When Fizzy Hot Tub Water Is a Bad Sign (and How to Fix It)

Jennifer Rhodes

By Jennifer Rhodes · Updated

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Your hot tub should ideally be a place where you can unwind and relax. Unfortunately, a sensation of fizz can make it feel more like a bottle of champagne than a peaceful spa. What causes a hot tub to feel fizzy?

Generally, fizzy hot tub water indicates that your water is old or has a chemical imbalance. Over time, this might make the water smell sour, appear cloudy, and irritate your skin. However, fizz can also be a perfectly normal byproduct of the gases in your tub's pressure jets.

Thankfully, there are ways to prevent effervescence and keep your tub's water crystal clear.

What causes fizzy hot tub water?

Your spa's water might get fizzy for a few different reasons. Most of the time, draining, cleaning, and refilling your tub can fix the problem. However, there are cases when these bubbles are unavoidable.

Here are the main causes of fizzy hot tub water:

  • pH imbalance: Your tub may effervesce if it's too alkaline or acidic. It's crucial to fix this problem immediately since acidic water corrodes your spa's plumbing. So try to test your water's pH at least twice weekly.
  • Cosmetics: Makeup and hair products often contain chemicals that can fizz in water. To prevent this, consider showering before you use the spa.
  • Cleaning products: The shampoos and detergents you use (or have left in your swimsuit) may react the circulation your spa's water. In many cases, this mixing results in effervescence.
  • Dirty filter: Contaminated filters can cause fizzing or even discoloration in your tub. As a result, ensure that you clean them regularly and replace them annually.
  • Pressure jets: Gases from your tub's pressure jets may cause a fizzy, cloudy effect in the water. These bubbles are expected and should dissipate after you turn the jets off.

When is fizzy hot tub water bad?

So, you can see there are several potential causes for fizzy spa water. And unfortunately, some of them can be detrimental to your health and hot tub.

pH imbalance

For example, one of the most common sources of effervescence is unbalanced pH levels. Overly acidic water may not only fizz, but also irritate your eyes and skin. Plus, it can corrode your spa's plumbing over time.

Similarly, a hot tub that is too alkaline may appear cloudy and greenish. So to avoid the above problems, ensure you regularly test and balance your spa's pH levels.


Introducing either detergents or bacteria to a hot tub are generally both bad news. They can both create undesirable environments in a hot tub.

One troublesome culprit when it comes to bacteria (assuming your sanitizer looks fine) is the filter. Old filters often get clogged up with mildew and sediments, producing a fizzy foam. And your hot tub may become contaminated with bacteria and algae as a byproduct.

When is fizzy hot tub water normal?

If none of these things seem to be the problem, keep in mind that some effervescence is totally expected and safe, and is just a normal part of the spa operating.

If your water is balanced, there's no foam, and your tub is otherwise clean, the bubbles are most likely nothing to worry about.

The jets on your tub, as an example, naturally produce fizz from dissolved gases. And these intentional bubbles make your spa's water feel fresher, crisper, and more relaxing.

How to fix fizzy hot tub water

If your hot tub is fizzy due to one of the undesirable reasons, don't worry—there are several ways to fix and prevent this common issue.

Here are some tips on getting rid of the fizz:

  • Shower before you soak: Take a quick rinse without cleaning products before you hop in your hot tub. Doing so helps wash away any dirt, detergents, and hair products that could cause fizzing.
  • Rinse your clothes: Bathing suits fresh out of the dryer may still carry detergent. To avoid any fizz, quickly rinse off anything you intend to wear in your spa. If you have a secluded yard, going naked is also an option!
  • Chemical balancing: Use testing strips to check your hot tub's water, at least twice a week. You may only need to adjust the chemical balance to fix the fizziness.
  • Filter maintenance: Remove and rinse your hot tub's filter every 2 weeks. Keeping it clean will make effervescence less likely. You should also get a new filter every year.
  • Draining: pH and chemical imbalances are more prevalent in older hot tub water, as water becomes harder to balance over time. If all else fails, it's probably time to drain and start over. Try to repeat this process every 3 to 4 months.

Other problems to look out for if you notice fizzy water

There are other issues related to fizziness that you may also notice. Knowing the signs can help you prevent them, keeping your hot tub as crystal clear as possible.

Below are other problems which could be linked to the same causes as fizzy water:

  • Foam: If left untreated, water that starts fizzy may eventually become foamy. Generally, this issue indicates that your spa needs more sanitizer.
  • Cloudiness: Cloudy white water often accompanies effervescence in hot tubs. Dirty filters and high pH are the most common culprits behind this haze. But a cloudy spa may also indicate that your water is too old and needs replacing.
  • Discoloration: Does your water look green or brownish? If so, you likely have an algae problem. If you add chemicals to fix this problem, your water may temporarily fizz.
  • Odor: Fizzy water may come with a musty stench. And typically, that means you have a bacterial problem and should sanitize your spa. If the stench remains, consider draining and refilling your tub.

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