Is Your Water Heater Making A Hissing Noise? Here’s What to Do.

Chances are you’re here because your water heater is making some weird noises. We get all kinds of calls about weird water heater noises, ranging from water heaters whistling, to water heaters sounding like they’re full of rocks, and yes, we even get calls about water heaters sounding like hissing snakes. If your water heater is making a hissing noise and you don’t know why, you’ve come to the right place!

If your water heater is hissing, where do you start?

First, you need to determine the possible causes of the hissing. After that, you’ll need to figure out what to do to make the noise stop (hopefully forever). Keep in mind that the appropriate action depends on how your water heater is behaving. If at any point you feel that your water heater is not working properly, TURN IT OFF and call a professional for help.

Possible Causes

What could be the reason that your water heater is making a hissing noise? There are several potential culprits that you’ll want to investigate – either by yourself or with the help of a professional.

1. Condensation

Condensation can be a reasonable and normal cause of a hissing water heater. What happens is that as cold water fills the water heater tank, condensation builds up on the outside of the tank itself. As the condensation rolls off, it can hit hot parts of the water heater, and in doing so will produce a sharp hissing sound.

2. Temperature

If the temperature of your water heater is set too high, you might also hear your water heater hiss. The temperature and pressure (T&P) valve will automatically open when the pressure within the tank gets dangerously high. The higher the temperature, the higher the pressure, and when the T&P valve opens, the sound of the pressure releasing can sometimes let off a hissing sound.

3. Sediment

If you live in an area with hard water, then you’re probably familiar with sediment buildup in your tank. As sediment builds up in the tank, the minerals that are deposited at the bottom of the tank will actively trap water bubbles. As those bubbles boil and turn into steam, they will make a hissing noise.

4. Leaks

No one ever wants to hear that their water heater has a leak, but these too can be the cause behind your hissing water heater. If there is a leak in your tank, even just a small one, it will release water. As the water hits the hot surface of the tank, it will boil and sizzle, letting off what could be described as a hissing noise.

What to Do About a Hissing Water Heater

So you’ve established that you have a problem. Now what do you do about it?

‌• Check the Temperature and Pressure Valve

As mentioned above, the T&P valve could be opening in order to let off excess pressure. Check to make sure your water is set to a reasonable temperature. If it already is, then you’ll need to have someone inspect the valve further to make sure it is working properly.

‌• Flush the Tank

If sediment build up is the issue, flushing the tank should do the trick. You can flush the tank yourself, or hire a professional to do it for you. Removing the sediment build up should also remove the hissing water heater problem.

‌• Turn off the Water Heater and Call the Pros

It’s OK to admit that you don’t have the knowledge needed to solve the problem yourself. If you are face to face with a hissing water heater that just won’t quit, you should turn off the unit and call a professional immediately.