How to Clean a Water Cooler


Water coolers are a convenient way to offer clean water in offices, gyms, homes, etc. Although the water we run through them is clean bottled water, germs and unwanted growths quickly occur in these moist environments. It’s important to clean your water cooler each time you change the bottle or every six weeks, whichever comes first. Keeping your cooler clean will ensure all those that benefit from it will be free from germs and dangerous bacteria as well.

Cleaning your water cooler can be completed fairly easily and quickly if done on a regular basis. The Brookhaven National Laboratory offers a thorough guide to clean your water cooler.

You Will Need:

The Cleaning Process:


  1. Begin by mixing a bleach solution of 1 tablespoon bleach per gallon of water. (Unused portions of this solution can be stored for up to 30 days.)
  2. Unplug the water cooler. It’s important to NEVER clean the unit while it is still plugged in.
  3. Remove the water bottle. It’s most convenient to complete this cleaning when switching bottles and the bottle empty.
  4. Drain any remaining water from the reservoir through the faucet into a bucket.
  5. Fill the interior reservoir with the bleach solution. Let it set for about 3 minutes.
  6. Use the scrub brush or sponge to scrub away any build-up from the walls of the interior. If there are additional removable parts in the interior, remove them, clean either in the bleach solution or with a mild dish detergent and replace.
  7. Drain the water by emptying it through the faucets into a bucket. This allows the faucets to be disinfected as well.
  8. Rinse by filling the interior reservoir with clean water and emptying it through the faucets into a bucket at least FOUR times or more until the water no longer has a bleach taste.
  9. Remove the drip tray and screen.
  10. Wash both of these items in the bleach solution or with a mild detergent.
  11. Rinse thoroughly with clean water and replace on the unit.
  12. Next you will prepare the new water bottle to be inserted into the cooler.
  13. Put rubber gloves on and wipe the top of the new water bottle with the bleach solution.
  14. Insert it in the cooler and let it fill the reservoir.
  15. Use paper towels and the bleach solution to wipe the exterior of the cooler along with the faucets.
  16. Plug the unit back in and allow about 30 minutes for it to bring the water back to the desired temperature.

Additional Tips and Advice

  • It’s helpful to designate a specific individual in the office or at home who is responsible for cleaning the water cooler on a regular basis.
  • Be sure to store unused water bottles in a clean area that is cool and well ventilated.
  • Be cautious not to touch cups or personal water bottles to the spigot when filling. This is a prime way to spread germs.
  • If you have a hot/cold tank, plug the hot tank so no bleach solution can enter. This area is sanitized because of the heat and does not need to be cleaned with the bleach solution. If bleach enters this area, it will take several days for it to be removed completely.
  • Be cautious not to get the air filter wet during the cleaning process.



  1. I have cleaned out the cooler and drained it many times, but still taste the bleach. What can I do to get rid of the taste and smell?

  2. Try running a mild baking soda through the tanks. Drain the tanks.

    First, mix the solution in a bottle (a 2 liter soda bottle will do). Add about 1 tsp. Position the bottle so it drains into the cooler’s reservoir. If the bottle empties before the reservoir is full, mix up another batch and repeat.

    Then repeat the above procedure. Then replacing the bottle, allow the water to fill in the reservoir. Wait 20 minutes then drain Sold reservoir till the water is no longer cold, and that should do it.

    Also, remember to disconnect the hot water. The baking soda would not be good for the hot water tank.

  3. I’ve seen suggestions that vinegar should be used instead of bleach. Both would leave an odor. Which one is easier to remove?

  4. My booklet tells me to use water with lemon juice and now I have noticed that there is some build up inside of the system. It tells me to not use bleach because I have a hot water and cold water?

  5. The issue of using vinegar is that even though it is slightly acidic, it will not disinfect as well as bleach and being an acid, will tend to attack the seals in any valves in the system.

    The key to disinfecting with bleach is to use the proper dilution ratio (1 tbsp/gal water) being careful to mix the solution thoroughly before running it through the water cooler. Those that have a residual taste or odor probably did not mix the solution properly or have an internal reservoir holding the cleaning solution and will take longer to dilute it enough until the taste is no longer present.

  6. I am trying to clean my Sunbeam Water Cooler; I have tried the vinegar and it did not work. The easiest way for me to describe the taste is to tell you it tastes like hose water from outside. It is gross! :( I have tried everything to clean this. I am not sure if I should try the bleach or not; I have soaked the parts and cleaned each one individually. Any suggestions would be greatly appreciated.

  7. You can buy a water cooler cleaning kit. It works good..

  8. I have white flakes that come out of my water cooler while dispensing water. I do have an older cooler and I wondered what it might be and how to clean the cooler and get rid of these. Any feedback would be appreciated!

  9. Oh dear. Never use bleach. Your water will taste awful and it is a pain to keep rinsing through; same goes for vinegar. Lemon may taste OK, but it’s not going to clean very well!

    Buy a CoolerClean home kit. It contains a cleaning chemical that is flavorless, odorless, and does not need to be rinsed out afterwards. Google it.

    Note: I am in no way connected to the makers of CoolerClean, I just hate seeing bad advice on the net.

  10. Rick, I have the same problem. I got my cooler from a physician’s office who was remodeling. It sat up for a while. I have done the vinegar/water solution as well and even wasted a five gallon bottle. I figured after five gallons ran through, it would all be gone. I guess I am going to try the bleach solution and see if it gets me anywhere. If it works, I will post and let you know.

  11. The white flakes are a form of algae called water mold. It grows in dark wet places. I’m in the swimming pool industry and water mold is quite common in pools; they use non-chlorine sanitizers. Chlorine is the only sure-fire way to kill water mold. If you are seeing the white flakes, that means that it has clogged the plumbing walls so that it is actually shooting out because it may be closing up the plumbing tubes. Just do the cleaning with bleach several times and that should take care of it.

  12. I have the same problem as Rick. What are these little white flakes?!

  13. I just bought a used water cooler off craigslist. Per my manual, it says to remove the removable parts first and wash them. Then pour warm soapy water into the reservoir. Drain through the faucets – repeat three times. Rinse with clean warm water through the faucets – repeat three times. Remove the drain plug from the back and drain all remaining water; rinse a couple times this way as well.

    Seeing that this was a used product, I proceeded to sanitize. The manual says mix two teaspoons of bleach to one gallon of water. Go through the same process as above with the bleach mixture.

    I misread tablespoons for teaspoons so I had to rinse a few extra times. My water does not taste like bleach and is perfect. If your unit has a drain plug on the back, make sure you completely drain the reservoir.

  14. What’s the best way to get rid of the white flakes that appear in the water??

  15. Dear All,
    What is the correct procedure for cleaning a water cooler if the water cooler is stainless steel?

  16. Michael says:

    I am surprised no one has mentioned simply pouring boiling water through the cold water spout. Is there any reason this would not effectively clean the water cooler? I found this page while looking for a way to clean my cooler, but based on other comments, I am a bit afraid to use bleach or vinegar.

  17. Robert S. says:

    Michael, one problem I can think of with just using boiling water through the cold water spout is that depending upon how the cooler was made, the seals and tubing may not be rated for high heat and you might damage the cooler. Another issue is that in order to properly sanitize through heat (which is how boiling water would work) it needs to be at that temperature for a period of time. Haven’t looked it up lately, but from my days (long ago) in a chem lab, sanitation through heat took a minimum of 10 minutes.

    The bleach solution is safe so long as it is mixed in the proper proportion; if you have the manual that came with your cooler, consult it. If not, as the author states, use no more than 1 tablespoon per gallon of water, and mix it thoroughly.

  18. Dear All,
    Bitter taste, not every time, but sometimes coming out from my water dispenser. I did all the cleaning by using the plain water and not by using any solution. But, it still is not producing the good results. The water is filtered using the RO process. Would appreciate your comments and suggestions.

  19. Folks, I have a water cooler and I’ve cleaned (and sanitized) it many times and never had the bleach or soapy water taste you guys talk about. Why? Well, I would venture to guess that anyone who doesn’t follow your original owners manual (Google a copy online if you don’t have yours) and ONLY followed the instructions here on this page have made a mistake in the amount of bleach you’re using. Above it said incorrectly to use 1 tablespoon per gallon of water. This is way wrong and way too much bleach. It’s 1 or maybe 2 teaspoons per gallon. If you’ve used a tablespoon all you can really do now is run fresh water through until the smell/taste of bleach is gone. I take mine outside and use the water hose to flush it out until cleaner than clean after letting the solution sit for 5 minuets.

  20. There appears to be a fishy oil substance in the water coming out of my cooler; any ideas what it might be? It’s a cold and hot water cooler.

  21. I used 1 tsp bleach with 1 gal of water and repeatedly poured it into the reservoir or tank of the water dispenser and then drained through the faucet. I consumed and wasted 1 gal of purefied water. Finally, rinsed it with tap water. At last no smell, and fresh water.

  22. I just moved into my brother’s home that was left unattended for several months, and when I used his water cooler, green algae came out. Is this salvageable or should I trash the water cooler? If it is salvageable, how do I fix it on a budget?

  23. Instead of having white flakes, my cooler has been putting little brown flakes in my water? Whats the best way to clean it?

  24. My water cooler sat up for a while. When we put in fresh water, we had the algae and rinsed and rinsed and now just a few white flakes, but they’re still there. I don’t want to use bleach because of the highly unlikely off-chance that I do it wrong; my kids drink water out of this cooler and I don’t want them getting sick…any other ideas?

  25. I’m wondering how to remove the stagnant water odor; the cooler has been sitting for several months??

  26. I appreciate this article because it addresses a concern I have in public arenas where water coolers are provided and yet not maintained. My only suggestion concerns chlorine, which could easily be replaced with less toxic and equally effective hydrogen peroxide. Other than this, I will recommend this process for raising awareness of this important maintenance and responsibility for public health.

  27. I have a water cooler. The water comes out of the cold faucet very slow. What can I do?

  28. Billy,
    There are several things that could cause the cold faucet flow to be slow. First, unplug the cooler, then look to see if there is any ice in the cold water well. If so, allow the ice to thaw and turn down the temperature for the cold water. If there isn’t any ice, you can try turning on the cold water tap and giving the bottle a squeeze to push the flow out more quickly, then turning the tap on and on again to see if the flow has increased permanently. Another option is to check the parts of your specific machine; if your cooler has hoses, check that the hoses are attached properly, or if there is a filter, check the filter.
    Source: Watchung Beverage Delivery – Equiptment Troubleshooting
    Source: The Water Delivery Company – Water Cooler Troubleshooting
    Source: eHow – Problems With Water Dispensers
    Source: YouTube – Cold water is dispensing slowly

  29. My cold light (green) isn’t on when I turn the switch.

  30. I recently purchased a used Clover water cooler. I’ve cleaned it twice with vinegar and once with a hydrogen peroxide solution. I took it apart and cleaned out the tap. The water has sort of a metallic taste. Any ideas on how to get rid of it? (I’m only using the cold water tap of the unit.)

  31. We have a Culligan water dispenser at our facility and have recently noticed some dark spots near the reservoir (where the bottle sit on the dispenser). I called our Culligan provider and they said it was algae and not mold. Has any one else seen this or identified it? What are the health hazards?
    Thanks for any information!

  32. Why is there no mention on how to remove the top to get to the dispensing area? This has to be done to be able to clean it.

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