Hot Water Heater Making Loud Noises

Why is my hot water heater making loud noises? This is an everyday question that has been bugging most homeowners. It could be a high-pitched noise, a hissing noise, knocking, or even a siren-like noise. Sometimes it is just a light sizzle or, worse, a head-splitting rumble.

They all point out one thing; your hot water heater is having problems. But what could be the cause of such loud noise? What are the possible remedies to salvage the situation?

Well, with such noises, you are clearly having nightmares for a shower. You are cleaning with cold water, and chances are your home isn’t heating up as you would wish.

It needs to stop! Obviously, you can’t go on like this given the importance of hot in your home.

Unfortunately, it is a common problem, but solutions are imminent. Therefore, instead of spending so much time crawling the internet for possible reasons for your hot water heater problems, I suggest you continue reading along to find out all the possible causes and proposed remedies.

Common hot water heater noises

  1. Hot Water Heater Making High Pitched Noise

I can’t even explain how freaked out I was the first time I heard the high-pitched noise coming from my water heater. For one, I thought my house was about to blow up. But that wasn’t the case. Apparently, there was a pressure build-up due to incoming hot water, and the pressure release valve failed to open.

Another reason for high-pitched noise is sediment build up inside the tank, often due to unfiltered hard water. Usually, it builds up at the bottom of the tank forcing the heater to use more energy when heating the water. As a result, it releases the high-pitched noise.

Here is what you need to do;

  1. Flush the water heater

When the water inside the tank is heated, dissolved minerals usually settle at the bottom of the tank. Over time, they form a thick sludge which eventually hardens to create sediments.

It is necessary to regularly flush the water heater to get rid of the deposits before the situation worsens.

Some chemicals help in descaling the tank since water alone can be relatively inefficient.

Check out this Flow Aide System Descaler .

  1. Fix the pressure relief valves

Sometimes, the high-pitched noise is because the pressure relief valve failed to open. It is a safety device that needs to be fixed as soon as possible or risk blowing up the basement.

You can either manually open the valve, or if the problem persists, you change the valve altogether.

Check put this pressure relief valve.

 2. Hot Water Heater Making Knocking Noise

Whether it is your car or any other piece of machinery, a knocking sound is never a good sign. If you experience the same with your hot water heater, you need to fix it real soon or run the risk of replacing the entire system.

You obviously don’t want that. So, why is the hot water heater making a knocking noise?

The main cause of knocking noise from your water heater is sediment build-up, also referred to as limescale or just scale. When the minerals settle at the tank’s bottom, they form a sludge that traps water beneath.

As it heats up, the water boils and produces an explosive bubble as it spurts through the scale build-up to produce the knocking sound.

Here is what you need to do;

  1. Drain flush your water heater

The only viable solution is to eliminate the lime scale by drain flushing the water heater in such cases.

Here is how to go about it;

Turn off the power supply, shut off the incoming cold water, and turn on one faucet in the house.

Open the temperature relief valve, connect a hosepipe to the drainage spigot at the bottom of the tank, and turn it on. Once everything is set, run cold water into the tank by opening the cold water valve until the water from the drain is clear, then turn it off.

By doing so, you would have successfully drained your water heater tank. However, sometimes the sediments are so glued to the tank and water alone cannot remove the residue. Using CLR cleaner will dissolve the sediments and remove rust from the heater.

Check out CLR PRO Calcium, Lime, and Remover.

3. Hot Water Heater Making Hissing Noise

So you’ve noticed that your hot water heater is making hissing noises. Sometimes it gets too loud, while other times, it is bearable. But is it really bearable? You see, such noise from your water heater is reason enough to raise the alarm. Worst case scenario, you could lose your heater or incur costly repair expenses.

First, you need to understand why this is happening and find out if there are any possible solutions. Let’s have a look at some of the reasons and possible solutions.

  1. Condensation

When water heaters are refilling, you will often hear hissing sounds. If this is the case, there is probably no reason to raise the alarm as there is a reasonable explanation. When you wash dishes with hot water, you use up the water in the tank. The tank then fills up with cold water.

With cold water in the tank, hot air condenses on the outer surface and comes into contact with the hot tank; the evaporating moisture then produces a hissing sound. So if you hear such noises immediately after you take a hot shower, it could be just condensation taking place.

  1. Sediment build-up

The sediment build-up is one of the primary reasons why your hot water heater is making loud noises. Often you won’t hear the hissing noises alone. Sometimes, there will be high-pitched noises, rumbling, or even popping noises.

It is particularly rampant in areas with hard water. To tackle this problem, drain flushing the water heater tank to remove the scale is necessary. However, sometimes the damage is pervasive, and you will need to replace the entire water heater.

  1. High-temperature settings

For this case, you will hear hissing noises coming from the pressure valves rather than the water heater itself. This is a clear indication that the water temperatures are too high and pressure is building up. In typical situations, the pressure valve will open and release the excess pressure, then close again.

However, in unlikely situations, it will remain open, continuously releasing pressure. Thus producing the hissing sound incessantly.

You need to fix this problem as soon as possible since too much energy is going to waste. Lower the heating temperature to about 120 degrees which will consequently lower the pressure build-up in the tank.

4. Hot Water Heater Making Siren Noise

We often overlook the importance of the water heating system until it starts to malfunction. For instance, when your water heater starts producing siren noises. If this happens to you, you need to establish the cause and devise a possible solution.

So why would the water heater make siren noises?

  1. Your tank is cracked

Now, if you don’t regularly check your water heater or call up maintenance regularly, you may never notice when your tank cracks. The main cause is usually rust that weakens the metallic surface. When air enters and escapes the tank, it produces siren-like noises that intensify when you heat the tank heats up.

The only viable remedy for this problem replacing the water heater tank.

  1. Loose Pressure Relief Valve

The pressure drain valve is a safety device that relieves excess pressure build-up inside the tank. When temperatures and pressure exceed the required standard, the valve opens. However, it also happens that the pressure valve gets worn out and loosens. With such a valve, even a slight increase in pressure and temperature will produce siren-like noises.

You can’t continue having such a valve as it has already proven inefficiency. The best thing is to replace it with a new one.

Check out this pressure relief valve.

  1. Worn out Drain Valve

At the bottom of the tank, a drain valve usually releases sediment that builds up over time. Eventually, due to the corrosive nature of sediments, the drain valve wears out and loosens.  A loose valve will let air slip by producing siren-like noises.

If you have such a situation, you might want to replace the drain valve with a new one.

Bonus tip: Drain flush your water heater after every 6 months to prevent overtime sediment build-up.

Check out this Water Heater Drain Valve.

5. Hot Water Heater Making Noise like Running Water

It is normal to hear running water inside the tank when it is refilling. However, if the noise persists when the tank is filled up, you may be having a leak, or one of the pipes is broken. For such a case, you will need a professional to help you out, or you can try and find the leak yourself.

Turn off all the water taps and carefully place your ear against one of the hot pipes. If you hear the water flowing, it means the water is leaking somewhere. You may also notice a shortage of hot water in the tank. Have a professional find and fix the leak for you.

Hot Water heater Making Loud Noise: Frequently Asked Questions (FAQs)

Q: Can a water heater explode?

Unfortunately, water heaters explode, and it is usually frightening. The primary cause for such an explosion is too much pressure and temperature build-up inside the tank, often because the pressure relief valves failed to open. Also, a gas leak and heavy limescale build can cause the water heater to explode.

Q: How do you fix a noisy water heater?

First, you need to understand the cause of the noise. It could be leakage from one of the valves or the result of heavy sediment build-up. Once you know the cause, it becomes easy to come up with a practical solution. If it is sediment build-up, all you need to do is drain flush the tank.

Q: Is a noisy water heater dangerous?

Unusual noise emanating from your water heater could be a sign that it is having some problems. Whether it is dangerous or not depends on what is causing the noise.

For instance, when you hear knocking sounds because of sediment build-up, that calls for immediate action. Heavy sediment build-up can destroy the water heater rendering it useless.

 Bottom Line

It is not strange for your hot water heater to make loud noises. However, some noises are telltale signs that you are about to lose your machine.

It calls for alarm when you hear high-pitched and knocking noises as they represent heavy sediment build-up that is slowly destroying the water heater. Run regular maintenance on your water heater to prevent such from happening.

How to drain a water pressure tank