Water Heater Flame Sputtering [8 Reasons To Fix]

If you own a water heater for a very long time, you must be familiar with various issues related to the water heater. Among them, water heater flame sputtering is one of the most common problems that every owner experiences at least once. 

But wait, can you determine the actual cause of sputtering? Well, it’s not an easy task because there are many factors related to this problem. In this article, I will split out each factor and will try to give you the solution to the specific issue, too. 

So, stay with me to know about this unusual occurrence in detail.  

Water Heater Flame Sputtering: A Detailed Discussion

There are many factors that create the sputtering of water heaters. When you know the causes of sputtering, it will be easy for you to determine what is wrong with your heater. Here I am going to share the causes of water heater sputtering with solutions of each:

1. Restricted Burner Port:

The most common cause of sputtering is a restricted burner port above the burner head. The burner ports, secondary air shutter are sometimes filled with lint or dust.


It is not a serious issue. Usually, a simple cleaning can eliminate the heater problem. Remove the burner assembly, clean the burner and its head. After that, reinstall it to cure the issue. 

2. Water Heater Shooting Flames:

Water heater flame fluttering, flame distortion, failure of gas combustion, black soot formation are also responsible for the sputtering of the water heater. Soot alludes to major problems of the water heater that should be determined and treated by experts. 


You should not fix it by DIY, as it is not a normal condition. If you notice a soot present in the firebox, consult with a licensed plumber or professionals of the gas utility. 

3.Water Inside Firebox:

If the water heater is older than five years, the firebox may have water inside it. It occurs due to tank leaking. When the tank leaks, water flows to the vent or to the firebox. 


You will need to replace the water heater in this situation. 

4. Clogged Aerator:

Clogged aerators also can cause sputtering water. There is a tap on top of the heater that filters debris from the water. When too much dirt clogs the filter, it will produce sputtering. The debris usually comes from the material dislodging from the joints of plumbing. 


To prevent sputtering, you will need to clean the aerator once a month. You can easily remove them by spinning them counterclockwise. When the aerators are removed, clean the debris using soapy water and rinse it.

5. Air in Water Lines:

Air in water lines creates a sputtering sound in the water pipe. It is a common problem to sputter faucets with air. Because of air bubbles stuck in the water pipe, a gurgling sound comes from the line. 

In winter, this happens because of extremely cold temperatures. Also in summer heatwaves, this sputtering sound can be heard. A slit stir can cause this problem. 


Temporary sputtering problems can be solved by flushing the line one or two times with cold water. If two or more faucets face this problem, you probably have damage to your water system. 

Flushing the pipes won’t work this time. In this situation, you better not try to clear the lines but instead call the water utility to look after the problem.

6. Faulty Water Heater:

If the water heater sputtering remains even after replacing the cartridges, it may be due to the faulty installation of the water heater. Usually, the manufacturer does the installation process. But, sometimes it may cause serious issues. 


You should look for professional help because faulty installation needs to be repaired immediately. 

7. Damaged Valve Cartridge:

If cleaning the aerator does not eliminate the sputtering, you will probably need to check the valve cartridge. If the cartridge has an issue, it can create sputtering. 


Remove it. The removing process won’t be the same for different types of valve cartridges. It is recommended to follow the owner’s manual. 

8. Buildup of Sediment:

Sediment is also one of the most common causes of sputtering water. You will know the detail about sediment buildup in the next section:

Sputtering Water Heater Flame Due to Sediment Buildup

When water contains a high amount of magnesium, calcium, iron, and other mineral salts, it is known as hard water. Over time, these heavy minerals settle at the bottom of the water tank. When too many mineral salts become hard and settle on the surface, it creates sediment. 

Effects of Deep Sediment in a Water Heater Tank:

Usually, mild sediment does not do any harm to the water heater. But if the sediment is left untreated, the layer of sediment increases and can cause several issues. They are—

  • Sediment slows down the transfer of heat to the water leading to overheated heaters. An overheated heater may damage the water tank.
  • In case of an electric water heater, sediment sometimes covers the heating element that can burn out the element. 
  • Sediment also can displace the tank water. As a result, you won’t have available hot water that normally you can get from the heater.
  • The efficiency will be decreased and thus the electricity bill will be increased. 


There are three possible solutions you can choose to prevent sediment buildup—

1. Slowing the Buildup:

Take a bucket of water from the tank and dump it once every three to four months. Fill the bucket by the drain valve. Be careful as the water is hot, it can burn your skin. Doing this frequency may leak the valve, so keep an eye on that.

2. Water Softener:

You can install a water softener that will eliminate the sediment from the water tank.

3. Flush the Water Tank:

Flush out the sediment from the water heater tank once or twice a year. You can flush it by yourself, or call a professional plumber.

How to Flush Water Heater Tank

Flushing the water tank is an easy process. Just follow the steps properly and it will be done.

  • In case of a gas water heater, turn the control to pilot, and in case of electric water heater, turn off the heater.
  • Turn off the supply of water. You can spin the cold water ball valve to clockwise or pull cold water above the hot water. 
  • Wait for 30 minutes and let the heater cool down.
  • Connect one end of a hose pipe with the drain valve of the water heater. 
  • Place another end of the hose pipe at the basement drain.
  • Flip the pressure relief valve up. 
  • Open the drain valve of the heater.
  • Drain the water completely. 
  • Flush out remaining sediment with cold water.
  • When the cold water starts running clear, it indicates the sediment has been eliminated completely. 
  • Close the drain valve, fill the tank with cold water. 

When the tank is filled with cold water, the flushing process is done. Now you can turn the heater on again. If you leave the sediment untreated, it will create a bigger problem in the future. It can rust the bottom of the water tank and leak the lower surface. 

As a result, you will hear a rumbling sound. When the tank starts leaking, you will need to replace your water heater.  


Why is your water heater bubbling?

If your water heater starts bubbling, it may be due to the minerals and sediment buildup, or due to rust in the tank. The cold water sits at the ground of the tank and hot water stays at the upper surface. When your heater has a lot of scaling, the heated water starts to rise up and creates bubbling.  

Can air in water pipes cause damage?

Yes, it can cause damage. All the fuel-burning machines produce harmful byproducts like carbon monoxide, methane, etc. If you have a faulty ventilation system, or, water pipes contain air, it will contaminate the water.

Can a hot water heater cause air in pipes?

If you notice any issue only with the water pipes, it may be having air in the heater. Sometimes there is air in water lines after changing the water heater, too. If the water heater has not been purified for a while, air can enter the pipes. The trapped air often fills the pipe within a couple of hours.


It is important to determine the actual cause of water heater flame sputtering. Otherwise, you won’t be able to fix the problem.

Also, you need to know whether you can fix it by yourself, or you need to consult with professionals. It is not wise to take risks when the condition of the water heater is hazardous. 

About William

William is the founder of Fireplacehubs.com. He has real life practical skills in fixing smoker & heating appliance issues. He loves to share his knowledge & helps others in fixing their appliances & saving their money. William firmly believes that anyone can repair his or her unit with the correct guidance & knowledge. See more at about us.

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