How Long Can You Leave Water In A Keurig Reservoir?

Does The Water We Use Matter?

Before we discuss further, it is essential to establish what water hardness is and how it differs from state to state. In simple terms, water hardness refers to the amount of dissolved calcium and magnesium is present in the water. As some organizations have stated, we need minerals to thrive. However, it is not ideal for coffee makers. 

As the USGS states, once you heat hard water, a solid form of calcium carbonate can form. For your coffee maker, this means frequent mineral buildups. If you must use water from the tap, make sure to identify if it classifies as soft water. Otherwise, Keurig recommends using bottled water or filtered water in their machines.

What It Means For The Reservoir

What It Means For The Reservoir

In general, the best practice is to use the entire reservoir and keep it dry when it is not in use. This way, you will minimize limescale buildup and prevent mold growth. However, convenience sometimes is the better option than a little more cleaning.

If you can not avoid using hard water, you should not leave it in the reservoir for more than 12 hours. Any longer than 12 hours will require you to clean the reservoir more frequently. You might notice a white buildup that will need vinegar or lemon juice to clear.

Otherwise, bottled and filtered water is the better option. However, there are still some factors to consider. You can leave it in the reservoir for 3-4 days. But, to avoid bacteria growth, you should refill it with fresh water after that period. Reheating the water before use is also a good practice.


How do I clean my Keurig with vinegar?

Fill the water reservoir halfway with vinegar. Add water: Fill the reservoir the rest of the way with water. Run the machine: Start the brew cycle without inserting a K-cup. Repeat until reservoir is empty, discarding the mug contents after each brewing cycle.

How does a Keurig work?

All Keurig brewer models feature a water reservoir that stores large quantities of water—allowing the owner to simply press a button to brew their coffee. Upon doing this, small pins pierce the K-Cup to deliver the heated water and to distribute the freshly brewed coffee.

Which Keurig model makes the hottest coffee?

Most Keurig coffee makers do NOT have a temperature adjustment.

To get the hottest cup of coffee, you want to get a Keurig that lets you adjust the temperature. So, the one you want is the Keurig K-Elite Single-Serve K-Cup Pod Coffee Maker (click to see the current price on Amazon).

It brews your cup in under 1 minute and allows you to select a range of temperatures for the coffee serving temperature, between 187-192°.

At almost 5 stars and well over 1,000 reviews, this one just makes a lot of sense.

I will say another model, the Keurig K575 also has a lot of great features, including 5 temperature settings AND it’s able to dispense hot water on demand (for tea, soup cups, etc) and those are great features.

Unfortunately, at $550 it isn’t really an affordable option for the average buyer. Fortunately, however, Amazon says the Keurig K-Elite is the “newer version” of the K575. It’s much more affordable and gets excellent reviews.

Are you using a Keurig but not getting your coffee as hot as you’d like?

That’s frustrating as no one (aside from my wife) likes lukewarm coffee! Luckily, I have some solutions and recommendations in this recent article on my site.

Just click that link to read the article on my site to find out what coffee maker makes the hottest coffee.

Keurig- set timer w/ hot temperature level. No more waiting! 30 seconds coffee on the gO!!

— irenemelody H. (@irenemelody) January 14, 2014

14. Keurig dispensing grounds in the cup

Here is troubleshooting for your Keurig K compact that keeps dispensing coffee grounds in your cup:

  • Using the wrong ground size to refill K-cup.
  • Pod failure or incorrect pod size.
  • Clogged needles caused by hard water scale.
  • Wrong pods’ lid placement.


If you are using reusable filters, use coarse coffee grounds. Also avoid overfilling the K-cup as it may make the coffee grounds settle in your cup.

If you find that needle clogging is the reason for the machine dispensing the grounds in your cup, use a paper clip to unclog the exit needle. Run a couple of water-only brew cycles to check for grounds coming out. The cycles will also help clean any residual grounds.

3. Keurig isn’t resetting

 It is not assembled properly It has damaged or diResetting your Keurig should be easy as ABC, but you may encounter some challenges. Here are some possible reasons why your Keurig won’t reset:

  • It is not assembled properly
  • It has damaged or dirty parts
  • Its internal computer systems have a malfunction

Here is how to reset your Keurig in case you are experiencing some trouble with it:

  • First off, turn off the machine then unplug it for a few minutes.
  • Before you plug the machine back in, remove the water reservoir then wait for some time.
  • Plug the machine then power it up.
  • Place back the water reservoir on the machine. Ensure you realign the magnet for correct placement.
  • Open and close the K-cup holder.

In some cases, the basic reset won’t work and you may be required to do an advanced resetting. The advanced resetting will reset the internal computer system of your brewer and resolve any existing technical glitches. Here’s how to go about it:

  • Power on your Keurig then press the small and medium cup button at the same time.
  • Release both buttons at the same time then press the ‘menu’ button thrice. You should see a 06:09 on the clock if you perform the steps correctly.
  • Press the ‘menu’ button once again. The digital display will change to ‘brew 0:00’.
  • Press the medium cup button and the ‘menu’ button simultaneously. Release the ‘Menu’ button while you are still holding the ‘Medium cup’ button.
  • Do not stop holding the small cup and medium cup buttons. Release them at the same time then unplug your machine for several minutes, then plug it back on.

If you can’t reset your Keurig after trying all these fixes, you can contact the Customer care support.

Does A Keurig Get Hot Enough To Kill Bacteria?

There are a few factors affecting bacteria growth

There are a few factors affecting bacteria growth and how they die off. Temperature and time are what affect the bacteria present in your Keurig. In general, the boiling point of water is 208 degrees Fahrenheit. 

Bacteria will die off with water that reaches 212 degrees Fahrenheit. But, the temperature is not the only requirement. The water should boil for at least 1 to 3 minutes. This timeframe is a long enough period to kill 99% of bacteria. 

If we take a look at a Keurig, water typically reaches a temperature of 200 degrees Fahrenheit. This range also applies to most coffee makers. So, it falls short of boiling point. Additionally, it will not stay hot for an extended period. With all things considered, Keurigs will not get hot enough to kill bacteria. 

How to Take Care of the Keurig Water Reservoir

You could easily just use a coffee maker with a removable water reservoir so that you can clean and refill it easier. However, one cannot simply ignore the quality of a Keurig coffee maker. You already know how long you can leave water in Keurig reservoir, which is no longer than 12 hours. So, if you have one, and it is contaminated due to keeping water inside it for a long time, there are several ways to take care of the water tank. 


Descaling means removing all the minerals and calcium that builds up inside the water reservoir. You may have noticed that when you boil hard water, a thick layer of minerals remains in the container after having used that container for some time. This is also the case with coffee maker water reservoirs. The Keurig water reservoir needs to be descaled every 4-6 months. One thing you can do to make sure not too much calcium and minerals get piled up inside your reservoir is to use bottled water or filtered water that doesn’t contain too many minerals. AN easy way to do descaling is using vinegar, baking soda, or Keurig Descaling Solution to clean the tank. Just fill the tank up with the solution, clean, and repeat for a few times. 


This process should be repeated every week. A water reservoir in a coffee maker is just like any other dish in the kitchen and needs to be washed. The best way to go about doing this is dismantling the coffee machine to get the water reservoir out. Next, you can easily use hot water and vinegar to clean all the molds and bacteria that exist. This ensures that no bacteria will remain in your water tank. You can also use baking soda to clean the tank. Remember that this water reservoir is not dishwasher-friendly, so avoid putting it in there. After you pour vinegar or baking powder mixed with water inside the tank, leave it there for a few minutes. Next, grab a brush and start scrubbing to make sure nothing is stuck to the walls of the tank. After that, simply wash it, and do it all again next week.

Running a Cleansing Brew

Remember we talked about how heating the tank up can get rid of most bacteria. This can help you now. You can easily start the machine with no K-cup in it, and wait for it to boil the water and clean the reservoir naturally. This doesn’t give you a cup of coffee, but a cup of hot water. You can repeat this several times to get all the water out. This is like shooting two birds with one stone: you clean the reservoir and you do it without having to dismantle the tank and take it out to clean.

How do I hard reset my Keurig

To reset a Keurig brewer:

  • Turn the brewer off and keep it unplugged for some minutes.
  • Plug it back and start a brew cycle again.
  • If unplugging doesn’t work, remove the water reservoir before plugging the machine and keep the brewer unplugged for some minutes without water and the reservoir attached.
  • Plug and power the machine and replace the reservoir.
  • Opening and closing the K-cup holder will reset the brewer if the brew cycle was interrupted.

When basic reset steps fail, you may need to use advanced reset techniques. To reset Keurig brewers with digital displays:

  • Simultaneously press the small and medium mug buttons, and release at the same time.
  • Press MENU three times immediately after releasing these buttons. The clock will read 6.09 if these steps are done correctly.
  • Press MENU once again and the display should change to say “brew 0.00”.
  • Press “medium mug” and then press MENU and release while still pressing “medium mug”.
  • Continue pressing “medium mug” and press “small mug” then release both buttons simultaneously.
  • Unplug the machine for several minutes before plugging in again.
  • The process resets the internal computer and should clear any glitches.

Keurig 155 Brewer will not brew

If your Keurig 155 brewer will not brew, try these troubleshooting tips:

  • After placing the K-Cup pack in the pack holder, make sure the handle is pushed down securely and the LCD control center reads “READY TO BREW” with the BREW button flashing, then press the BREW button.
  • The exit needle may be clogged and will need to be cleaned. Use a paper clip or similar tool to clean the exit needle which is located on the inside bottom of the k-cup pack holder.
  • If the water reservoir is empty and needs to be refilled, the LCD screen will direct you to lift the water reservoir, fill the water reservoir, replace the water reservoir with a slideshow of images. Follow these instructions.
  • In pour-over mode, if the water flow has been interrupted, the LCD screen will state “Water Flow Interrupted”. To reset, lift, and remove the water reservoir. When the reservoir has been removed the screen states “If necessary please fill the water reservoir to Max Fill Line. Then replace”. Follow these instructions.

Did I answer all of your questions about putting hot water in your Keurig?

In this article, I talked about whether it’s a good idea to put hot water in your Keurig.

I discussed whether you could put hot water in your Keurig reservoir and whether it would hurt your machine. Not only could adding hot water to your Keurig be bad for your machine, but it could be bad for you, too.

I also talked about which Keurig model makes the hottest coffee and how hot they get the water.

But most importantly, I answered the question of whether you can put hot water in your Keurig.

What type of Keurig do you have? Will you start putting hot water in it?

Photos which require attribution:

Keurig Pouring Coffee by Tony Webster is licensed under CC2.0


Using a Keurig brewer is a great way to make single cups of delicious coffee or tea in just minutes. But, to keep your Keurig performing at its best and prevent any issues down the road, it’s essential to maintain it.

Now That You Have Busted the Ghost in Your Keurig

The tips and tricks to get around our Keurig troubles generally apply to most of the Keurig Coffee Machines. Whether you have a Keurig Mini, Keurig 2.0, Mr. Coffee Keurig or Keurig Rivo these are some of the handiest Keurig troubleshooting tips and generally apply to any Keurig Coffee Maker.

You have most probably busted the spooky Keurig trouble by now, but if you could not, then the problem with your device is more complicated. It is a great idea to call Customer Care and let the manufacturer have a look. They are just a call away.

Dial the toll-free number 1-866-901-BREW (2739) to reach Keurig Support.

How to Care for Your Keurig Coffee Maker

Always Use a Clean Cup to Fill Your Machine

Using a dirty cup can introduce bacteria and mold, which can affect the taste of your coffee and possibly impact your health.

Leave the Lid Open When Not in Use so the Reservoir Can Dry

If you use a Keurig Mini or other single-serving coffee machine, consider leaving the reservoir lid open when not in use. This will allow the water tank to dry. A wet tank that is not used for a few days will is an ideal environment for mold, which would end up in your coffee the next time you use your machine.

Remove and Clean the Platform Tray for Mugs From Time to Time

Excess water and coffee drain into this tray and can cause gunk to develop. If you use your Keurig often, this tray will likely contain standing liquid and mold. Use a damp cloth and some dish soap to wipe any water away.

Use Bottled Instead of Tap Water

Bottled water has fewer minerals than tap water and will cause little or no buildup in your machine. Bottled water can be expensive, however. An affordable alternative is to use a water filter, which will remove most of the mineral content.

Wipe the Coffee Maker Dry After Use

Use a paper towel to wipe the inside of your Keurig dry after use. Mold is less likely to develop in a dry environment.


The best Keurig coffee maker for you will depend on your needs and budget. We like the Keurig Elite for its versatility and programmable features. But you can check out our full guide to the best Keurig coffee makers here.

Yes, you can make iced coffee with Keurig machines. Extract a shot of coffee over a mug of ice, then add milk and sweetener to taste. The Keurig K-Elite has a special “Iced” function that brews a strong shot suitable for iced coffee.

The biggest difference with the Keurig 2.0 compared to classic models is that the 2.0 will only brew with Keurig-brand K-Cups. The machines do feature some additional functions, such as brewing larger cup sizes, including carafes of coffee.


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