White Water Mold

White water mold is a natural fungus that can form in swimming pools, hot tubs, and even your garden hose. It likes to grow in damp areas, so plumbing, pool toys, filters that are reinstalled wet, and even the garden hose make the perfect environment for it to grow. Seeing these white flakes in your water can indicate a bigger mold problem within your plumbing, as well as problems within your water chemistry, so it’s best to act quickly.


What does white mold look like in hot tubs and pools?

White water mold looks like white flakes floating around the top of your water or along the water line; almost like a shredded, used tissue (it can even be slimy and snotty looking).



Is white mold dangerous?

White water mold itself is more gross than toxic, though it does mean your water is likely inadequately sanitized - not good for soaking. However if this type of mold is left untreated it will wreak havoc on your hot tub water, if it hasn’t already, and can quickly lead to the formation of pink mold - which is dangerous.


What causes white water mold? Can it be prevented?

As we learned earlier, this kind of mold like to live in damp places. With a pool or hot tub, white water mold outbreaks can come from a few places:


  • Bathers shed skin cells, body oils, lotions, and a variety of personal care products into the water. If adequate bromine and chlorine levels are not consistently maintained, these pollutants are allowed to mix, grow and an outbreak of mold can occur. Showering (without soap or products) immediately before using the spa can help ease the workload on the filtration system, though sanitizer levels should always be tested and corrected weekly at minimum
  • Adding damp filters or toys to your pool or hot tub water can put it at risk for a mold outbreak. Clean all toys/filters regularly and allow them to dry completely before they go back in the water (ideally under the sun, as UV rays act as a natural oxidizer)
  • Filling with water from a contaminated garden hose can transfer the mold to your pool/spa water. Examine your hose and nozzle for signs of mold if you think this could be the culprit
  • Not regularly cleaning your surface walls, filters, and others components allows mold to breed uninterrupted. Plan for a thorough clean of your spa quarterly (read more on maintenance schedules)


Prevention is key! If you follow these tips and keep up with regular maintenance and care, mold shouldn’t be able to grow within your pool or hot tub.


How do I get white mold out of my water?

It’s important to take time and thoroughly clean your pool or hot tub of any white mold, as any smart particles left behind can grow back into a massive problem. The process is a bit different for pools as opposed to hot tubs.


Removing White Mold from a Hot Tub

Since draining a hot tub is considerably easier than draining a pool, it’s a good idea to flush the moldy water where weather and situations permit in order to make sure the mold is thoroughly cleaned out. Remember to be meticulous in your cleaning to ensure all mold particles are removed. If any spots of mold are missed, it can regrow out of control again quite rapidly and you'll be back to square one, so make sure to triple check your work!


Check that all jets, diverter valves, waterfalls, pipes, and any other water features are fully open and flowing water


Before you start cleaning, take a look at your filters. If they’re newer and in good condition, you can probably just kill the mold on them by doing a chemical filter soak with a filter cleaning agent like the Spa Essentials Filter Cleanser. If they’re over the 1 year mark, looking discoloured or frayed, consider just replacing them. The filter is your first line of defence again bacteria and molds, so especially right now you'll need a filter working at optimal strength


Super chlorinate the water to levels of at least 20ppm for a minimum of 72 hours to kill the mold and bacterias. Check the water every 24 hours to ensure adequate levels of chlorine; during these checks also drain a bit of the super chlorinated water into the spa drain to ensure no mold is alive down there


After the 72 hours have passed, use a pipe cleaner specifically formulated for spas like Pro-Clean Whirlpool Flush to remove the dead bacteria and slime leftover in the pipes. Generally the pipe cleaner will need to circulate through your hot tub with the pumps on high speed for at least an hour before draining (always follow the directions on the bottle of the product you're using)


Fully drain all the water out of your spa to remove all the residue from your spa. Give the shell a good scrub while it's empty to remove any stuck on grime that may have formed using a hot tub cleaner.


Fill the hot tub with fresh water, then circulate shock through the water as you normally would to break down any stubborn biofilm that may be left circulating throughout the plumbing; drain for hopefully the last time.


Fill your spa with fresh water, then power it on while observing the jets to make sure no white flakes are coming out. If you do still see these mold particles, drain the spa and fill it again to flush the plumbing further until you have a spa with clear water.


Put your new/clean and dry filters back into the hot tub.

Chemically balance the water as you normally would after a fresh fill.

Set up a maintenance plan to stay on top of water maintenance! Mold doesn’t show up overnight, so if you’re able to keep a clean spa with balanced water, you should be able to maintain clear and clean water.


  • Removing White Mold from a Pool

    You’ll need to shock the pool to kill the mold which can only be done when the sun has gone down, so plan accordingly before starting.


    Clean your filtration system as you normally would. There’s likely mold in here and we’ll want to remove the surface layer of gunk first (we’ll do a more thorough clean later)


    Test your pool water and make sure chemical levels are balanced, specifically the pH (don't worry about the sanitizer levels as we're about to super chlorinate, but do make a note of where it's at - inadequate levels could by why the mold formed in the first place)


    Shock the pool to super chlorinate the water; you’ll need to use 3-4 times the normal amount of shock in order to get adequate levels of chlorine to kill off the mold


    Clean the surface of your pool using a stiff brush, as well as scrub in all around jets, skimmers, ladders and parts to make sure no mold is lurking around


    Leave water to circulate throughout the pool for at least 24 hours to allow for the super chlorination to work and the scrubbed off mold to circulate into the filter


    Brush the pool surfaces again; you may have missed some mold particles or more may have settled back into nooks and crannies while water was circulating. We don’t want to leave any mold particles left behind in the pool.


    Vacuum the pool manually to thoroughly clean the water; have your garden hose handy to top up if the water line gets too low.


    Clean your filter again, this time using a chemical cleaner such as Filter Perfect to deeply clean your filtration media of bacteria


    Test and balance the water. Then test and balance the water again, and again. Ensure pH, alkalinity and chlorine are always strictly within range, and develop a routine maintenance schedule to ensure levels remain consistent so the problem doesn’t repeat


    Watch for white mold in the next coming days - it’s possible you missed a spot, even with the most thorough cleaning. Run the pump and clean the pool often, just to ensure no particles are left behind idle to grow


    Mold is one of the more tedious problems to solve, so preventing it is always the goal. Remember to keep on top of your chemical levels and follow your maintenance routine for beautifully clear, clean water.