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Why Is My Hot Water Heater Making Noise Like Water Running?

Although water heaters offer great convenience, they can be frustrating when they start making strange noises. This can make it difficult for you to concentrate on work, study, or anything else.

While some of these noises are harmless, a water heater making a noise like water running usually indicates a leak somewhere.

Still, you must be sure about the problem before wasting money calling in an expert. So the first step is to diagnose the water heater to find the root cause.

Read on to learn why your hot water heater is making a noise like water running and what steps to take.

Why Is My Hot Water Heater Making Noise Like Water Running?

Tank Containing Sediment & Mineral Deposits

It’s normal for you to hear water running when you switch on your heater. This indicates that cold water flows into the tank to replace the hot water drawn into your sink and tub.

However, if you hear water running when you aren’t using any tap, it’s often a sign of a leak. Usually, you will notice moisture on the floor directly under the heater. This moisture seeps out from behind the wall and gathers in a spot.

However, it’s possible not to find any leak. In that case, the noise may be due to a faulty T&P valve.

How to Diagnose a Hot Water Heater

You can follow these steps to diagnose your water heater.

Step 1. Inspect the Water Meter

The water meter measures the volume of water you use in your building. To inspect it, you should first turn off all the taps supplying water to your heater. Then note the assessment on the pressure gauge and the reading.

Next, turn on the taps and observe the reading on the pressure gauge again. If the difference is high, it indicates water comes into your heater with an extremely high velocity. The sound of the rushing water may be responsible for the noise.

Step 2. Check the Pipe

As we’ve mentioned earlier, a leak is the most likely cause of your water heater making a noise like water running. Whether you notice a water puddle under your heater or not, you should first turn off all the taps.

Then, place your ear close to the pipe that supplies water to the heater. If you detect a running water sound, you have a pipe leak or a broken pipe.

You can also inspect all the pipes connected to the house. Ensure you check the toilet pipe, too, to see if it’s broken. An overflow may be responsible for the running water sound.

Step 3. Examine the T&P Valve

The T&P valve is designed to open and release pressure inside the tank whenever the pressure or temperature gets too high. However, a faulty T&P valve causes water to drain from the tank. This may be responsible for the running water sound, especially if the T&P connects directly to the drain.

If your plumber discovers an issue with the T&P, you’ll need to repair or replace it.

How To Fix Your Water Heater

Crackling, Sizzling, Hissing, or Popping

After detecting the issue, the next thing is to call a professional. A problem like this is not something you can fix on your own, so put a call to your local plumber and describe what you have observed.

Although each plumber works differently, here’s a breakdown of how it should go.

Step 1. Turn off the Heater

Before beginning core repairs, your plumber will first turn off the water heater’s electrical power. If you use a gas-powered heater, turn off the gas valve.

Step 2. Shut the Water Valve

Shut the water inlet valve to cut off the water supply inside the heater tank. This also helps to eliminate some possible causes of the noise.

Step 3. Release the Tank Water

Your plumber may attach a water hose to the drain valve to release the water in the tank. They may also transfer the water to a bucket instead.

Step 4. Open the Faucet

Opening a faucet connected to the heater helps to get air inside the tank. This makes the draining procedure easier.

Step 5. Flush the Drain Valve

The drain valve is where sediments settle, so the plumber will open it to flush it. But the water from the faucet is usually boiling, so you must wait for at least thirty minutes before opening the drain valve.

You’ll need about three to four gallons before the drain valve becomes clear.

Step 6. Fix the Underlying Issue

If the problem is a leaking pipe, your plumber will break the wall to replace it. However, if it’s a T&P valve, they will open the heater tank to inspect it.

How long your repair takes depends on the severity of the underlying issue.

Other Water Heater Noises and What They Mean

Here are some other noises that water heaters may make to signify a problem.

Banging or Hammering

A hammering or banging sound occurs when there’s a pressure surge. This happens whenever the water is forced to stop or change directions suddenly.

A water hammer can happen due to a leak in the T&P valve. If it’s not resolved quickly, it can cause an expansion and deformation of the water tank and cause your pipes to explode.

Plumbers usually install a pressure-reducing valve or water hammer arrestor to address it.


Rumbling is one of the most common sounds people complain they hear from their water heater. It’s usually caused by severe sediment build-up in the tank.

This is more likely if you live in an area with hard water. The mineral deposit from the water settles in the water heater tank, so when hot water heats and expands, it has to push through the sediments to reach the top of the tank.

This causes those sediments to shift against the sides and bottom of your water heater, leading to the rumbling sound.


This can also be a result of sediments. The heat exchanger inside the water tank helps to heat water to a desirable degree. When mineral deposits, sand, and debris build up on the heat exchanger, they thicken and form limescale.

So, as water is heating up, it gets tracked with the sediments on the lower part of the heat exchanger. This traps moisture steam between the mineral crust and the hot metal. A popping or cracking sound will follow as the water boils.

You can always open the drain valve to release the water and flush out the sediments. But if it looks serious, it’s best to call your plumber.

Sizzling/ Hissing

You’ll usually hear a sizzling sound when your heater leaks on the heat exchanger. Think of how a pot sizzles in because you are boiling water on the surface of a metal. This is a similar situation.

The heat exchanger is metallic, so if your heater drips water on the surface, the simulation will dry up the water and create that sound.

This can be dangerous. So, it’s best to disconnect your water heater from the power surge. Then, see if you’ll be able to detect where the leak is and call your local plumber.


If it feels like your heater or the room vibrates when your water heater is working, you probably have a loose heating element. So, you’ll need to tighten the heater.

A lighter vibration can happen when cold water mixes with hot water in the tank, while a vibration can occur due to sediment build-up.

Also, your water heater can vibrate if the water pressure is too high. In this case, adjust your water pressure to between 40 to 60psi.


A humming sound can occur as the two heating elements in your water heater perform their regular operations. This often happens because the heating elements are not tightly screwed in place.

However, a humming sound is the least problematic sound from a water heater. You can hear it from even a new installation, but there’s usually no cause for alarm.

Simple Water Heater Maintenance Tips

Regularly maintaining your water heater is the best way to prevent all the issues that may cause noise. It will also help to extend the life of the heater.

Here are a few maintenance tips you should practice.

  1. Install a water softener on the cold water feed line where cold water enters the house. This will help prevent hard water sediments from entering your tank.
  2. Tighten the heating element when you notice any vibration when your heater is on. It’s best to do this once a year.
  3. Adjust your tank temperature to 110°F. This will extend its life and reduce noise-causing pressure.
  4. Flush the heater tank annually with a deliming solution. You can call your local plumber if this seems too complex.
  5. Install a thermal expansion tank to prevent water backflow and water pressure fluctuations.
  6. Run out the water in your heater quarterly to prevent sediment build-up. You can place a bucket under the tank’s drain spigot, open the tap, and run the water until it’s clear.

Final Thoughts

Suppose your hot water heater makes a noise like water running; you’ll need to inspect the pipes connected to it for leaks. You should also check the T&P valve for faults.

But if there’s a sound your water heater makes that we didn’t cover, you can shoot us a comment below. We will be happy to answer your questions.

Don’t forget; to solve your water heater issues:

  • Listen closely to identify the specific sound;
  • check your meter and pipes;
  • switch off the heater and drain the valve;
  • call your plumber to fix the underlying issue.

12 thoughts on “Why Is My Hot Water Heater Making Noise Like Water Running?”

  1. My heater pops when using hot water. Just draining it causes it ti pop. Its not hot water boiling up thru sediment. The cold water comeing in does it- but why.

  2. My old water heater used to leak, and I was desperate about it because I thought that having water and electricity together can cause a lot of problems. Since then, I’ve switched my heater thanks to my old friend’s advice I am also putting some time into maintaining it. Since I started doing this regularly, I have much fewer problems with it.

  3. from a brand new water heater, I have a low moaning sound that starts low and gets louder then dies down and stops within about 3 seconds as the water heater burner starts to get hot.

  4. My water heater makes a sound while running but only while it runs, it’s like water sound. Is it normal for water heaters to make noises while running, because other than that it’s silent.

  5. My water heater, an old wall unit is making crazy noises.
    I opened the cover and saw a new piece of pipe attached just before the water comes up. No other unit has this addition.

    My X husband is harassing me remotely – PC, TV hidden cameras, and I tent to think he is behind this. ( it’s only in my bedroom)
    Every 2 hours of day and night the heater goes Boom Boom that I can’t take without ear plugs. ( I believe that the super intendant is involved) what should I do?
    If you can text instead of email that would help, he controls my email also.

    • Gania, you shouldn’t have to live life as a prisoner. He sounds like a control freak and things will NOT get better. Most likely it will get worse as time goes by. Does he yell loudly? Does he slam doors and throw things? Or, does he intimidate you with his hands. Get out now. screw the water heater. Not the good way to live. You deserve to be loved not possessed.
      May you find your peace in life.

  6. I wasn’t aware that we’re supposed to flush our water heater system as often as we can until you mentioned it. This explains why we kept on hearing sounds from it that we have never heard before and had made me worried for a couple of days now. Maybe seeking assistance from experienced plumbers can also help us diagnose and fix the issue better.

  7. My fan on my water heater is making a buzzing sound? I unplugged it not sure what to do!!

  8. My house vibrates constantly i’ve notice it does when the hot water tank is starting up its disturbing my sleep. it sometimes feels like earthquake. what should i do?

    • When open water making a noisy sound how to stop tap water making sound

  9. Hey, you used to write magnificent, but the last several posts have been kinda boring… I miss your great writings. Past few posts are just a bit out of track! come on!


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