Why Does My Hot Tub Foam?

Hot tubs are a great way of taking some time to yourself, or relaxing with friends after a hard day.

We all love to chill out and relax in the hot tub sometimes. You can sit back, release your muscles and let the bubbles work their magic.

But have you ever gone in a hot tub and the water looks foamy, murky or milky? Gross! No one wants to sit in so much hot tub foam that it looks like you just emptied a bottle of bubble bath just like when you were a kid. 

However, without knowing what causes this foamy fiasco, you will never be able to fix it! So, why does your hot tub foam so much?

Why does my hot tub foam?

Having a foamy hot tub is a common occurrence, and is typically nothing to be worried too much about.

Generally speaking, the foam in your hot tub will just be a build up of products, oils and any other particles within the water. 

This is usually caused by excessive use of the water because things like make up, skin cells, deodorant, soaps, laundry detergent, drinks and many other things have come in contact with the water, and will tend to build up after multiple uses of the hot tub. 

If your hot tub is foaming a lot, then it typically just means that the water has become old or used, and the action of turning the jets on in the water will create the foamy reaction. 

In addition, you may have a lot of foam in your hot tub water when using it because of low calcium levels in the water. This means that you may have soft water in your hot tub.

We always recommend that you do not use soft water in your hot tub as it may eventually damage your hot tub or spa equipment after excessive use. 

Having soft water or water with low calcium in your hot tub will highly increase the foaminess in your water, and so you should always try to maintain the correct calcium level or hardness in your water. This can be done by repeatedly checking the hot tub and adjusting the levels if needed. 

If you have a hot tub, then you already know how much upkeep it takes to keep the water healthy and safe.

You have to stay on top of chlorine and heat levels to keep the water balanced perfectly and ready to be used. 


To ensure that your hot tub water is safe, and reduce the risk of foaming, then you will have to make sure that your water is balanced.

Unbalanced water can be unsanitary, give off bad odors or even discolor, which is not very inviting to say the least!

You will also need to keep checking on your hot tub to ensure that the pH levels are correct, the calcium levels are okay, and the water is sanitized and safe for use. 

How to avoid foamy water in your hot tub

For the best results, and to keep your hot tub water healthier for longer, you will want to shower before and after using the hot tub.

This is to ensure that all creams, lotions, oils, perfumes and sunscreen is completely off your skin and will not mix in with the hot tub water when you use the tub.

This will mean that your body is clean of sweat, dirt and lotions that would later mix in with the hot tub and cause a build up of dirt and grime that could result in the foaminess that we have all come to dislike. 

We know that this sounds like a great inconvenience when you just want to kick back and chill in the hot tub after work, but it keeps your tub working properly for longer and without any foam. 

In addition, you will need to ensure that your swimsuits are clean before entering the hot tub for the same reasons. Laundry detergents can also cause a build up in your hot tub water and change its levels. 

We also recommend that you use only the best chemicals and sanitizers to keep your hot tub water fresher for longer.

Cheaper ingredients tend to be less strong than reliable chemicals, and you will have to spend much more time checking and balancing your water’s pH levels. 

You can also open up your hot tub every now and again (if it has a cover) in order to let the water breathe.

Leaving the lid open exposes the hot tub water to fresh air, and sunlight, which will introduce some oxygen into the hot tub. 

If that still does not work, then you should try to shock your hot tub regularly. This can be done with a chlorine hot tub or spa shock product that works to flush out bacteria and break down the build up of microorganisms or products.

Try using a powerful chlorine spa shock such as SpaGuard Enhanced Spa Shock 6#.

To keep on top of the safety and cleanliness of your water, we recommend that you shock your hot tub on a weekly basis!

Finally, if that foam simply persists, then it is probably time to replace the water in your hot tub. You will have to drain the hot tub of all of the water, build up and grime, and refill again.

Do not forget that you will still have to check the pH level and chlorine in your water before using for best results. 

You should always check your hot tub water with test strips before using, such as these ones for example: Leisure Time 45010A Test Strips Chemical Tester for Spas and Hot Tubs.

Most of the time, if you already have foamy water in your hot tub, then it is best to simply grin and bear it, and start emptying the tub. It will be worth it, because once it has filled back up, you can enjoy the crystal clear water and comforting jets without the foam!