Where Does In Foam Hot Tub Come From and How Can I Prevent It

In this post, we will be discussing some of the most common causes of foam in hot tubs and how to stop them from happening again.

A hot tub is a great way to relax and unwind, but sometimes foam can occur for no apparent reason. A number of different things can cause this, so it's important to know the leading causes of foam in a hot tub. The problem is that they can cause severe damage to your hot tub and can even cause health issues. The good news is that you can easily prevent this from happening again by following a few simple steps.

What Causes Foam in a Hot Tub?

Your hot tub water contains a certain amount of surfactant even when maintained properly. Surfactants are used in many household products like soaps and detergents. They loosen water molecules, making it easier for other stuff like air and oil to get in.

The foam you see on a hot tub is essentially the same thing. After some time, these surfactants start to build up. You won't notice it until you flip the jets putting air into the mix, turning your hot tub into a foamy mess.

foam in hot tub featured image

Surfactants can come from many sources, but the most common ones include personal care products, beverages, and the human body. We get rid of these by keeping balanced water chemistry, sanitizing, and other chemicals that break down these surfactants. However, sometimes we miss a day or two of maintenance, and surfactants start to build up.

These are the three main sources you should be watching out for:

  • Personal Care Products. Every time we use our hot tub, we bring along everything we use in our bodies to it, like makeup, conditioner, shampoo, hairspray, deodorant, and so on. More contaminants mean your sanitizing agents need to work harder. Showering before taking a dip will help remove some of these surfactants. Another major culprit is the soap in our clothing, particularly detergents that are left out after washing them. All of these can mess with your hot tub's chemical balance, so keep that in mind.
  • While enjoying the spa, make sure you don't spill anything in it. Foaming is just one of the problems you have to deal with if you accidentally knock over a glass. You also need to clean the edges or maybe even have to replace the water. We're not saying you can't drink while doing a hot tub; just keep them at a safe distance, so you don't make a mess.
  • Human body. You might not know it, but our bodies are also one of the major reasons surfactants accumulate in the water. Things like oils and dead skin cells are thrown into the mix, and sanitizing chemicals need to deal with them as well. As a result, they become overburdened and unable to break down most of the surfactants in your hot tub. Showering before going into the hot tub can help lessen the impact caused by body oils and dead proteins.

How to Get Rid of Foam In Your Hot Tub

Foam showing up in your hot tub is a sign that your water chemistry is off and sanitizers can no longer handle the number of contaminants and surfactants present in the water. In most cases, it's already too late, and all you can do is either temporarily fix the issue or replace the water altogether.

how to get rid of foam in your hot tub

Here's what you need to do and how you can prevent this from happening ever again.

  1. Test your hot tub's water chemistry. You should be doing this from day one as part of your regular maintenance checkup. But just in case you miss a couple of days or after heavy use, you want to make sure your water chemistry and chlorine/bromine levels are still in good shape and bring them up to optimum levels as soon as possible. Also, take note of your hot tub water's "calcium hardness." Low calcium can cause problems like corrosion and etching in your finishes.
  2. Use anti-foam chemicals for quick fixes. Replacing your water might not be an option if you have a party coming up. Draining, cleaning, and refilling your hot tub can take a while, so you need something to get rid of the foam quickly. Anti-foam chemicals can get you out in a pinch. Foam remover can fix the issue and last you up to 24 hours. However, this is just a quick fix, and they don't address the root cause.
  3. Drain and refill. After discovering the causes of foam in your hot tub, it's time to reset everything with a basic drain, clean, and refill. You want to flush your hot tub's plumbing lines as these too are already covered in gunk. Keep a record of your hot tub's water chemistry and monitor the pH, alkalinity, and chlorine/bromine levels and shock your hot tub at least once a week. Preventing a foamy hot tub costs less than replacing the water every now and then.


Prevention is always better than cure. The good thing with a well-maintained hot tub is that you don't have to deal with a foamy hot tub - ever. However, you still need to change the water once every three months, and you have to shock your hot tub every once in a while. But that wouldn't cost you much, and you'd probably spend less than an hour doing them.