How To Deal With Foamy Hot Tub Water

foam in hot tub

Foamy water sounds fun until it’s in your hot tub. It kinda ruins the sparkling clear water effect you’re going for by keeping your chemicals balanced and your surroundings clean.

The truth is that foam in your hot tub is probably not harmful at all, but it sure can look nasty lurking on top of the water. And if your friends stop by, they’re probably going to pass on the dip in the spa.

There go your bragging rights!

But don’t worry…you can easily get rid of it. Here’s everything you need to know…

Why is there foam in my hot tub?

Foam in a hot tub is caused when Total Dissolved Solids (TDS) levels build up on the surface of the water by getting stirred up with the jets.

So, what the heck are total dissolved solids?

If you have a queasy stomach, here’s where you might want to keep scrolling. 

TDS is mostly made up of all the gross stuff that comes off the human body – namely dead skin cells, oils, sweat, urine, and products like deodorant and lotion. In other words, when you have more bathers, you’re likely to have more TDS.

But it’s not just body fluids and products that cause a foamy hot tub. It can also be a buildup of various chemicals, cleaners, leaves, debris, unbalanced pH, or high calcium hardness. Even spilling a beverage or two in the spa can cause a problem.

Most filters do a good job of sifting this gunk out, but when there’s an excess, it can still build up over time. And it doesn’t take long for it to start showing up in a foamy film on top of the spa water.

Is foam in a hot tub bad?

Depending on how you look at it, foam in a hot tub is not usually bad. Or it’s at least not gonna kill you. 

But it can eventually become a breeding ground for some pretty nasty bacteria. 

I say “eventually” because almost every hot tub has just a little foam and it’s usually completely harmless. But if you’re allowing it to build up and not keeping your chemicals in check, it can definitely harbor some germs.

And even before there’s anything to worry about with the foam, it’s still pretty unsightly and can leave a buildup that’s hard to clean. Plus, who wants to soak in other people’s filth? 

Or even your own, for that matter!

How much foam is normal?

Almost every hot tub will have some foam, especially around the edges. It’s just pretty much unavoidable. 

But if there’s more than an inch or so of it, you’ll probably want to address it. This is when it can start to carry germs. 

How do I stop my hot tub from foaming? 

If you have a problem with foam in your hot tub, there are some things you can do to fix it. 

First things first, check your chemical levels with your regular testing kit. Make sure they’re in these ranges:

pH: 7.2-7.8

Total alkalinity (TA): 100-120 parts per million (ppm)

Chlorine: 1.0-3.0 ppm

Calcium hardness: 100-250 ppm

If you need to raise or lower the pH or TA levels, use an increaser or decreaser according to the package directions, then retest to see if they’re balanced out. Repeat this process until your chemicals are in range. 

If the sanitizer levels are low, add more to get it in the proper range. 

If the calcium hardness level is too high, there are not a lot of options other than to drain the water and start over.

After adjusting your chemicals, it’s always a good idea to clean your filters well. This usually just requires a quick spraying off with a hose unless it’s really dirty.

A quicker fix for the foam is to add an antifoaming agent or defoamer to the water. Most products only require a few drops to dissolve the foam within 24 hours.

Lastly, the perfect way to get rid of foam in a hot tub is to drain the water, clean the tub and start all over with fresh water. You can read more about that here, but here’s the basic rundown:

  1. Flush the lines

  2. Disconnect the power source

  3. Drain the hot tub

  4. Clean the filter

  5. Clean the hot tub interior

  6. Refill the hot tub

  7. Turn the power back on 

  8. Add your chemicals

6 Tips to Prevent Hot Tub Foam in the Future

The best way to prevent any problems, including foam, is to test your chemicals regularly. This will ensure that your pH and calcium hardness levels are balanced so you’re not getting deposits or buildup in the tub. 

Additionally, though, there are a few other tips that will keep that nasty foam at bay.

  1. Shower before getting in the hot tub.

If you can get everyone on board with this practice, you’ll have an easier time keeping beauty product buildup out of the water. Of course, you’ll also have to make sure you don’t add lotion or sunscreen before hopping in.

  1. Keep your head out of the water.

Same principle here. If you can keep your head above water, you’ll keep out hairspray, face creams, and makeup.

  1. Keep drinks out of the water.

Spilled drinks in the water can cause buildup, especially anything sugary or heavy.

  1. Don’t use fabric softener on swimsuits.

Wash swimsuits with mild detergent and hang to dry. Fabric softener and other chemicals can leach out into the hot tub water.

  1. Rinse off swimsuits before entering.

If your suit’s been laying around or if you haven’t just washed it, rinse it off with fresh water before getting into the pool with it.

  1. Rinse off your hot tub accessories.

Cute little floating cup holders, waterproof speakers, and water pillows are all great to have. But if they’ve been laying around outside, they can accumulate dirt or debris that can build up in the water.


To wrap it up, hot tub foam is a preventable but typically harmless occurrence. But it’s important to keep it under control to avoid potential cleaning problems. 

Of course, as we always say, prevention is the best remedy for anything pertaining to hot tubs or pools (or life!). So, stay on top of your weekly maintenance chores like testing your chemicals and cleaning out debris.

And when you notice a small problem cropping up, take care of it right away. If you never let things get out of hand, you’ll spend a lot less time working and a lot more time soaking.

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