How to Clean Mold from Keurig Water Reservoir

Does your coffee have an unusual musty or earthy taste? Sorry to say but your Keurig is most probably mold-infested. While the thought of it is scary, you don’t need to panic or trash your cherished coffee maker. All you need to do is learn the tricks of how to clean mold from Keurig water reservoir and it will be as good as new. But how can you do that?

Fill your Keurig halfway with a mixture of white vinegar and hot water then stir the mixture before you let it settle for some 30 minutes. This solution cleans the reservoir by itself but you can also run the solution through the other interior parts of the Keurig using the brewing function. Empty the solution; rinse the Keurig before using it again.

Keurig coffee maker infested with mold.

What is Mold?

The Centers for Disease Control and Prevention (CDC), says a mold is a form of fungi that thrives in moist, damp, and decaying organic matter and spreads by means of pores. It can grow on any damp area in your living space including on appliances, surfaces, and food.

How do Keurigs Develop Mold?

Mold spores occur naturally in the air and can grow at any time if surrounded by the proper conditions of moisture and an organic food source. Generally, all types of coffee makers including Keurigs for dorm room can be infested by mold.

All drink dispensing machines are perfect breeding grounds for mold due to the constant presence of moisture in their internal water lines. 

Signs of a Moldy Keurig

Besides having an unusual taste in your coffee, a foul odor from the machine and visible growth in form of black or green colored residue in the water tank are the common signs of mold invasion in your Keurig.

Is Mold Harmful?

Mold, whether ingested or inhaled, is potentially dangerous especially if you have asthma or allergies. It releases toxins that pose health risks especially allergies that present with cold-like symptoms such as sneezing, scratchy throat, itchy eyes, and headaches.

Now that we understand all about mold, let us focus on how to clean it from a Keurig water reservoir

How Do You Clean Mold From a Keurig Water Reservoir?

If your reservoir has mold, it would be foolhardy to clean it alone because the mold has most likely spread to other areas. We’ll therefore look at how to clean mold from Keurig water reservoir and the entire brewing system as well.

All the methods below involve passing the cleaning solutions through the brewing system so that the mixtures can flush out the mold as they flow through.

Cleaning preparations:

  • Put on a facemask if you are asthmatic or allergic to mold
  • Switch off the Keurig
  • Remove the water tank and empty it
  • Take out the filter holder and the mesh screen
  • Make sure there is no pod in the Keurig
  • Check for dishwasher-safe parts and clean them in the dishwasher

Cleaning Using Keurig Cleaning Solution

The Keurig cleaning solution is what Keurig recommends for descaling of all its coffee makers using the following procedure

  1. Mix water and Keurig cleaning solution in a 1:1 ratio and fill the reservoir with the mixture.
  2. Brew a cup of hot water and repeat the process at 5-10 seconds intervals until all the solution is drained from the reservoir.
  3. After getting the “Add Water” notification, let the machine sit for 30 minutes while still on to allow the solution to work on any stubborn mold.
  4. Meanwhile, wash and rinse the drip tray, filter holder, and mesh screen using the prepared solution.
  5. Rinse the water tank thoroughly under running water and fill it with fresh water.
  6. Put all the components back in the coffee maker and brew 12 cups of hot water to flush out all the cleaning solution from the system.

In case you don’t have the Keurig cleaning solution, you can use any other commercial descaler on the condition that you follow the manufacturer’s instructions to the letter.

Cleaning Keurig Using White Vinegar

Vinegar is just as effective in cleaning a coffee machine as any commercial cleaning solution. For a squeaky-clean Keurig, follow the procedure below.

  1. Fill the water tank with a 50/50 mix of vinegar and water.
  2. Stir the mixture and let it sit for 20-30 minutes.
  3. Scrub the tank thoroughly with a round-tipped brush without forgetting the water intake hole and pour the mixture out.
  • Fill the tank again with a similar cleaning solution. Turn on the brew function and brew hot water until the entire solution is almost drained from the reservoir.
  • Let the remaining solution sit in the brewer for about an hour without switching it off.
  • Meanwhile, put a mixture of water and vinegar in a bowl and soak the mesh screen, filter holder, and drip tray.
  • After one hour, empty the tank and rinse it multiple times to clear out any traces of vinegar. Wash the drip tray, mesh screen, and filter holder also, and put them back in the Keurig.
  • Fill the tank with clean water and run the brewer several times to flush out the cleaning solution. Vinegar-flavored coffee is not something you want to try so brew as many cups of hot water as necessary until the strong vinegar smell is gone.

The Baking Soda Cleaning Method

Baking soda is a great cleaning agent due to its abrasiveness. The following simple steps will guarantee you the best results when using baking soda to clean your Keurig.

  1. Make a paste using baking soda and water.
  2. Apply it inside the reservoir walls.
  3. Let it sit for a while then scrub the tank thoroughly and rinse it under running water.
  4. Wash the drip tray, mesh screen, and filter holder using the remaining paste, and put them in the open to dry.
  5. Make a fresh mixture using ¼ part baking soda and ¾ part water and fill the tank with it.
  6. Brew the mixture just like you normally brew your coffee until the tank is empty.
  7. Repeat steps 3 and 4 a few times to clear out the entire mold.
  8. Rinse the tank and fill it with clean water.
  9. Run the brewer multiple times until you clear all the baking soda from your Keurig.

How do you Prevent Mold Build up in Your Keurig?

Prevention is always better than cure. Therefore, observe the following simple measures to ensure mold does not invade your Keurig:

  • Change the water in your reservoir regularly.
  • Leave the lid of the water tank open when not in use to allow it to dry.
  • Wipe the inside of your Keurig dry after use.
  • Empty, clean, and dry the placement tray regularly.

Frequently Asked Questions (FAQs)

Q: Do Keurigs get mold inside?

A: Like most coffee makers, Keurigs have the ability to grow mold inside because water sits in the plastic reservoir for a long time, making it the best breeding place for mold.

Q: Why is mold growing in my Keurig?

A: Keurig and other coffee makers are prone to growing mold because of the moisture that is present in the internal water lines.

Q: Can algae in Keurig reservoir make you sick?

A: Studies indicate that algae in Keurig water reservoirs, as well as other coffee makers, can make one sick.

Q: What is the green stuff in my Keurig water reservoir?

A: The green stuff inside the Keurig reservoir is algae that has build-up due to a lack of regular cleaning.

Q: How long can you leave water in Keurig reservoir?

A: Generally, you can leave water in Keurig reservoir for 2-3 days but you need to reheat the water before you use it again.

Q: What does descaling on my Keurig mean?

A: When you press the descaling button on your Keurig, you start the process of removing calcium deposits or scales that have built up inside your coffee maker.


Keurigs are prone to mold invasion and learning how to prevent the invasion and how to clean mold from Keurig water reservoir is important since exposure can lead to serious health problems. Luckily, getting rid of mold is a simple process; as simple as running a cleaning substance through the brewing system just like you do your coffee.