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Why Is My Water Heater Whistling? A Minnesota Plumber Answers


“Ahh! What’s that loud, high-pitched whistle coming from my water heater?”

Besides being annoying, a whistling sound could be a signal that something’s not working right in your water heater.

If you hear a whistling noise from your water heater, you likely have one of these 4 water heater problems:

  1. High pressure in the tank
  2. A loose drain valve
  3. A worn hot water outlet
  4. A cracked tank

In this article, we’ll go into more detail about each of these water heater problems and how you can solve them.

But first, let’s look at what you should do first if your water heater whistles…

Need a water heater repair ASAP? Our team of skilled plumbers are standing by to help!

What to do if your water heater whistles

Follow these step-by-step instructions:

4 whistling water heater problems (and how to fix them)

  1. Turn off gas or electricity (depending on what type of heater you have).
    • Gas: Twist the dial on the top of the thermostat to the OFF position. Then close the gas shutoff valve, which you’ll find on the gas line directly behind the water heater.
    • Electric: Switch the circuit breaker for the water heater to the OFF position.
  2. Turn off the water supply. The main water shutoff valve is usually located directly above the unit. Turn it clockwise to shut it off. If water keeps flowing, turn off the main water valve for the entire house.
  3. Look for signs of corrosion or moisture under your water tank. If you see those signs, it could point to a leak, which you’ll want to know about sooner than later.
  4. Call a professional. In the following section, we’ll explain why you’ll need a professional’s help.

4 whistling water heater problems (and how to fix them)

#1: High pressure in the tank

During normal operation, heat and pressure build up inside the water heater tank. If the pressure inside the tank ever reaches dangerous levels, the pressure release valve (also called the TPR valve) will open slightly to let air escape the tank, which reduces pressure. When air escapes the tank, it can make a whistling sound.

If you only hear the whistling sound on rare occasions, then you don’t need to be concerned. However, if you hear the whistling noise frequently, it could mean your water heater is battling constant high pressure, which is bad for your water heater and potentially dangerous.

High pressure can be caused by the following issues:

Solution: If you hear the whistling noise frequently, you should contact a professional to diagnose and fix the problem ASAP.

#2: A loose or leaky drain valve


At the bottom of your water heater tank, you’ll find a drain valve. A drain valve allows you to empty your tank of water and any built-up sediment. If your drain valve comes loose or leaks, air will enter into the tank and cause that whistling sound.

Solution: Check to make sure your drain valve is closed tight all the way with no leaks.


As time goes on, your cold water inlet and hot water outlet (pictured above), may wear out and corrode. When these connections wear down, they create a whistling sound.

Solution:Contact a professional to replace your cold/hot water outlet.

#4: A cracked tank

Solution:Contact a professional to repair/replace your cracked water heater tank.

We’ll find out what’s causing that whistling noise and fix your water heater in no time. To learn more about what to expect when you hire us, visit our tank water heater repair page for more information.