How Long Does It Take to Fill a Hot Tub?

Jennifer Rhodes

By Jennifer Rhodes · Updated

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If you just bought a new hot tub, of course you're excited to use it for the first time! But in all of your excitement, don't forget that you'll need to allow the appropriate amount of time to fill and balance your hot tub before enjoying it for the first time.

Depending on your water pressure and the size of the spa, filling a hot tub can take anywhere from 30 minutes to 2 hours on average. Most hot tubs will take around 60-90 minutes to fill.

In this article, I'll help you figure out exactly how long it will take to fill your specific hot tub, and what to expect during the process—so you can get to the fun part of enjoying your hot tub.

What are the factors that affect how long it will take to fill a hot tub?

When it comes to how quickly you can get your hot tub full of water and ready to enjoy, there are two main things that will impact the length of time it will take: your water pressure and the size of the hot tub you need to fill. Both of these together will determine how quickly you can fill your hot tub.

Water pressure

Why does water pressure matter when it comes to filling your hot tub? If you have strong water pressure in your area, you are able to send more water through the hose at a faster rate than someone with less pressure. More water at a faster rate means that your hot tub will fill more quickly.

The best thing to do is to put your garden hose into your hot tub and open the faucet as far as it can go. This will get you the maximum water pressure available to you in your area.

Just keep an eye on the hose as the hot tub starts to fill to make sure that it doesn't fall out or overflow.

Hot tub size

The other piece of the puzzle is the size of your hot tub. This one is simple to understand. A larger hot tub means that it will take more water to fill than a smaller hot tub, so naturally it will take longer to fill because more gallons of water are needed.

While most people tend to gravitate towards the standard size (and shape) hot tubs that fit 4-8 people, there are all kinds of custom sizes that you can get to meet your individual needs. This is where some degree of variation can come in.

For example, if you have a small hot tub or an extra-large spa, you could be looking at a much shorter or longer fill time.

How to estimate hot tub fill time

There is a simple trick you can use to get a ballpark estimate of how long you'll have to wait for your hot tub to fill.

You will need:

  • A 5 gallon bucket
  • A timer
  • Your garden hose
  • The size of your spa in gallons

How to perform this test:

  1. Take the empty bucket, and go and stand next to your empty spa.
  2. Turn on the hose, and start the timer as you start to fill the bucket.
  3. When the bucket is full, stop the timer.
  4. Divide the spa size by the bucket size.
  5. Multiply that number by the time to get the total in seconds.
  6. Divide that number by 60 to get the time in minutes.

As an example, let's say your spa is 300 gallons, and it took 30 seconds to fill your bucket. 300 / 5 = 60 and 60 x 30 = 1800 seconds. 1800 / 60 gives you 30 minutes. So that is your estimate.

Be sure to keep an eye on the spa while it's filling though—it's not an exact calculation, so you might need a little more or a little less time in reality. You can time the whole process from empty to full so you'll have a more accurate idea for next time.

How long does it take to heat a hot tub?

Now that you've got your hot tub full, it's time to jump in and enjoy a nice, relaxing soak, right? Not so fast! It's important to remember that you also have to give your hot tub time to heat up the water you just put into it.

Heating the water can be an arguably more frustrating process than filling the hot tub because it takes significantly longer. Depending on the size of your hot tub and how hot you set the thermostat to, it can take anywhere from 3-8 hours for your hot tub to come up to temperature.

A good idea is to fill your hot tub in the evening and then set the temperature and allow it to heat overnight while you sleep. That way the hot tub should be plenty warm for you to enjoy the next day.

I also have some tips on how to make your hot tub heat up faster which can speed up the process.

How long does it take to set up a hot tub?

There are three main stages to setting up a hot tub so that it's ready for use. We can combine them all to get a total estimate of around 6-14.5 hours:

Filling60-90 minutes
Heating3-8 hours
Balancing2-5 hours

I like to set aside a full weekend for water changes, so I can drain, clean, and fill with fresh water on the Saturday, leave it to heat up overnight, and then balance the water on Sunday.

By Sunday evening you'll be able to enjoy the fruits of your labor with a lovely relaxing soak!

How often do you have to refill your hot tub?

Once you get your hot tub up and running for the first time, you might think you never want to do that again. And while you don't have to fill your hot tub with fresh water very often, you should do it as part of a regular maintenance schedule—at least once every quarter is a good rule of thumb.

The reason you should be fully draining your hot tub and replacing it with fresh water every quarter or so is to prevent dirt buildup and to give your hot tub a thorough deep clean. There's only so much sanitizing chemicals can do, so eventually the water will need to be replaced.

Can you drain old hot tub water in your yard?

Refilling your hot tub first means disposing of the existing water inside your hot tub. No matter how you slice it, you have a lot of water to get rid of so it's important to plan accordingly.

The good news is that if your hot tub is located outside in your yard, there are several things you can do with this water. I have another post on eco-friendly ways to dispose of hot tub water which can give you some ideas.

If your hot tub is inside, you will need to connect a hose and direct the water into the nearest appropriate drain.

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