Is Your Hot Tub Foaming? Here’s What to Do

Plenty of people love bubble baths and long soaks in bubbly water. However, a layer of bubbles or foam in your hot tub is not a good sign. Since a spa functions different from a bathtub, foam in your spa water indicates a problem and could cause more issues if the foam gets into your pipes and pumps.

A foaming hot tub indicates the water is contaminated or something in the filtration system is not working properly. What’s causing your spa to fill up with scummy bubbles? Let’s find out by looking at several common factors that can contribute to foamy hot tub water.

A thick layer of foam or bubbles on top of your hot tub means there’s likely a problem with the water. Here’s how to get things back to normal. #SpasUnlimited Share on X

What Causes Foamy Hot Tub Water?

The cause of your bubbling water determines the solution. If your hot tub sees frequent usage, the most likely culprit is a buildup of contaminants in your water. These contaminants might include lotion, makeup, body oils, deodorant, or even laundry detergent from the last time you washed your swimsuit. If you use your hot tub on a regular basis and don’t change the water more frequently to compensate, these contaminants can build up in your hot tub and churn into foam.

Another potential cause of foaming water is bacterial buildup, also known as biofilm. Bacteria growing in your hot tub will cause any sanitizer you added to be used up quickly, causing contaminants in your water to form bubbles much sooner. In addition to causing foam, biofilm is simply unpleasant in general and bacterial growth has the potential to make you sick.

Finally, another common cause of hot tub foam is a poor chemical balance. A less than ideal combination of spa chemicals won’t break down the contaminants that can create foam. Without this protection, preventing foam is difficult if your spa sees regular usage.

Get Rid of Hot Tub Foam

Begin by determining what’s causing your hot tub to foam. Test the levels of chemicals and sanitizer in your water and add more of each as needed to restore proper levels. Low levels of general hot tub chemicals are easily restored–just add more and make sure they stay at the proper level. However, if the sanitizer levels have plummeted again within a day or two, you’re probably dealing with a buildup of biofilm. Buy antibacterial hot tub cleaner and let it cycle through your piping system several times before replacing the water.

If your chemical and sanitizer levels seem to be fine, but your hot tub is still covered in a layer of oily bubbles and forming a ring around the edge, your water is contaminated. You have two options for getting rid of contaminant foam. For a faster solution, simply drain the water, scrub the hot tub shell, and refill your spa with clean water. If you don’t mind waiting a few days, add an oil-absorbent sponge to the water and allow it to soak up the contaminants.

Pro Tip: Anti-foam chemicals for your spa are only a temporary solution and don’t actually clean your water. Use sanitizer or special cleaning products to get rid of the underlying problem.

Prevent Hot Tub Foam

Even if you’re dealing with bacterial buildup or a chemical imbalance, the ultimate cause of foamy hot tub water is contaminants and residue. Consequently, the easiest way to prevent foam from returning is to control how many contaminants make it into your spa. Shower before soaking to remove sweat, makeup, lotion, or other primary offenders that could gunk up your water, and make sure your swimsuit is thoroughly rinsed to remove all traces of soap residue. Try to keep future contaminants to a minimum. Most importantly, if you suspect your hot tub is developing an oily layer on the water again, use another sponge or replace the water entirely.

A Foam-Free Hot Tub Experience

Few things are more uncomfortable than feeling more oily after leaving your hot tub than when you went in. If you notice foam starting to form in your spa, don’t wait for it to get out of hand! Find and treat the problem quickly to preserve a comfortable experience and prevent your hot tub from foaming. Not only will your water feel more pleasant, but it will also look more appealing than a layer of thick foam.

Join the conversation to learn more about preventive hot tub maintenance and cleaning.