Why does My Bunn Coffee Maker Overflow?

The Bunn Coffee maker is famous for delivering a rich coffee experience. Nonetheless, there are times when this experience might be diminished. This could be due to malfunctioning parts or a buildup of calcium deposits. What causes the Bunn coffee maker to overflow? What leads to leaks in my Bunn coffee maker? In the article below, we’ll explore the reasons behind the overflow or leaks.

Bunn coffee makers are designed to offer a refreshing and delicious cup of coffee with every serve. Its efficient brewing temperature helps the coffee grounds to be extracted at their best. Unfortunately, the brewing experience will be tampered with by malfunctioned parts of the machine. Quite a few reasons can cause this. Below, we will be discussing some reasons in depth.

Why does My Bunn Coffee Maker Overflow?

The Bunn coffee maker can start overflowing due to various reasons. One of the major ones is calcium build-up. The coffee maker requires regular clean-up as maintenance. Without it, the coffee maker may start overflowing with water. 

Other reasons can range from problems with the decanter, brewing volume to the filter paper. We will be discussing the problems in the following for better understanding. 

Check The Decanter Before Brewing

Sometimes we tend to make more coffee than we do. It is perfectly alright. As we don’t know when we will need that extra cup of coffee. But if you didn’t consume it, make sure to throw it while making the freshly brewed coffee.

As the left coffee will create an overflow in the coffee maker. This is an unpleasant experience. So, to avoid it, remember to check the decanter before making the next batch. 

Check Coffee Maker’s Brew Volume

If the brewing volume is adjusted higher than expected then the coffee maker will most likely start overflowing. In this case, you also need to modify the spray head. If the problem is arising from incorrect brewing volume then after proper adjustment, the coffee maker will stop overflowing. 

Calcium Build-up in The Coffee Maker

The water you use in the coffee maker has a lot of minerals on it.  Months-long use without proper cleaning will accumulate the mineral deposits and buildup inside the machine. Hence, the coffee maker will be clogged. And there will be a backflow of water. And the result will be leaking and overflowing of water. 

To avoid the suffering of intense cleaning of the surroundings, clean the coffee maker thoroughly. And get rid of the build-up as early as possible. 

Paper Filter Can also Cause Overflow

The filter paper can slow down the water flow. If this happens then there will be an overflow. This can be prevented if the filter paper is changed to a different one. The brand Bunn encourages the use of an OEM coffee filter. So if your chosen coffee filter is not doing the work, then change it to the OEM one. 

But first, check if it’s the fault of the filter. For this, run a brewing cycle without filter or coffee grounds. If the overflowing doesn’t stop, then the problem relies on the other parts of the coffee maker.

How to Clean the Calcium Build-up?

Cleaning the calcium and lime build-up is very easy. All you have to do is to make a cleaning solution and run a brewing cycle. And the problem causing calcium build-up is gone. Here we will let you know how to do it step by step.

Step 1

Firstly, make the cleaning solution with vinegar and distilled water. We are using distilled water as there are no minerals in it. It will help to break the rusty build-up. Besides that, the vinegar and water ratio is 1:2. Then stir it nicely to mix it.

Step 2

Then pour the cleaning solution into the reservoir. And at the start of the brewing cycle, depending on the build-up you will decide on how many cycles you need. Normally 1-2 cycles are enough to do the work. 

Step 3

After that, throw the brewing water.  And do 3-4 cycles of brewing with clean water. This step is necessary to flush out the vinegar solution completely. Later you can enjoy making coffee in the coffee maker again without any disturbance. 


Why Is My Coffee Maker Still Overflowing?

First, check out all the above reasons for the water overflow. If not one of them is the cause, then maybe the problem is at the base of the coffee maker. If this is the case then try to see if the valves are working or not. Furthermore, see if the seal is broken or not. 

If the reason is the broken parts, then call for the maintenance guy. Furthermore, if the coffee maker is in the warranty period, then call the customer service. They will help you to replace the broken part.

Why Vinegar Is Used to Clean the Coffee Maker?

Vinegar is widely used because it is very accessible. We can easily find the white vinegar lying in the house. Besides that, vinegar is acidic. This acidic element helps to break the calcified build-up. Even though it has acidic properties, it’s not very harsh to the surface of coffee makers. So, it’s popular for cleaning the coffee maker.

How Many Times Should I Clean the Coffee Maker?

It is recommended to clean the coffee maker regularly after every use. Besides that, clean the removable parts with soapy water and a microfibre cloth. Furthermore, it is advised to do a deep clean once every 2-3 months. 


It’s a pity if the coffee maker loses its life expectancy due to negligence. As it is offering the best cup, we should be keeping up by cleaning it when required. This will ensure a rich flavor of coffee every morning. Hopefully, the above guide will help you to solve Bunn Coffee Maker overflow problem.

If the coffee maker leaking issue keeps persisting, it will be best if you call the customer service of Bunn Coffee maker. They will help you to diagnose the problem and offer you a possible solution. Sometimes you may even get a replacement if the coffee maker is under warranty.