Why is my gas water heater making a banging sound?

Author: Yessenia Schroeder  |  Last update: Tuesday, September 2, 2025

Banging/Rumbling: Banging and rumbling are among the most common water heater sounds. Typically, these noises can be attributed to excess sediment build-up. When enough sediment accumulates in your water heater tank, it may react with the heating element to create those little mini-explosions you are hearing.

How do I fix my water heater banging noise?

How to Stop the Water Heater from Knocking. In order to stop that knocking noise, you will need to flush your water heater. This will clear out the scale so that sediment no longer bangs against the inside of your heater.

Why is my gas heater making a banging noise?

Usually, too much static pressure in the ductwork. Static pressure is stationary pressure in a confined space (it's just like blowing air in a balloon). In this case, there's too much pressure pushing on your ductwork, causing it to expand and make a BANG noise.

How do you know if your water heater is about to burst?

7 Warning Signs of Water Heater Explosion
  • Leaking Pressure Relief Valve. ...
  • A Consistent Popping Noise. ...
  • Rotten Egg Odor. ...
  • Brown Water. ...
  • Gas Leak. ...
  • Improper Bad Installation. ...
  • Neglecting Routine Maintenance.

How do I stop my hot water from banging?

2 Answers 2
  • Have a section of pipe at the faucet that goes up and is capped. The trapped air creates a cushion which can solve the problem.
  • Or use a commercial water hammer arrester. These do basically the same thing and are smaller but cost more.

Is Your TANK Water Heater Making These SOUNDS

How do I stop my heater from banging?

Replace Your Dirty Furnace Filter

Heat causes the metal material to expand and push outward – when the cycle stops and the metal cools, it contracts and pops back into place, generating that loud banging sound that you hear indoors. In this case, the best solution is simply to change the dirty air filter.

What does a broken water heater sound like?

Here's what the most common water heater noises might mean: Crackling or Hissing Noise: A hissing sound could mean something is in the way of your water heater's heating unit. Popping Noise: A popping sound usually means there is sediment buildup inside the tank, likely from hard water or rust.

How long do gas water heaters last?

Average Lifespan Of A Hot Water Heater

With regular inspection, draining, and flushing, you can expect a gas water heater to last anywhere from 8-12 years and an electric water heater to last anywhere from 10-15 years.

Why does my heater thump?

The most common reason for an unbalanced blower wheel is a lack of maintenance. By that, we mean that the furnace filter either hasn't been changed in a long time or there is no filter. In either case, dirt, crud and pet hair builds up on the blower wheel. This puts it out of balance, causing obnoxious banging noises.

Why does my gas pipe make a banging sound?

When gas lines, tanks, or appliances give you a pinging or knocking sound, it's likely due to problems with the air/gas mixture. When this mixture is uneven flow in the gas lines will not move evenly (similar to the water hammer noise you can get when there's air in the plumbing).

Should a gas heater make noise?

Despite it being normal for a gas heater to make little noises, you should be a little worried and repair your gas heater if you think that the sound being produced is quite abnormal, for instance, loud noise when turning off.

Is it bad if my water heater is knocking?

Signs Your Water Heater Needs Repair

If any of the following is happening along with the knocking, it's time to call Schaafsma: Knocking, banging, or popping sounds can mean sediment buildup, water hammer, or heat trap issues. Inconsistent water temperatures or a lack of hot water.

Why is my gas hot water heater making a popping sound?

Is your water heater making a popping noise similar to how it sounds when your microwave is cooking popcorn? That popping noise probably means there's sediment at the bottom of your water heater tank. The solution? Simple—the tank just needs flushing.

How often should I flush my water heater?

Most homeowners should flush their water heaters every 6 months or so, but if you have extremely hard water, you may want to do it more often. Flushing your hot water heater could be necessary as often as every few months depending on the mineral content of your local water supply.

How do I know if I need a new gas water heater?

If your hot water is no longer coming out hot or is only hot some of the time, it may be time to replace the heater. Sometimes the devices and mechanisms inside will wear down or break, causing your heater to stop heating. In some cases, this may require a simple repair.

How to tell if your anode rod is bad?

Poor water heater performance can sometimes stem from an anode rod that's overdue for replacement. If you notice signs of poor performance, such as discolored or rusty water, sulfuric or rotten egg smells, popping sounds from the tank, or high heating bills, inspect your water rod to determine if it needs replacement.

How do you know if your gas hot water heater is broken?

Noisy or making strange noises.

Most hot water systems do make minor noise as it heats up the water in your home. However, strange, loud noises such as hissing, popping, cracking or banging are uncommon. If you hear a hissing sound coming out from your hot water system, it most likely means the tank has burst.

Why does my gas water heater make a banging sound?

Banging/Rumbling: Banging and rumbling are among the most common water heater sounds. Typically, these noises can be attributed to excess sediment build-up. When enough sediment accumulates in your water heater tank, it may react with the heating element to create those little mini-explosions you are hearing.

What are the signs of a water heater going bad?

Water heaters show several signs of going bad, including lack of hot water, temperature fluctuations, decreased water pressure, strange noises, rotten egg smell, visible leaks, rusty or discolored water, and increased energy bills. If your water heater is over 10 years old, it may be time to consider a replacement.

How to drain a gas hot water heater quickly?

How do you drain a water heater?
  1. Step 1: Shut off the water to your water heater. ...
  2. Step 2: Turn off the power to the water heater. ...
  3. Step 3: Give the water time to cool off. ...
  4. Step 4: Attach a hose to the drain valve. ...
  5. Step 5: Turn on a hot water faucet. ...
  6. Step 6: Open the drain valve (let the water out)

Will water hammer go away on its own?

Water hammer rarely goes away on its own; it's a serious plumbing problem you should address. Pipes can sustain damage from repeated impact, resulting in leaks or burst pipes.

What is the banging sound in my pipes?

What causes plumbing pipes to make a banging noise? If you hear a vibrating, banging or pounding noise when taps are turned on or off it's usually due to hydraulic shock in your plumbing pipework. Hydraulic shock is more commonly known as “water hammer”. The banging noise you hear is the result of vibrations in pipes.

What are the warning signs of water hammer?

Also called hydraulic shock, the signs of water hammer include a loud thumping or “hammering” noise from pipes carrying fluid and moderate- to heavy vibrations along the pipe system. Its impact can range from mild or undetectable vibrations to severe and very disruptive pressure shocks.

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