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How to Deal with White Water Mold

by BrianReeves
mold on swimming pools

White water mold (WWM) is an organically occurring fungus, which has a white mucous or tissue paper-like substance.It forms a heavy, protective coating, providing the organism with an uncommonly high level of protection that is very resilient against both halogen-based (chlorine, bromine) and non-halogen sanitizers and germicides, and it can White water re-contaminate long after it was destroyed.


WWM can be found on pool ladders, toys, floats, steps, automatic pool cleaner parts, fountains, directional fittings, skimmer baskets, weirs, and garden hoses, etc. Even tiny quantities of it can cause the problem to reoccur. It is usually caused by improper water and pool maintenance, environment and poor circulation. Basically, it is an overgrowth of naturally occurring Biofilms lying on pool surfaces and hiding in spots that are less accessible.


It goes without saying that prevention of WWM is preferred over treatment, so here’s what you should do to keep it at bay. First of all, physically brush and clean all (and I mean all) pool surfaces on weekly basis, including ladder steps and rails, and expose them to as much sunlight and UV as possible, as they are natural oxidizers.

Remove the lid from the pool skimmer to allow sunlight into its basket for a few hours each day, but do this with extreme caution so as to avoid falling into an open skimmer. Regularly pour oxidizing chemicals into the skimmer in order to purge and clean the filtration lines of any biofilm.

When adding water with a garden hose, allow it to run for a couple of minutes prior to placing the hose into your swimming pool. Regularly clean pool toys, floats, as well as pool solar blanket if you have one. Run the pool filter at least 12 hours a day to prevent the so-called dead spots in the pool, and chemically clean the filter every 4-6 weeks, we learn from renowned Sydney-based pool builders.

Keep the pool water balanced at all times, rechecking after heavy rain or substantial top-offs of new water. Water balance refers to sanitizer and pH levels, calcium hardness and total alkalinity. Adding regular maintenance dosages algaecide every 2-3 weeks is also a prescribed
measure. Finally, don’t forget to clean and rinse all the hoses, vacuums and brushes that you use to maintain your pool.


In case pool mold occurs despite all your maintenance efforts, its treatment must be quick and thorough. Immediately clean all affected surfaces as described above, and then physically clean and remove all visible WWM. Now add the prescribed dosage of algaecide to your pool, and shock the pool with a triple or even quadruple dose.  Run the filter continuously until water is clear and peroxide and halogen levels reach high levels, and then chemically clean it. Take a water sample 4-5 days afterwards for a retest and evaluation, making sure that  there’s a good water balance of total alkalinity pH and calcium hardness.

Author Bio: Lillian Connors is a blogger and home improvement enthusiast ever so keen on doing various DIY projects around her house and passionately writing about them. She is also an online marketing consultant, closely collaborating with a number of companies from all over the globe. You can check her out on G+, Facebook and Twitter.

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john coggins September 17, 2015 - 9:57 am

i think i have got white water mould in my toilet bowl, it is a bit like soggy toilet paper and sticks to the toilet brush. it was not present yesterday.
i have heard it can be related to diabetes, which i have. i have also been suffering from an upset tummy for the past 2 weeks and wonder if they are connected.
what is the treatment to ged rid of this stuff please?

CHRISTINE September 25, 2016 - 2:26 pm

If I were you I would go to the doctor because most likely if it’s in your toilet water in your drinking water and that could be why your tummy is upset

Breyona January 11, 2020 - 5:43 pm

I have a white fungus growing in my fish rank because i havent cleaned it i n a while ny fish are dead and then slimey algae started to grow and now that some is above water a tiny white fungus has started growing on it i have no health issues currently i am going to clean it tomorrow and i hope it is not super harmful to me or my dogs.

frank June 11, 2020 - 8:03 am

I have white on the bottom of my pool we never open the pool last year when I went to vacuum the bottom liner it would streak white I have shocked the pool with 5 to 8 gallons of chlorine so far ,, when I try to vacuum it seems the white stuff is like stuck to the bottom like a layer of chalk .. you have any help ?

LynW July 29, 2020 - 7:06 pm

I recently bought a jug of Chippewa Falls “Spring water” and usually it’s my favorite brand. Not anymore. After using half of it (in coffee) the remainder had a very terrible rusty flavor, then took on a rusted color the longer it was open, and when I looked inside there was rusty sediment and a disgusting, gelatinous, white foreign object floating in it, about the size of a large white bean. I think maybe it is this white mold? I googled this company and an article said that the Chippewa Falls area has contaminated water even as terrible as farm runoff and septic systems. I also read that much of the drinking water sold in jugs as spring water is actually just tap water. This is so upsetting not knowing what I actually drank. Heading to get a reverse osmosis tomorrow. And back to my well water.

larhonda roberts September 7, 2020 - 10:01 pm

I have WWM and have not had a clear pool all summer. We are closing the pool for the season and i have washed everything with bleach. Next spring when I open the pool is it ok to wash the pool walls and floor with a bleach mixture? If yes, what ratio of bleach and water should I use. If I can’t do this, what would you recommend to clean with?

Jayne Biswell June 16, 2021 - 6:48 pm

My pool has a white hard Layer on most of the bottom and sides. My pump was going out was replaced. Tried scrubbing with wire brush, got very little off. Today a pool Maintance person told me he wasn’t sure but could be white fungus. It’s not any where else. Not slimy just hard. I’m thinking it’s calcium buildup
If you have any advice I sure would appreciate it. We do have very hard water. Pool is 8 years old. Made of concrete.


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