are plenty of ways to manually measure how many gallons are in a hot tub, though the easiest way is to look for your hot tub manual.

We hope that this was helpful in giving you an idea of how many gallons you can expect to find in the average hot tub!

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