How To Remove And Prevent White Water Mold In A Pool

When mold gets in your swimming pool, it can majorly detract from summertime entertainment. How do you clear your pool of white water mold so you can begin having others over to enjoy the pool again?

To remove white water mold, shock the pool, clean the filter, balance the pH, brush the mold away, and run your pump longer. Many of these methods come in handy for preventing the recurrence of pool mold as well.

In this informative guide, you’ll learn what white water mold is, how to identify it, what causes it, how dangerous it may be, how to remove it, and how to prevent it. If you own a pool, then you can’t miss this article.

white mold in water

What Is White Water Mold?

One type of mold that’s fairly common in swimming pools is white water mold.

This may be the first you’re hearing of it, so allow us to explain what white water mold is.

White water mold is a type of fungi just as all mold is. It’s a more naturally-occurring type of mold that forms in the water.

It’s not necessarily about how many pool chemicals you use or the lack thereof. Since white water mold is naturally occurring, it’s something that many swimming pool owners have to contend with at one point or another.

White water mold may develop on its lonesome or it may be accompanied by pink slime, which is also referred to as pink algae.

What Does White Water Mold Look Like?

Getting back to white water mold, how do you know that that’s what you have floating around in your swimming pool?

After all, at any given time, your pool could be filled with all sorts of contaminants, from leaves to dust and dirt, insects, twigs and branches, animal droppings, and even small live animals.

White mold doesn’t look like any of the above. It has an appearance like wet tissue in the water. The mold also resembles mucus, which is an unappealing similarity, but one that had to be made.

Admittedly, it can be somewhat difficult to detect white mold depending on how sunny of a day it is and what color your pool liner is.

Even the cleanliness of the pool–or lack thereof, in this case–can make your quest to find the mold more difficult.

Since white water mold can develop regardless of how clean and chemically treated your pool is, you should ideally look for it after you comb through the water with a skimmer or pool brush.

If you’re still having a hard time confirming the presence of white water mold, the accompanying pink slime that may form with it should be far easier to see.

What Causes White Water Mold in Pools?

To make it clear, the presence of white water mold does not denote a dirty pool.
It also doesn’t mean your pool is necessarily unbalanced, although a pH imbalance certainly doesn’t help matters.

Instead, to reiterate, white water mold occurs naturally, especially if you fill your swimming pool with water from the tap or a garden hose.

The plastic-adoring white water mold might already be present in the hose. When you place the garden hose in your pool to fill it up, you’re adding more than water, but mold as well.

Is White Water Mold Harmful to Humans?

On this blog, whenever we discuss mold, that often comes with a disclaimer about how it can worsen one’s health, especially for those with asthma or mold allergies.

However, white water mold does not come with the same disclaimer. It’s considered harmless.

That doesn’t mean you want to stick your face in it or inhale it, but it shouldn’t cause any ill effects during regular encounters.

While this may give you more leeway when you address your white water mold issue, you still don’t want to put it off forever.

Like any type of mold, white water mold can thrive and spread in suitable environments like your pool!

How to Remove White Water Mold from a Chlorine Pool

If you want to remove white water mold from your chlorine swimming pool, per the intro, here are some steps to follow to remediate the issue.

Clean the Pool Filter

If white water mold is lingering around on the surface of your pool, then you can bet it’s gotten into the pool filter as well.

Moreso than that, the fungi could be in your pool pipes, where it can spread.

Your filter can’t work when it’s gunked up with white water mold, so you’ll have to clean it.

Not all pool filters are the same. If yours is a diatomaceous earth or DE filter, you need to backwash your pool for about five minutes, then turn the pool pump off.

Next, open up the drain plug and allow the filter to fully drain, then take the manifold out of the filter tank. Now you can clean the tank itself.

You can use a garden hose for this. Be sure to clean the filter grids and the manifold as well.

If yours is a traditional cartridge pool filter, you again have to turn the pool filter and pump off and let the air out of the system.

Next, take the cartridge out of the filter and use a garden hose to rinse away debris and mold.

For sand pool filters, you can begin the cleaning process by backwashing the pool for five minutes. Next, power down the pool pump and choose the filter option.

Open up the pump lid and transfer the sand filter cleaner to the strainer basket. Run the pump in 15-second increments to send the cleaner through the sand filter, then give the pump an eight-hour break.

Finally, wrap up by backwashing for another five minutes.

Balance the pH

Before you shock your swimming pool, you should balance the pH levels. You want the levels to be no lower than 7.2 and no higher than 7.6. You’re aiming for 7.4 on the pH scale.

Shock Dose the Pool

Once the pool filter is free and clear of mold and the pH balanced, it’s time to treat the water in the pool.

You’ll need to shock the pool with chlorine shock or calcium hypochlorite for that.

Shocking the pool simply refers to adding more chlorine than usual. What this does is dramatically increase the level of chemicals in the water to kill fungi and bacteria.

You want to use at least three or four pounds of shock for every 10,000 gallons of pool water to kill stubborn white water mold.

This is much more chlorine than you’ll use when regularly shocking the pool, as that’s only one pound for every 10,000 gallons of pool water.

Keep testing for bromine and chlorine levels in between shocking.

Use Your Pool Brush

You’ve removed most of the white water mold at this point, but it could still be lingering around pool surfaces such as the pool liner, the ladder, the return jets, and the deck.

If brushing on concrete or plastic, you need a pool brush with steel bristles. For tile and vinyl, soft bristles suffice.

Put some elbow grease into brushing so you can get any white water mold residue off your swimming pool surfaces.

Run the Pump

When you’re satisfied with how much white water mold residue you’ve removed, it’s time to run your pool pump.

Give the pump the rest of the day to run at least, as the filter will collect the mold residue you might have missed or that you dislodged into the water.


It might take several instances of cleaning the filter, brushing the pool, and running the pump, but eventually, you will get rid of the white water mold in your pool.

Vacuum the Pool

Although you think all the white water mold is gone, you can never be too careful.

Next, run your pool vacuum across the entire pool, taking care not to miss any surfaces as you go.

Be sure to test the water levels one more time for a balanced pH and you’re good to go!

How to Get White Water Mold Out of a Biguanide Pool

A biguanide swimming pool utilizes a sanitizing liquid that contains no chlorine. Instead, the liquid compound is made of polyhexamethylene biguanide or PHMB.

You can’t exactly shock a biguanide pool, so how do you remove white water mold?

Much of the steps above will be the same. You still want to clean the filter to start, then balance the pH.

Instead of shocking the pool though, you should use an oxidizer. For every 10,000 gallons of water in your pool, you’ll need between three and four gallons of oxidizer.

The oxidizer works the same way as chlorine shock, killing both bacteria and fungi in the water.

Then you’d brush your pool, run the pump, brush a second time, pump the water again, and finally, vacuum your pool.

How to Avoid White Water Mold Recontamination

Unfortunately, white water mold is prone to recontaminating surfaces that you might have thought the mold was long since removed from.

Even a little bit of mold can recontaminate your pool, so you have to be diligent in following the above removal methods immediately at that point.

How to Prevent White Water Mold

One instance of white water mold is more than enough for you. How do you prevent recontamination of your pool in the future?

Here are some tips to follow.

Keep Your Pool Clean

A dirty pool doesn’t make it likelier that your pool will develop white water mold, but it does make it harder to detect the mold.

Make sure you’re regularly cleaning pool surfaces and shocking about once a week. You should not use as much shock as when trying to kill white water mold, just as a reminder.

Test the Water Chemicals Regularly

Balanced pool chemistry will make shocking more effective and also ensure the cleanliness of your swimming pool. At least weekly, pull out your pool water chemical balancing kit and test the levels of chlorine, pH, and more.

Don’t Apply a Pool Cover Too Often

Putting on a pool cover during the active season but when no one is using the pool might save you on cleanup later, but you could be causing or exacerbating a white water mold problem.

The sunlight can kill mold, so the more sun the pool water gets, the better.

If you must use a cover, then at least put it on after dark.

Clean Your Filter

Your pool filter works continually to remove contaminants in the water, possibly including white water mold.

As often as your filter type requires, follow the instructions from earlier in this article to clean the filter.

Does White Water Mold Sink?

When looking for white water mold in your swimming pool, should you have your eyes trained at the bottom of the pool, somewhere near the middle, or at the top? The answer is at the top, as white water mold floats. It will look like someone dropped several tissues in your pool, except tissues would have sunk.

Can You Swim with White Water Mold?

If you had a summertime soiree scheduled with friends and family, do you have to cancel now that you’ve found white water mold in your pool? Or at least encourage everyone not to swim?

That’s at the discretion of your guests. You’ll recall that white water mold is regarded as harmless to human health. However, it also floats and has an unpleasant texture, not something that people would really enjoy swimming in.

Thus, the best thing to do for everyone’s safety is to address the mold first and let everyone swim later.


White water mold can put a damper on pool parties and other summertime plans. Even though the mold isn’t dangerous, it’s unappealing and will spread if allowed to.

Now that you know how to remove white water mold from your pool and keep it gone, you can enjoy more tranquil summer days.

Chris Walker

Chris Walker has struggled for several years with mold after buying his own property. After finding the solutions to several issues around his home, he decided to create this site in order to answer as many questions about mold and mildew as possible to help others dealing with the same problems.

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