It’s inevitable. At some point during hot tub ownership, your water will become old, dirty, or unbalanced. This leads to undesirable reactions in the water that cause it to look cloudy, foamy, or discolored. The first key to solving any problem is to understand what it is. With that in mind, we will go through the potential causes of these issues, outline some of the visual and textural properties of cloudy, milky, and foamy hot tub water to help you achieve an accurate diagnosis, teach you how to fix those problems if you have them, and how to prevent them. 

What is Foamy Hot Tub Water?

Foamy hot tub water describes a foamy type of film that can develop on the surface of the hot tub water. Unlike cloudy and milky water, it is much easier to pinpoint the cause of this issue.

What Causes Foamy Water?

Foamy water is caused by excess buildup of nonorganic matter in your hot tub. Simply put, products like lotions, soaps, sunscreen, makeup, and body sprays dissolve into the hot tub and build up over time. When they do, they create a foamy film that sits on top of the water that can leave residue on the shell around the water line

How Do You Fix Foamy Water

1. Treat the Cause, Not the Symptoms

We know the cause of foamy water is nonorganic matter buildup. This is largely preventable. By developing a clean usage routine, such as showering, removing makeup, or spraying yourself down, you can eliminate most pollutants before they ever reach the hot tub. It is important to not only develop this routine for yourself, but to make sure any guests adhere to it as well. Especially if they are frequent guests.

2. Shock the Water

Apply shock to the water. This will oxidize the foam and allow it to flow through your filter. Be sure to clean your filter thoroughly after this process as there will likely be some inevitable buildup.

3. Use a Defoaming Product

If that doesn’t work, you could try adding a defoaming product like SpaBoss Defoamer. This will work quickly but should be viewed as a short-term option since it doesn’t actually prevent the foam from coming back.

4. Drain, Clean, and Refill your Hot Tub

If all else fails it may be time to cut your losses and drain the hot tub. Before doing so however, we recommend using a spa purge product like Water’s Choice™ Clean & Drain. When used as directed, this product will help get gunk out of your spa’s plumbing, ensuring you start over with fresh, clean water. Once the hot tub is drained, you can take this opportunity to thoroughly clean it and check components, ensuring everything is running smoothly.

What is Cloudy Hot Tub Water?

When someone says they have cloudy hot tub water, it just means that it appears generally hazy and not in reference to anything specific. It looks like something could be in the water, but the particles are too small and diluted to touch or feel. The particles may also look like (or could possibly be) a huge cluster of tiny bubbles floating around in the water. There is no single cause of this issue, and you will see this to be a recurring phenomenon in different water issues.

What is Milky Hot Tub Water?

Metaphorically speaking milky hot tub water is just like cloudy hot tub water but with the volume turned up. The particles look similar but are much more densely populated, causing the water to have a milky and opaque appearance. Similar to cloudy hot tub water, there are a variety of potential causes.

What Causes Cloudy or Milky Hot Tub Water?

There are quite a few different and common causes of cloudy milky hot tub water. While causes may vary, the treatment stays relatively uniform. Let’s look at the potential causes and treatments below

1. Heavy Use Of The Hot Tub 

A common cause of cloudy hot tub water is heavy usage. The more you use your hot tub, the more contaminants you introduce to the water chemistry. This is especially true after a hot tub party.

2. Pollutants In The Air

Many pollutants and organic debris such as pollen, dust, and insects float around in the air. Eventually, may find their way into your water. Over time, they can build up and cause or contribute to water issues.

3. Bacteria And Algae

The warm water in your hot tub is a perfect breeding ground for algae and bacteria. Not only can bacteria growth cause cloudy or unclear water., but bacterial growth can also cause severe skin irritations.

4. Chemical Imbalance

To ensure the clarity of your hot tub water, you must maintain the correct water balance. Do this by using the right chemicals to balance the water chemistry. Keeping an ideal sanitizer level is a cornerstone of basic hot tub chemistry and will help maintain water that is safe, clean, and clear. Unbalanced water can result in staining, scale build-up, and green, foamy, or cloudy water.

5. Poor Functioning Filtration System

Filtration systems can consist of more components than just the filter.

6. Body Care Skin Products

When you use a hot tub, non-organic substances on your body and clothes will dissolve into the water. Products such as body oils, makeup, hair conditioners, and lotions affect the water quality and can cause it to appear cloudy, milky, or foamy.

7. Metals In The Water

Cloudy or milky water can be a strong indicator of contaminants such as metals. If you aren’t using a pre-filter when filling your tub, this is a prime way for metals to enter your tub. This is especially true if you use a well or water directly from the city. While many cities do have water treatment facilities, the quality and effectiveness of those facilities can vary widely.

8. Poor Water Care

Proper water care is a foundational block to successful hot tub ownership. Using incorrect, low-quality chemicals, using them at improper dosages, failing to maintain proper levels, and many other water care issues can also lead to milky or cloudy water.

9. Air In The System

Tiny air bubbles can make their way into your water in various ways. Depending on the source and the amount, these can cause the water to look hazy or even a little milky.

10. Poor Circulation

Water doesn’t like to be stationary. It loves to move and flow. This helps the water in a number of ways including maintaining balanced water chemistry. By regularly keeping your water in circulation, it makes it much harder for bacteria to form. Letting your water sit for long periods of time will allow bacteria to multiply at a rate that only increases over time. This is just another reason to use your hot tub more often.

How Do You Clear Up Cloudy or Milky Water in The Hot Tub?

1. Check Water Alkalinity, pH, And Sanitizer Levels

You can test your water using test strips or drop-style kits. The core levels should be as follows:

80 – 120 ppm

 7.2 – 7.4

Chlorine 1-3 ppm

Alkalinity levels are what keep the pH stable and must always be adjusted prior to adjusting the pH. If the pH is high, adjust alkalinity to 120-150ppm. When you add pH Reducer to decrease the pH level, alkalinity will drop to the recommended range of 80-120ppm. 

2. Shock Treatment

Shock the water using non-chlorine shock to oxidize contaminants so they can be picked up by the tub’s filtration system.

3. Check And Clean The Filters

A good rule of thumb is to hose down your filters once a week, and clean with a chemical cleaner once per month. Always be sure to check for stuck or torn pleats.

For more information, here is a step-by-step guide to filter maintenance

4. Get Some Help

Water care should be simple once you get it dialed in. If you are having trouble maintaining proper balance and cleanliness, reach out to the friendly and knowledgeable staff at Great Bay Spa & Sauna. We will be more than happy to listen to your issues and develop a customized plan that will suit your specific needs

5. If Nothing Else Works, Drain And Refill The Hot Tub

Sometimes the juice isn’t worth the squeeze. If you find yourself in a no-win situation, or your hot tub water has reached its full lifespan, it is best to start fresh. Use Water’s Choice™ Clean & Drain to help clean out your spa plumbing, then drain and clean the tub, and start over with clean, filtered water.

How Can I Prevent Cloudy, Milky, and Foamy Water in My Hot Tub?

Use Clean And Filtered Water

If you use clean water that has been carefully filtered, this is the first thing you should do. Installing a hose pre-filter will help to keep the water clean when you fill your hot tub.

Check For Dirty Filters And Clean Them Regularly

A clean filter keeps the hot tub’s water clear and clean by preventing scale or any slimy substance from building up. Always follow a regular maintenance schedule that includes checking the filter, rinsing the filter every week, cleaning the water filter every month, and replacing it whenever necessary. If you notice any tears or the filter pleats are stuck together, it’s time to replace the filter.

For more information on filter maintenance, check out our step-by-step guide to properly cleaning your filter.

Make Sure The Chemical Balance Of Your Hot Tub Is Right

You should check the hot tub’s chemical levels regularly. You must monitor alkalinity, pH, sanitizer, and calcium levels. If necessary, adjust them. By being proactive and keeping your water balanced, you reduce the risk of cloudy water.

Stick To A Regular Maintenance Schedule

Prevention of many water care issues starts with a proper maintenance schedule. This will ensure all elements of the hot tub are working at their peak ability, allowing you to change them right away if they’re not. 

For more information on what a good maintenance schedule looks like, here are some Key Maintenance Tips Every Hot Tub Owner Should Know 

Drain The Hot Tub And Replace The Hot Tub Water

Every three months to 6 months, apply Water’s Choice™ Clean & Drain to the tub, drain and clean it, and then refill it. This is also a great time to clean or replace your filter.

Use a Quality Hot Tub Cover

Using a hot tub cover will prevent airborne debris, particles, and other contaminants from falling into the water. Making sure the cover is high quality will not only give you peace of mind but it can also help increase the life of your hot tub. 


Proper maintenance, water care, and regular use of your hot tub will fix and prevent the majority of issues hot tub owners face. While that sounds so simple, we understand how difficult it can be at times, especially for new owners. If you are testing your hot tub water more than once a week, struggling to keep your water balanced, or have any other questions, please stop by Great Bay Spa & Sauna for a free water test and personalized advice.