Do Hot Tubs Lose Water?

I’ve owned hot tubs 3 different times in my life, and while I love using them with my family, I have wondered, do hot tubs lose water?

So I decided to educate myself a little and find out.

Hot tubs will naturally lose some water due to evaporation, but not more than a few inches a week unless the cover is left open or it sees heavy use. A well-fitting cover can minimize water loss from evaporation. Lowering the temp when not in use for long periods or setting it to the economy setting helps also.

But there’s a lot more to get into about what evaporation, winterizing hot tubs, and finding and fixing leaks, so let’s keep going!

How much water do hot tubs lose?

Lots of factors come into play with normal hot tub evaporation.

  • The temp the hot tub is set to
  • Temperature and humidity of where you live
  • The quality of your cover and how tight it fits
  • How frequently the cover is left open
  • Frequency of use and how many users

That being said, there are some baselines we can use.

Frequent use by multiple guests means both that the lid will be off frequently and there will be some water soaked into swim suits & hair and splashed out of the tub.

Hot tub water also tends to evaporate much faster in a dryer climate compared to a humid one where there’s lots of moisture in the air. Also, the hotter you set your tub, the more prone to evaporation it will be.

Heavy use could see as much as 1-2 inches of loss each week, especially during winter.

Does hot tub water evaporate in winter?

In short, while hot tub water evaporates all year, it does tend to evaporate faster when it’s cold outside since the hot tub water is significantly warmer than the ambient air temperature.

Humidity also affects the evaporation rate, so the more humid your air, the less evaporation you will see.

Can you add water to a hot tub?


In fact, if you never added water to a hot tub, it would eventually run out altogether, to say nothing of not being very pleasant to be in.

I just fill mine with a garden hose to the appropriate level and then treat with chemicals and test with my test strips to ensure they are properly balanced.

It’s also a good idea to completely change your water from time to time as well.

How often should I change my hot tub water?

Even treating with chemicals and changing your filters regularly, it’s still easy for your hot tub water to get dirty and oily; especially with frequent use.

For a hot tub that sees somewhat regular use by a family of 4, you probably want to change your water about every 3-4 months or at least twice a year.

How do I change the water in my hot tub?

All hot tubs have a drain underneath the tub where your equipment is.

Unfortunately, every brand does this a little differently. My 1st hot tub had a hose spigot on the side so I just hooked up a garden hose and directed it away from the tub and could simply turn the hose knob to drain the tub.

My 2nd tub I had to open the panel (with a screwdriver) to get to the equipment and remove a large hose which had a valve on the end of it.

You can also buy something called a sump pump to speed up the process as it drains the tub QUICK!

My favorite sump pump to drain my hot tub is the EZ Hot Tub and Pool Submersible Drain Pump.

It has flawless reviews on Amazon and it’s an Amazon’s Choice pick. It drains 2000 gallons an hour (the average tub is about 400) and it comes with a 25′ drain hose, so you can drain it well away from your tub and house.

CLICK HERE to check current prices on Amazon.

No matter how you drain it, cut the power at the breaker panel to ensure the pump or heater don’t come on during draining as it could damage the equipment.

How do you keep a hot tub from freezing in the winter?

Personally, I LOVE using my hot tub in winter.

I love the hot water submerged up to my neck with the cool brisk air above me. That being said, there are some precautions you should take in winter, such as:

  • Monitor water levels regularly and add more as needed
  • Make sure your heater is on a timer and comes on every 15 to 20 minutes to circulate and heat the water (most modern hot tubs do this automatically)
  • Get a good insulated cover and keep it on tight when not in use
  • Make sure to turn off the jets every time you exit the tub
  • Consider a backup battery or solar backup on your pump if your area is often below freezing and prone to electrical outages

Can I drain a hot tub in winter?

As I said, I LOVE using my hot tub in the winter.

If you don’t though, you can certainly drain the tub during the winter months. This helps save electricity, saves on water treatment chemicals, and helps prevent bacteria and algae growth.

Is it OK to leave a hot tub empty in the winter?

Yes, is the short answer.

Drain the tub following the tips I walked you through above in the “how do I change the water in my hot tub” section. You’ll initially turn on the jets to flush any water or debris out of the lines. But then as it starts to drain, turn the power off at the breaker.

Next, take out the filter. If it’s new(ish) you’ll want to clean it off thoroughly with a hose or in the sink with a sprayer. Then allow it to dry and keep it somewhere inside where it will stay clean while being stored.

If your filter is old, go ahead and toss it, order a new one (keep in the box) and have it ready when you fill it back up.

Once your hot tub is drained down to close to the bottom, you’ll likely need to use a wet-dry vacuum to remove the last bits of water from the bottom. You can also use the vac to suck or blow into the jets to suck out or push out any remaining water.

Wipe the tub clean with a dry towel and then thoroughly close the cover.

Don’t have a wet-dry vac? My favorite one is the Vacmaster. It’s got a 6-gallon tank, has wheels so it rolls as you move, has thousands of awesome reviews, free shipping, and is an Amazon’s Choice product.

CLICK HERE to check current prices on Amazon.

What temperature should I keep my hot tub in the winter?

Personally, I set my tub at 98° all year.

That way it’s not too hot in summer, but it’s still nice and warm in winter. I also have a toddler though and I don’t want it super hot for her. Plus being under 100°, we can stay in a little longer if we wish.

Of course in winter, the hotter you set it the more water will evaporate. There will also be a bigger difference between the air temp and water temp (which feels good going in but a little cold getting out).

That being said, the most common temperatures people set their hot tubs to, including winter, is between 102-104°. I don’t personally think you should go above 104° or below 90°, so play around with a few temps and see what feels right for you.

How do I find a leak in my hot tub?

If you notice a significant loss of water in the tub requiring weekly or daily refilling then you likely have a leak.

There are a number of places where you can have a leak, such as:

  • Where the pump connects to the heater
  • On the other end of the heater
  • At the jets where they fit into the tub
  • In the lines that run under the tub

Unfortunately, not all of those places are easy to get to, as some of the jets will be encased on spray on foam or insulation.

Start by removing at least 1 side of the panel around your hot tub.

Some are wood and some are plastic or vinyl, and all are different, but yours should pop open relatively easily with a screwdriver or cordless drill.

Once you can see under the tub, see if you can find where the water is pooling on the ground or if you see it dripping.

Since the pipes are pumping hot water, and heat naturally causes expansion, it’s not uncommon for fixtures to come loose over time or for parts to wear out.

How do I fix leaks in my hot tub?

Once you’ve found the leak(s), first try tightening fittings by hand.  In most cases, you won’t want to risk overtightening with a wrench.

You can also apply some JB Weld WaterWeld Epoxy Putty (click to see current price on Amazon) on any pipes where small holes have developed.

It is designed to apply under wet conditions and in my experience using it on my tub, it works great. Just don’t apply it to any fittings where you may later want to open or tighten them.

Lastly, I will say what has worked the best for me in fixing hot tub leaks is a product called Marlig Fix-a-Leak.

I just remove the hot tub’s filter and pour in where the water gets sucked in by the pump. Then let it go to work.

It’s a liquid, but it’s heavier than water so it naturally flows to wherever the lowest point it which is usually where the leak(s) is.

If you have leaks, you’ll definitely want to check out my Marlig Fix-a-Leak Review of exactly how it works, how to use it step-by-step, and see if you don’t love it as much as I do. Just click the link to read it on my site.

Did I cover all your questions about hot tubs losing water?

In this post, we took an in-depth look at hot tubs and what causes hot tubs to lose water.

We explored normal water evaporation. But we also answered questions about how to treat your hot tub in winter, and what to do if you think you have a leak.

If you need help replacing hot tub equipment or refurbishing an older one, I’ve done just that with an old one I bought online for next to nothing.

I detail the entire process in one of my most popular posts. So check out my post on How to Fix Up a Hot Tub to learn more about just how easy it is!

Are you seeing significant water loss in your hot tub?


Photo credits (that aren’t mine or which require attribution):
Hot tub moving pictures taken from the Unique Moving & Hauling Facebook Page

Jeff Campbell

Jeff Campbell is a husband, father, martial artist, budget-master, Disney-addict, musician, and recovering foodie having spent over 2 decades as a leader for Whole Foods Market. Click to learn more about me

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