Foamy Hot Tub Water: Causes, Prevention, And Cleaning 

Foamy hot tub water is a very common problem that occurs when air, water, and surfactants collide. Upon collision, the surfactants create a barrier between the air and water, resulting in foam. While foam in a hot tub generally isn’t harmful, it’s a cause for concern. 

A chemical imbalance, frequent hot tub use, oils, lotions, and beauty products can all cause foamy water. You can prevent hot tub foam by opening the hot tub cover, showering before soaking and washing your bathing suits. Make sure you also test the water and clean the filter regularly. 

If the hot tub foam is because of old or contaminated water, you can get rid of it by draining your tub. However, if the problem is with the water itself, you’ll need to take a different approach. Let’s look at what causes foam in a hot tub, how you can get rid of and prevent foamy water, and how often you should change your filter to enjoy a relaxing soak without worrying about any contaminants. 

What Causes Foam in a Hot Tub?

The top view of blue hot tub with rushing water

Foamy hot tub water prevents you from relaxing in clean, crystal-clear spa water. Although the foam is just a buildup of Total Dissolved Solids, it’s still essential to get rid of it.

The main reason behind foamy hot tub water is failing to sanitize the tub water weekly or after heavy use, like a hot tub party. However, there are other sources for foam buildup as well, the most common ones being:

Oils, Lotions, and Beauty Products

Products such as soap, deodorant, drinks, laundry detergent, cosmetics, body lotions or oils, makeup, hair products, conditioners, and shampoos can cause foam in a hot tub. 

In addition, you should never add bath products like epsom salts or bath bombs to your hot tub.

Chemical Imbalance

High calcium levels can decrease the surface tension of the water in your hot tub, allowing excessive foaming. On the other hand, soft water or low calcium levels can also damage your spa equipment and hot tub. 

While calcium (hardness) levels rarely need adjusting, it’s better to test the water in your hot tubs once a week to prevent low or high calcium levels. However, using cheap chemicals or mixing them inaccurately will cause an imbalanced water pH, resulting in foamy water. 

Other Potential Causes

If you frequently use your hot tub, you might be the culprit behind the foamy water. Regularly soaking in a hot tub sheds dead skin cells and oils from the skin, which throw off the water’s pH balance. 

If you eat or drink something while in the tub, any spills or crumbs will wreak havoc on the pH balance of the water. So, keep food and beverages away from your hot tub to prevent unnecessary contamination. 

How to Get Rid of Foamy Hot Tub Water

The most effective way to get rid of foamy hot tub water is to use hot tub chemicals. Test your water regularly to find out what it’s lacking or overloaded with, and then make adjustments accordingly. 

Sometimes, a bit of extra chlorine (on Amazon) or bromine (on Amazon) will be enough to do the trick. However, if the problem persists, use the appropriate hot tub chemicals to decrease or increase the water’s pH. 

Also, clean your hot tub’s filter to eliminate all the contaminants. Failure to do so could prevent the newly-added chemicals from effectively doing their job.

If the foam doesn’t clear after 24 hours, you’ll have to drain, clean, and thoroughly rinse your tub. When you refill the tub, use a hose filter (on Amazon) to eliminate any water impurities. 

And test the water after refilling the tub, add the necessary chemicals, then let the water circulate for at least 24 hours before testing it again. Once you achieve the proper chemical balance, you can jump back into your hot tub. 

How to Prevent Foam in Your Hot Tub 

The best and easiest way to prevent hot tub foam is to use the right chemicals from trusted brands. There are several other precautions you should take as well, such as:

Shower Before Soaking 

While this is a bit inconvenient, showering before entering your hot tub will help prevent you from contaminating contaminants, such as dirt, lotions, colognes, oils, sweat, deodorants, and perfumes, off your body. 

However, if you don’t use a lot of body products, you can skip this one.    

Wash Your Bathing Suits 

Make sure you clean and rinse your bathing suits before jumping into your hot tub.

Bathing suits that are fresh out of the dryer or washing machine will be filled with laundry detergents, so it’s better to rinse them with fresh water and let them dry before putting them on. 

Open the Hot Tub Cover

Opening your hot tub cover regularly will help prevent hot tub foam. In addition, the open cover will introduce oxygen, allowing the water to breathe and ensuring clear and clean hot tub water.

It’s also advisable to drain and clean your hot tub every three to four months to get rid of any solids that may have built up in the tub. 

How to Prevent Hot Tub Foam Naturally

If you don’t want to spend a lot of money on hot tub chemicals or want to add all-natural ingredients to the water, there are a few ways to prevent foamy hot tub water naturally. 

While these remedies can prevent foamy water, ensure you don’t use them as substitutes for actual hot tub chemicals. Also, all-natural ingredients aren’t as powerful as the cleaning chemicals specifically formulated for hot tubs. 

If you want to get rid of foam chemicals and don’t have the right chemicals on hand, here are a few solutions you can try:

Baking Soda/Vinegar Mixture 

Mix vinegar and baking soda in a 10:1 ratio. This means that if you have a 500-gallon hot tub, you’ll need to make a five-gallon solution consisting of 10% baking soda and 90% vinegar.


If you don’t have baking soda on hand, you can just add vinegar. Simply pour the vinegar directly into your hot tub in a 10:1 ratio. You’ll need to add five gallons of vinegar to a 500-gallon hot tub. 

Drain the Water 

If the problem persists even after trying the two solutions above, completely drain the water and refill the tub with clean, contaminant-free water.

How to Change Your Hot Tub Filter

Regularly cleaning your filters and replacing them when necessary is essential for optimal hot tub performance and health. Luckily, today’s advanced hot tub filters come with easy-to-clean cartridges, making filter maintenance straightforward. 

To clean your hot tub filter, remove its cartridge and clear away all the debris accumulated between the pleats. It’s best to use a garden hose with a filter nozzle attachment to do this job. 

However, if you don’t own one, then a hose with a regular nozzle will work just fine. Once clean, let the filter dry before putting it back in your hot tub. 

If you want to replace your hot tub filter completely, consult your hot tub’s user manual, as the process varies with each model. 

How Often Should You Change the Filter?

Swim spa filters

It’s best to clean the filter every couple of weeks to remove debris and prevent foamy water. It’s also advisable to clean the filter using a chemical rinse every month or so.

Simply spray the solution onto your filter, let it sit for around 15 minutes, and then thoroughly rinse with water. 

Make sure you do a chemical soak every few months as well. Add diluted filter chemicals to a bucket and place the hot tub filter in the bucket for around 24 hours. Then, thoroughly rinse the filter and leave it out to dry before placing it back in your hot tub. 

Change your hot tub filter after every two to three years, depending on your usage and any visible wear. 

Leave a Comment