5 Reasons Your Hot Tub Water Level Could Be Dropping

Jennifer Rhodes

By Jennifer Rhodes · Updated

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When you're excited to go in your hot tub after a long day, it sure is frustrating to pull off the cover and notice that the water level seems lower than normal. There are a few reasons why your hot tub water level could be dropping—and thankfully, most of them you should be able to fix with ease.

In this article, we will help you identify the most common reasons why your hot tub water level could be dropping so you can fix it and get back to enjoying your hot tub without this headache.

Why is your hot tub water level dropping?

If you notice that your hot tub water level isn't what it usually is, don't worry. There are some reasons why this might be happening that are totally normal, expected parts of hot tub ownership.

There are some times when water loss could be a concern, but that's commonly not the case if you take good care of your hot tub.

We will discuss both the normal and abnormal reasons for a drop in your hot tub's water level so you feel prepared to tackle any situation like this, now or in the future. Here are the 5 most common reasons that your hot tub water level could be dropping, and what to do about it:

1. Normal evaporation

The first thing to know is that some water level change is normal in your hot tub.

Evaporation does happen due to the high temperature of the water and normal use. No matter how diligent you are with replacing the cover and other preventative maintenance, evaporation happens during use (and it should).

Make sure you are following the correct steps to maintain your hot tub cover so that it seals as well as possible. This will help to reduce water loss through evaporation.

You should expect to see only about a change of an inch of water per week when it comes to evaporation water loss in hot tubs. This is the normal, expected amount that most hot tub owners will observe. If this is all you are noticing, there is nothing for you to do.

2. Cover left off

Replacing the cover when your hot tub is not in use is one of the best ways to prolong the life of your hot tub in so many ways, but it also has a big impact on preventing water loss.

When the cover is left off your hot tub (or even if the cover is replaced but just fits poorly or is broken), a lot can go wrong. The biggest issues with that are that your hot tub has to work a lot harder to maintain the water temperature (not very energy-efficient!) and the water evaporates much more quickly.

If you accidentally left the cover off overnight or after your last use and you've noticed a big drop in water, just replace the cover and make sure it is on tightly. Keep an eye on your hot tub over the next several days and make sure it doesn't continue to lose water, which would be a sign that something else might be wrong.

3. Leak problem

Unfortunately, sometimes a low water level in your hot tub is due to more than just evaporation. In some rare cases (especially with older or poorly maintained hot tubs), you might be dealing with a leak.

You can usually tell if you have a leaky hot tub because the water level will drastically drop in a short period of time. Normal water loss from evaporation or overflow is usually minimal, but a leak will often be several inches of water loss in as little as a few hours.

If you think there is a chance that your hot tub is leaking, do your best to see if you can see an obvious source of the leak. Check for puddling of water around your hot tub or in any of the mechanical components, and check the insulation under the cabinet for any moisture.

Any information you can provide to a service technician to help them identify and resolve the issue will be helpful. In the meantime, don't refill the spa until you can get someone to come out and fix the issue, as this will make the problem worse.

4. Too many users

An often overlooked reason why you might have a lower-than-usual water level in your hot tub could be the result of how many people you packed into it at your last party.

It's normal to want to invite tons of people over to enjoy your hot tub, but it's important to remember the capacity and user limits on your hot tub when you will be having guests.

Having too many people in the hot tub causes water displacement, which can cause a significant amount of water loss.

This doesn't mean that you can never enjoy your hot tub with friends, it just means to be smart about it. Make sure you only have as many people as your hot tub can comfortably hold at one time.

If you start to notice excessive splashing or overflow when it is full, consider getting out—or plan to replace the water as soon as the party's over.

5. Seasonal temperature adjustments

Believe it or not, what the weather is doing outside can have quite a significant impact on your hot tub water level. When seasons change and temperatures drop, often the rate at which the water in your hot tub evaporates will change.

For this reason, if you live somewhere with four pronounced different seasons, you may notice that your water level drops more drastically in the winter than it does in the spring and summer. This is just because your hot tub is working a bit harder to maintain its temperature in the cold and is evaporating off a bit more water.

Even with the best insulation and a well sealed cover, it's still possible to experience some amount of evaporation.


How much water is normal to lose from your hot tub?

It's normal to expect to lose about 1-2" of water in your hot tub per week. This accounts for normal evaporation. It may fluctuate seasonally or based on usage but usually, anything under 2 inches per week is considered normal and nothing to worry about.

Can you add water to a hot tub when it's low?

If you notice that your hot tub water level is low and you have confirmed that it is due to a factor other than a leak or other mechanical problem, it is fine (and actually encouraged) to add water to replace what was lost.

Adding water to your hot tub regularly when needed will help keep your hot tub working properly and help you continue to stay on top of your water levels and notice if the problem persists. Just be sure to test and adjust your water balance after.

If your hot tub is actively leaking water though, just adding more water will not solve the problem, and should be avoided until the issue is fixed.


When you notice a drop in the water levels inside your hot tub, usually it's pretty easy to figure out why.

Chances are, it is a natural part of the evaporation process or something that you can easily fix like making sure to replace the cover after each use and not overloading your hot tub with all your friends.

The biggest thing to know is that if you notice a low water level in your hot tub, don't panic right away! As long as you haven't lost several inches of water overnight, usually the water loss isn't anything major to worry about, and can be fixed easily.

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