4 Reasons Why Your Water Heater is hissing


Nowadays an essential part of any home is a water heater that ensures you have hot water every time you need it, but when your water heater is making hissing sound, it can cause a lot of chaos.

Water heater makes your life quite easier and is promising to be a reliable companion. To ensure it works perfectly, you need to take good care of it.

water heater

If you experience any issue, you must pay attention to that. Sometimes, a water heater makes a hissing sound. There could be some reasons for that.

In this article, we have included possible reasons for this and how to solve them. Let’s have a look.

Possible Reasons Why Water Heater is Making A Hissing Sound

After extensive research, we have found 4 reasons why your water heater could be making a hissing noise and those are;

  • A build-up of residue and sediments
  • High water temperature
  • Condensation
  • Fractures or leaks in the tank

At first, these problems do not seem to be severe and should not cause immediate concerns. As we will discuss these reasons in more detail, we will let you know whether you should be worried and if you need to contact a professional for more help or not.

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1. A build-up of Residues and Sediments

The reason for a build-up is that as you heat water in the heater, dissolved minerals such as magnesium and calcium crystallize over time and settle at the bottom of the tank.

This daily build-up results in the formation of sediments.

If you are living in areas where you use hard water, then this extra accumulation of sediment would be more common as hard water contains an excess amount of various minerals including magnesium and calcium.

Now you will be thinking that how it is linked with the hissing sound of the heater.

With the sediment formation, water gets stuck between the layers of the sediments and when you turn on the heater, the water in it begins to heat, becomes extremely hot, and begins to boil.

Thus, the boiling water evaporates into steam and as a result, it produces a hissing or sizzling noise.

What to do?

The only solution to this problem is to flush your water heater to remove the build-up of sediments at the bottom of the tank.

The task is very simple and you can do it on your own but if you do not want to do yourself you can ask a professional for help.

If you are interested in removing the sediment build-up on your own you can get help from different tutorials that can help you through the entire process.

2. High Water Temperature

If you have set the output temperature of your water heater too high such as 140 degrees or higher then the temperature and pressure (T&P) valve will open automatically to offset the additional internal pressure that has been created.

As a result, your water heater will produce a hissing noise. You must make sure you have not set the output water temperature above the limit.

Here the role of the T&P valve is critical. It is used with a water heater for this specific purpose. Just in case the water temperature reaches a dangerous level, it will open automatically to expel steam and during this process, the extra internal pressure is released to balance the internal temperature. 

This level of heat differs from heater to heater.

What to Do?

The ideal solution to this problem is keeping the temperature of the water heater to around 120 degrees. After a T&P valve gets opened, it is no longer beneficial and should be replaced.

If such has happened with your water heater then you should seek professional service

3. Condensation

The most common cause for a water heater to produce a hissing or sizzling noise is condensation. It happens when cold water fills up the tank of the heater producing small puddles of condensation to build outside the tank.

Over time, the water droplets will run down and come in contact with hot parts of the water heater. This will lead to a water heater making a hissing sound.

What to Do?

A common cause for condensation may be that the water heater is quite small for what the hot water needs of the households are.

You might need to think about adding a large water heater or finding alternatives to restrict the use of hot water in your house.

4. Fractures or Leaks in The Tank

If the tank of your water heater has fractures or leaks, then it is obvious that it will make a hissing or sizzling noise.

If there is a leak or even small fracture, water will escape throughout heating and reach the hot surfaces and as a result, a hissing sound will be produced.

Many situations can lead to a leak such as a loose valve that requires tightening or a corroded tank. If the tank is corroded, then you must replace the entire water heater as soon as possible.

If you hear the hissing sound without drawing a huge volume of water, then it is an indication that your tank probably has a small leak in it.

If you see large water puddles are settling beneath the tank, then it is an indication that your tank has a large leak and should be addressed immediately before it is too late.

If such happens with you, you should turn off the water supply to the heater and switch your water heater to pilot or vacation while you wait for the help to arrive. Try to dry the water around the tank and check for leaks.

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What to Do?

When you realize that your water heater is leaking, contact a professional. Do not think to repair your leaking tank as it can be dangerous.

The only way to solve this problem is to replace the entire water tank. You should seek immediate help as soon as you notice a leak. Do not wait as the leak might get bigger and lead to water tank bursting.