Hot Tub Water Cloudy and Smelly? Here’s How to Fix It!

There’s nothing worse than coming home after a long day of work, wanting to soak in your hot tub, only to find the hot tub water cloudy and smelly.

I’ve dealt with this before, and here’s what I know:

Cloudy or smelly hot tub water can be caused by high pH, low sanitizer, or a build-up of scum and/or bacteria in the plumbing of your hot tub known as biofilm. To clear the water, add a double-dose of chlorine-based shock, rinse the filters, and ensure pH and alkalinity levels are within range.

But that only scratches the surface of both the potential problems and solutions. So let’s keep going!

In this article, we’re diving deep into the world of smelly and cloudy hot tubs. We’ll examine all the possible causes. But more importantly, how you can fix it quickly and easily and get back to soaking.

Cloudy and/or smelly hot tub water is a sign that something is wrong, and needs to be fixed before you can use your hot tub.

If you haven’t fully mastered the proper chemical balance and maintenance required for a hot tub, you may see or smell something wrong. Don’t fret, you can easily fix these issues and get back to soaking in no time!

Why is my hot tub water cloudy, smelly, or foamy?

As you head into your hot tub after a long day of work, the last thing you want to see or smell is cloudy or foamy water, coupled with a foul odor. I’m sure you’re asking yourself, how does this happen and what do you do?

The cloudiness of your water can be due to any number of things. These include:

  • Frequent usage
  • Dead algae
  • Poor filtration
  • Organic debris
  • Poor water chemistry

You should check all of your chemical levels.

If the levels are off, then that could cause cloudy or foamy water. You will want to correct any imbalance with the pH levels and your sanitizer.

Use a chemical test kit to check the pH levels. Water with a pH level that is greater than 7.8 ppm (parts per million) has too much pH in it.

Additionally, if your water’s alkaline levels are higher than 120, it is too alkaline. Either of these issues, high alkalinity or high pH, can cause cloudy water. High pH can also be the cause behind hot tub foam.

The foam that appears in hot tubs is not harmful. It is simply a buildup of products and Total Dissolved Solids (TDS) in the hot tub’s water. Hot tub foam is caused by “full” or old water.

Several different products can cause hot tub foam if added to the water.

These include:

  • Soap
  • Laundry detergent
  • Makeup
  • Cosmetics
  • Deodorant
  • Body lotions
  • Shampoo
  • Conditioner
  • Body oils

Even though the foam is not harmful, it’s not recommended to soak in.

In fact, you should never enter a hot tub with foam, it is a clear indicator that the sanitation is not being properly maintained.

Additionally, low calcium levels (the hardness of the water) in your spa can decrease the surface tension of your spa’s water, which in turn allows for excessive foaming on the water.

Low calcium levels in your water can damage your hot tub in other ways too.

Biofilm can be another cause of cloudy or smelly water

Biofilm is exactly what it sounds like.

It’s the residue of stuff (a combination of everything listed in the list above) that ends up drifting into your hot tub pipes and clinging to the insides of them. You won’t see it, and it won’t be caught like regular debris by the filter. But the odor is there, ruining your experience in the hot tub

But a bad-smelling hot tub is a sign unwanted bacteria is in your hot tub water.

Because hot tubs are moist, warm, and humid, they are a great breeding ground for bacteria. Keeping properly balanced water chemistry is the key to avoid this issue.

You should test the water regularly, adjusting the chemical levels when necessary.

When your hot tub’s pH is too low, it is usually accompanied by a sharp, pungent smell. When the pH level of your hot tub is too high, it is usually accompanied by a musty, stale odor.

If you want to know more about foamy water in your hot tub, what causes it, AND how to get rid of it, check out this recent article. What really surprised me was how the frequency that you change your water significantly impacts foam.

Just click that link to read it on my site.

How do I clear up cloudy water in my hot tub?

To clear cloudy hot tub water:

  • Rinse the filters, replacing if older than 18 months
  • Check the pH and alkalinity levels and adjust as needed
  • Add a double-dose of chlorine-based shock
  • Add hot tub clarifier which binds particles in the water and enables them to be better trapped in the filter

Let’s examine some of these in greater detail:

First, you should check your filter when you see cloudy water.

Filters should be replaced or cleaned regularly. Body oils, soap, detergent, sweat, and other matter trapped by hot tub filters need to be broken down with a solvent. Filters should be cleaned thoroughly, at the very least every month.

Hot tub filters, however, don’t last forever.

Not sure how often to replace yours? It isn’t just a set number for everyone. After all, different people maintain their water regularly and clean their filters regularly. Others just don’t stay on top of it.

But to gauge how often you should change yours, check out this recent article. I walk you through all the steps of figure out when to change yours, how to do it, and some best practices for keeping them clean in between changes.

Just click that link to read it on my site.

Hot tub clarifier

This simply causes all the tiny particles of dirt, debris, and oils to be combined so they are large enough to get caught in the filters. Left alone, they are often so small they pass right through the filters.

Add up to 8 oz. to clear the water now, and then add a small amount each week to maintain it.

CLICK HERE to see my favorite clarifier on Amazon.

Second, add sanitizer after every use of your hot tub.

This helps prevent bacteria from growing, which causes cloudy water. When you get out of the hot tub after every use, the water is always dirty.

Some sanitizers are bromine, while others are chlorine.

Not sure which is best or if you can switch back and forth? Luckily, I break down all the pros and cons in a recent article.  I review all the things you need to know to make the right decision for you.

One is more pocket friendly while the other requires less frequent use. So pick the one that’s right for you.

Just click that link to read it on my site.

Additionally, always make sure you check your pH levels.

An imbalanced pH level can cause cloudy water.

Check the pH level by using test strips, and ensure it is between 7.2-7.8 parts per million.

Now, sometimes people get confused by pH and alkalinity. Or they think they are the same things. In fact, while related, they are totally different. And sometimes you may need to raise one but not the other.

Luckily, I break it all down in very simple terms in a recent article.

I make it easy to see the differences and how to treat each one individually. But I also get into how they relate and interact with each other.

Just click that link to read it on my site.

Gimme gimme shock treatment

Shocking your water can stop algae and other unwanted bacteria, in addition to fixing cloudy water. Shocking your water is done weekly in most cases.  It helps the sanitizer do its job. But more importantly, it restores the chlorine or bromine levels to their proper PPM.

Ironically, poorly shocked water can often show normal levels of chlorine or bromine while actually not having any at all.

Check out this recent article if you want to learn more about shock for hot tubs. I cover what it is, different types, and how to gauge when it’s time to add some.

Just click that link to read it on my site.

As a last resort, you can also simply drain the water in your hot tub and replace it with fresh water. Be sure to add the correct chemical levels.

How do I stop my hot tub from smelling?

Stop a hot tub from smelling by adding a double-dose of chlorine-based shock, and allow to circulate with the jets on and cover off for 20 minutes. Additionally, check pH and alkalinity levels and rinse off or replace the filters.

A smelly hot tub is more common than you think.

The first thing to do is to move your hot tub’s cover away from your hot tub. Hot tub covers, especially after many years of use, can accumulate debris and other matter. This leads to them smelling bad.

That’s especially true if your cover gets tears and becomes waterlogged as that can lead to mildew inside the cover.

Move the hot tub cover away from your hot tub, and determine if the smell is coming from it. If it is, this will save you the time of playing and balancing with the chemical levels. To remedy a cover issue, simply clean the cover thoroughly and put it back on.

If it turns out your water is the culprit of the bad smell, here’s what you should do.


The first step in decontaminating unbalanced and smelly water is to hyper-chlorinate the water.

This will give your water an extra dose of sanitizer to help kill the bacteria in it. To hyper-chlorinate, bring the chlorine level in your spa to at least 100 parts per million. Use granular chlorine to do this.

Pre dissolve the chlorine granules in a five-gallon bucket.

This is so the rough granules don’t damage the acrylic surface of your hot tub. Add the chlorine and then circulate the water at high speed for a half an hour with the cover closed and all jets turned on. This will ensure maximum circulation.

After you’ve done this, leave the hot tub cover off for a few hours.

This will allow the gases to escape. You should only do this when you know it will not rain or be windy. This is because you do not want debris to fly into your hot tubs water, ruining the chemical balance you just fixed.

If you do all this and the smell continues, consider draining your hot tub entirely.

After circulating the hyper-chlorinated water, add an item like Oh Yuk Healthy Hot Tub Cleaner (click to see the current price on Amazon) to your water.

This is the best product I’ve found to clean out any build up in your plumbing, jets, or filtration system. After completing the clean, you’ll empty your spa water and completely refill.

If you decide to empty your spa completely and replace the water, begin to adjust the chemistry of the freshwater immediately.

Ensure that both the alkalinity and pH levels are balanced. Once it is balanced, add the pre-dissolved granular chlorine, ensuring the level reaches ten parts per million. Then allow the water to circulate for ten to twelve hours.

Test your water, and when it comes back with a reading that shows successful decontamination, continue by balancing your water with your sanitizer of choice and be sure to maintain all other levels.

How do I keep my hot tub water crystal clear?

Crystal clear hot tub water is best obtained by:

  • Check and adjust pH and alkalinity weekly
  • Add chlorine sanitizer every 2-3 days
  • Or add bromine sanitizer every 4-5 days
  • Add chlorine-based shock every 7 days
  • Rinse the filters every 3 weeks
  • Deep clean the filters every 3 months
  • Replace the filters every 12-24 months

Additionally, you can also ask guests to shower off before entering the tub.

First of all, you must use a hot tub cover! It’s simple and very easy, but it blocks debris that can fall into your hot tub. If you have debris in your hot tub, use a debris remover such as a skimmer to remove leaves and twigs.

Hot tub covers are pretty routine with portable (above-ground) hot tubs. But they are less common with in-ground hot tubs. But they are essential.

Another way to keep your water crystal clear is to have anyone who is about to soak in the hot tub take a shower beforehand.

But checking the pH of your hot tub water must be done religiously.

The pH of your hot tub water should be between 7.2 and 7.8 parts per million. Anything above 7.8 is considered bad. This can cause cloudiness in your water.

To keep it clear, check the water in your hot tub at least once a week if you are a light user, and 2 or 3 times weekly if you use your hot tub heavily.

Also, ensure you sanitize your water regularly.

Next, you should replace your hot tub water every 3-6 months. Once you drain your hot tub, clean it thoroughly before replacing the water. I like to use Oh Yuk Healthy Hot Tub Cleaner (click to see the current price on Amazon) EVERY time I change my water.

That helps keep the build-up out of the pipes.

Not sure how often to change the water, why I give 3-6 month range or how I drain mine in just 15 minutes? Check out this recent article.

I break down everything you need to know about changing your water. Just click that link to read it on my site.

Additionally, make sure the filters in your hot tub are clean.

If not, you need to clean or replace them if you want crystal clear water. You can clean your hot tub filters by rinsing it with hose water.

You can also do a chemical soak with a filter cleaner solution diluted in water. Soak the filter for 24 hours in the solution. After the 24-hour soak, rinse it with water to get the cleaning solution out of your filters before you reinstall them.

Contaminants can cause your hot tub water to become cloudy over time as they build up.

Things like:

  • Body oil
  • Sweat
  • Dirt
  • Suntan lotion
  • Soap
  • Deodorant
  • Shampoo
  • Conditioner
  • Makeup
  • Laundry detergent 

Additionally, wearing shower caps while soaking in your hot tub will ensure hair and hair products do not enter the water.

Can too much chlorine cause cloudy water?

Too much chlorine can make hot tub or pool water cloudy. For this reason, add small amounts of chemicals and add more if needed. And always test the levels before adding chemicals.

In fact, any imbalance in the hot tub water chemicals can cause hot tub water to turn cloudy. In addition to too much chlorine or bromine, this also includes high pH, high calcium hardness, and high alkalinity.

When too much chlorine is added to the water, calcium can solidify into calcium carbonate. The calcium carbonate can cause the water to cloud.

The easiest way to know if you have too much chlorine is to use a water testing kit to test the chemical levels in your hot tub. The ideal reading for free chlorine is one to three parts per million.

Anything higher means your chlorine is imbalanced.

Is a cloudy hot tub safe?

Cloudy water in a hot tub is not safe as it indicates a chemical imbalance either with sanitizer or pH or alkalinity. Test the water and adjust as needed. Circulate the water with the jets on and cover off for 20 minutes. Then test again. Only enter when the levels are within the normal tolerance.

Your hot tub should be crystal clear when you go to use it. It should not be full of cloudy water you can hardly see-through.

When the water in your hot tub is cloudy, it means there is an issue.

The cloudy water can be caused by several things, including bacterial growth, chemical imbalance (high or low pH, etc), or a problem with your hot tubs water circulation.

But when the water is cloudy, it can indicate bacteria growth or other unsafe conditions.

How long does it take for cloudy hot tub water to clear?

Hot tub water can take up to 24 hours to clear up when it is cloudy. Adding a hot tub clarifier and ensuring pH and alkalinity levels are normal can see clearer results within 30 minutes.

CLICK HERE to see my favorite clarifier on Amazon.

So it really depends on your method of getting rid of it, and how bad it is, to begin with. 

But in most cases, if it’s not a situation where you’re having to drain the water, most minor chemical imbalances can be corrected within 30 minutes.

Just test the water. Adjust as needed and run the jets.  Test again in 30 minutes. If you adjusted correctly, the water should now be balanced, clearer, and not smelly.

If so, the water is good to get in!

Did I cover all you wanted to know about cloudy and smelly hot tub water?

Foam, cloudiness, and a bad smell in hot tubs and spas are problems encountered by almost every spa owner at some point in time. Don’t worry, you can easily fix these issues!

The cloudiness of your water can be due to any number of things. These include frequent usage, dead algae, poor filtration, poor water chemistry, and organic debris.

You should check all of your chemical levels to ensure there is no chemical imbalance.

If the levels are off, then that could cause cloudy or foamy water. You will want to correct any imbalance you find. Use a chemical test kit to check the pH levels. Water with a pH level that is greater than 7.8 ppm (parts per million) has too much pH in it.

To clear up foamy or cloudy water, check your chemical levels including pH and alkalinity. Balance these levels if necessary. Ensure your filter is clean. If not, replace or clean it. If you have to, shock your water.

Finally, as a last resort, completely replace your hot tub water and clean the pipes and filter. All of these different steps will also help combat a smelly hot tub.

Ever struggled with an awful rash when you get out of the hot tub?

Even if you haven’t, I bet there are times when your skin is red, itchy, or irritated after getting out. If that sounds familiar, you might be surprised to know that not all hot tub chemicals are the same.

And some of them aren’t even really necessary for most hot tub owners.

Check out my recent article where I break down the best chemicals to buy, especially for sensitive skin. I get into the best brands, what products to avoid, and how to treat your water.

Just click that link to read it on my site.

Photos which require attribution:

Hot tub! by eileenmak is licensed under CC2.0

Jeff Campbell

Jeff Campbell is a husband, father, martial artist, budget-master, Disney-addict, musician, hot tub lover, and recovering foodie having spent over 2 decades as a leader for Whole Foods Market.

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