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Bunn NHBX Leaking From the Bottom? Here’s How to Fix It 

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You can typically fix the leak in your Bunn NHBX 10 cup coffee maker by reinforcing or replacing the seal. 

A broken seal is the most common reason for a Bunn NHBX leakage. But there might be more to it.

I’ve been finding out all the possible reasons for this leakage so stay tuned to find out why it happens and what you can do to fix it.

I’ll be covering the following subjects in this article:

Let’s get started. 

Why is Your Bunn NHBX Coffee Maker Leaking From the Bottom?

There are four main reasons for your Bunn NHBX to be leaking from the bottom: the silicone seal could be damaged, there could be mineral deposit buildup, something might not be loaded properly or something else internal might be broken.

Take a look through the following possibilities and find out which of them has happened to your own Bunn NHBX coffee maker. 

#1 The silicone seal is damaged 

The most common reason for your Bunn NHBX leaking from the bottom is that the silicone seal inside is damaged.

The silicone seal is located between the water reservoir and the heating tank. This is what helps keep all the liquid inside of the machine. Occasionally, this can wear out or become torn as a result of incorrect loading or a lack of cleaning.

But it’s not necessarily your fault! A phenomenon called “planned obsolescence” means that the constant exposure to hot water can wear out the silicone over time. It’s a good idea to keep an eye on the seal occasionally to ensure it’s in good condition before you do get a leak.

You might find that either water from the reservoir will leak or actually brewed coffee depending on which part of the seal is broken. 

The only way to find out if this is actually the issue is to open up your coffee machine and take a look at the silicone seal all the way around. It should be pretty visually transparent that the seal is broken when you do this.

For help with taking the machine apart in the first place, refer to the section on the matter later in this article. 

#2 There is a mineral deposit buildup in the machine

Over time, minerals will build up inside of your Bunn NHBX coffee maker and cause your coffee to taste pretty nasty. But even worse, it can cause the coffee machine to spill out of the bottom! 

This is as a result of the water not flowing properly throughout the machine. It gets blocked off by the mineral buildup and can be forced out through the bottom of the coffee maker. 

If you have harder water in your area, a mineral deposit buildup is more likely to happen so you’ll need to keep a closer eye on it than those in softer water areas. 

To find out if you have a mineral buildup inside the machine, you’ll need to open it up and look around for a chalk-like sediment. You might find this in the water reservoir or anywhere else inside the machine that water flows through.

I’ll show you how to remove this sediment in the cleaning section later on.

#3 You’re not loading your coffee maker correctly 

Your leaking issue might be caused by something as simple as the way you load it up. For example, you might not be loading the filter or the coffee correctly, causing coffee to spill inside and through to the bottom.

You may also have overfilled the water reservoir. This could lead to too much water pouring into the machine and straight through the bottom. 

I’ll cover a few tips on how to use your Bunn NHBX later on. It’d be worth reading through these if you’re not sure you’ve got the technique for loading quite right. 

#4 Something internal is broken

The worst case scenario would be that something more sinister than the silicone seal has broken inside of your Bunn NHBX.

Again, the only way to find out how to do this is to have a look around inside. But even then, the breakage might not actually be visible. 

It might simply come down to the fact that you’ve exhausted all the other fixes in this article and the issue continues to occur. 

Don’t worry though, all hope is not lost. I’ll show you a few options for if you find yourself in this situation in the corresponding section later on in this article.

Overview of the Bunn NHBX Leakage Fixes 

Now that you’ve figured out what the issue that’s causing your Bunn NHBX to leak from the bottom is, it’s time to put a stop to it. Here are the fixes for all of the issues discussed above.

Replacing the silicone seal

As mentioned, the most common issue to cause the Bunn NHBX coffee maker to leak is a broken silicone seal. So, here are the steps you need to carry out to replace the seal.

As mentioned, the most common issue to cause the Bunn NHBX coffee maker to leak is a broken silicone seal. So, here are the steps you need to carry out to replace the seal.

Strangely, Bunn won’t actually let you buy a new seal for their coffee machine. But there is a trick you can carry out to make sure that the old seal is back to its original functionality.

Simply open the machine up and locate the area in which the original seal is broken. Then, apply a thin layer of silicone gel to the area in which the seal is damaged. Let this sit for a few minutes, then you should be good to go. 

Also make sure that the original seal is still fastened securely to the groove inside the machine the whole way around. 

You can get silicone sealant from any hardware store. It shouldn’t be tricky to get hold of. And remember, you only need a tiny amount (just a bead) to fix most Bunn NHBX seal issues. 

Not sure how to disassemble the machine in the first place? Skip to the section that covers this later on in this article. 

Remove the mineral deposit 

If a build up of chalk like sedative was your issue then all you need to do is remove it and you should be back up and running in no time. 

I recommend simply wiping out the sedative that’s built up (you might need to scrape it out with a metal object if there’s a lot) then carrying out a full descale of the coffee machine. I’ll show you how to do that later.

The best way to keep on top of this issue is to clean your Bunn NHBX coffee maker regularly. For more information on how to do that, scroll down to the ‘cleaning your Bunn NHBX coffee maker’ section.

You can also read this guide for more information about cleaning a coffee machine in general. 

Load your machine correctly 

Maybe the issue is that you’re not loading up your coffee machine quite right. If you’ve looked through the rest of the issues and it doesn’t seem to be any of them, this is the likely outcome. 

You can read more usage tips on the Bunn NHBX coffee maker later on in this article. I’ll show you how to load the machine correctly there. 

Replace broken parts or the whole device 

It might come to the point where you need to get some further assistance. If something on the interior of the device is broken, the only thing you can really do next is reach out to Bunn’s customer support team.

It’s not going to be possible to replace many of the interior parts with ease. I’d recommend avoiding doing this and leaving it to the professionals.

It’s probably more likely that Bunn will offer you a replacement device instead of repairing it. But they’ll charge you for that if the device is out of warranty or if the damage was caused by neglect instead of an actual issue with the hardware itself.

If you need to reach out to Bunn, there are a couple of contact methods available:

  • Send an email: For less urgent enquiries, you can send an email over to [email protected]
  • Make a call: You can speak to the Bunn Tech Services helpline by calling (800) 286-6070 in the US.

Personally, I’d recommend calling Bunn as they shouldn’t take too long to pick up and it’s going to be a lot quicker for you to get the help you’re looking for. It might take some time for them to get back to you via email. 

Disassembling Your Bunn NHBX Coffee Maker

You’ll probably need to take your Bunn NHBX apart to identify what the issue is that’s causing it to leak from the bottom. You’ll also need it to be open to fix certain parts. 

Disassembling the coffee maker is easy. Here are the steps to carry you out [1].

1. Unplug the coffee maker

Make sure there’s no power running through the coffee maker whatsoever to be on the safe side. Even if the device is powered off but plugged in, there could be some charge inside of it so the best thing to do is remove the plug altogether.

2. Remove the lid

To get into the device, just pull up the lid as you would do to normally load up your filter and coffee. 

3. Remove the parts

Now, simply pull on the coffee filter holder to remove it and you should be able to see all corners of the remove. This will allow you to inspect it for damage, limescale etc. 

If you want to remove the top reservoir separately you’ll need a Phillips screwdriver. You’ll see the screws where it attaches at the top of the device. 

There are further screws on the bottom of the device that you can use to remove the bottom casing. This is probably only really necessary for cleaning (as we’re about to find out) because there are no moving parts in that section. 

Further disassembling can be carried out but to do this, you’ll need to disconnect and reconnect the wiring. I’d only really recommend getting that involved if you have experience with soldering. 

Not all of the parts are removable, so be sure not to apply too much force as you may end up breaking something and exaggerating the problem! 

Cleaning and Descaling Your Bunn NHBX Coffee Maker

If your coffee maker has sprung a leak then you’re going to need to give it a deep clean. If you leave the coffee residue inside of the machine then it’ll become stale and ruin the taste of any coffees you make. 

Plus, poor cleaning can be the reason for the leak in the first place as we’ve already found out. 

Here are a few quick steps you can carry out to keep your Bunn NHBX clean. You should carry out these steps every three months or so if you use your coffee machine every day.  

1. Open the device and put a brew funnel under the tap. Put a plate or a bowl under the base plate to catch spillages and the vinegar you’re about to use.

2. Pour a splash of white vinegar into the device and wait for it to filter through. Let this sit for a couple of hours.

3. Pour a cup of water through the brewer to drain out the vinegar.

Earlier on, I mentioned how important it was to keep on top of any sediment inside your Bunn NHBX by removing mineral buildup. The process of doing this is called ‘descaling’ and the preceding steps should help with this as well.

However, you may also need to open the device up and scrape away any deposit if you haven’t cleaned the device in a while. 

Using Your Bunn NHBX Coffee Maker: Extra Usage Tips 

We’ve learned through today’s article that your Bunn NHBX might leak through the bottom due to incorrect usage. So to put that right, here’s a quick guide on using it properly and avoiding any of those mistakes.

  • Load the filter and coffee correctly: Make sure the filter is covering the whole filter tray and that you’re spreading the coffee evenly across it. Also make sure not to overfill the filter with coffee. 
  • Clean the device regularly: One thing you should be doing (that not a lot of people seem to) is cleaning your coffee machine every three months or so at most. Refer to the previous section to find out how to do that. 
  • Ensure that the coffee pot is loaded correctly: If you don’t click the coffee pot into the correct position, you’re going to end up with spillages.

Bunn NHBX Coffee Maker Leakage FAQ 

Here are a few other important pieces of information to consider when your Bunn NHBX begins to leak from the bottom.

How long should my Bunn NHBX coffee maker last?

You shouldn’t have to replace your Bunn NHBX coffee maker any earlier than the five year mark. But in fact, it could last a lot longer than this. Perhaps 10 years or more.

This also depends on how often you use it and how well you look after it in terms of cleaning it often and loading it correctly.

How long is the Bunn NHBX coffee maker warranty?

One cool thing about the Bunn NHBX is that it comes with three years of warranty as opposed to the standard one [2]. Triple the standard cover is great for peace of mind! 

If you have any issues with this period that you think are a result of a manufacturer defect then be sure to reach out to Bunn as you might be able to claim a repair or replacement free of charge. You can do this with the contact details provided earlier on in this article. 

Last Thoughts

You can usually fix the issue of a Bunn NHBX coffee machine leaking from the bottom by working on the silicone seal inside. But there could be other reasons such as a build up of mineral deposit or the device not being loaded properly in the first place. 

With the tips in this guide, you should never have to worry about a leaking Bunn NHBX again. Because if and when it does happen, you’ll know exactly how to fix it!

If you want to know more about how to use different types of coffee makers in general then check out this article.

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Tim Lee is, as you might have guessed the founder of He is a former barista and a professional web publisher. He has now combined his knowledge and expertise in both subjects to create
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2 thoughts on “Bunn NHBX Leaking From the Bottom? Here’s How to Fix It ”

  1. My bunn is leaking out the bottom. I cleaned the silicone gasket at the top but that had nothing to do with the leak. It leaks while the water is going in from the resivoir. So where’s the problem?

  2. Hey Mark!

    If your Bunn coffee maker is leaking from the bottom while you’re pouring water into the reservoir, the issue often stems from the internal components. Here are some common causes and potential solutions:

    If your Bunn coffee maker is leaking from the bottom, here are potential causes and solutions:


    1. Worn-out Internal Seal/Gasket: Seals can degrade over time.
    2. Damaged Tubing: Internal tubes may be loose or cracked.
    3. Faulty Valve: The valve controlling water flow might be malfunctioning.
    4. Mineral Buildup: Hard water can cause internal deposits.
    5. Reservoir Cracks: The water reservoir might be cracked.


    1. Check and replace damaged tubes or seals.
    2. Examine the valve for proper function.
    3. Run a descaling solution through the machine.

    If this doesn’t help, consult Bunn’s customer service.


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