Water Heater Sounds Like Jet Engine – Causes + Fix!

We all know that it’s not normal for a water heater to sound like a jet engine flying overhead. Typical water heater sounds are usually bearable and easy to ignore. 

These deep screeching or deep rumbling sounds are not only distracting, but they’re also signs of underlying problems. 

You will often hear these sounds if the water heater is packed with dirt or other debris. Over time, sediments build up in the water heater and cause it to sound like a jet engine. 

This article will outline how to fix those unpleasant screeching sounds in your home’s hot water heater.

How Should a Hot Water Heater Sound?

Water heaters are not silent machines. Some would describe them as producing a humming sound at around the same sound level as a desktop CPU. You will probably not notice the sound as you walk past it unless you pay attention. 

Gas-powered water heaters may also produce popping sounds due to condensation on the burner. 

The average sound level for water heaters should not exceed 65 decibels. In fact, many water heater manufacturers boast of a 49db noise rating in their units.

Reasons Why Your Hot Water Heater Sounds Like a Jet Engine

Your water heater may screech like a turbojet or emit a deep rumbling sound like a commercial jet. It’s embarrassing having to explain the source of these disturbing sounds to visitors. 

To help you explain better—and fix the problem so you no longer have to explain it away—it’s necessary to know where the sounds originate from in the system. 

Your water heater will produce deep rumbling sounds when there are excess sediments. Sediments from mineral deposits in the water supply will gradually accumulate and react with the heating element in water heaters. 

These reactions create minor explosions, which are responsible for the rumbling sounds. This may occur once in a while or continuously. 

Conversely, your water heater creates a high-pitch screeching sound when there’s a problem with the water pressure. Too much water pressure can result in a water explosion or fire hazard. 

Typically, water heaters come with safety mechanisms, such as a pressure relief safety valve, for regulating water pressure. The valve opens and releases water when there’s pressure build-up within the unit. 

In a regular water heater, you won’t notice the sound of the pressure relief valve being activated. However, if the pressure valve is faulty and not fully opened, you will hear a screeching sound. 

How to Flush Out Sediments in Gas and Electric Hot Water Heater

Feels like you’ve got a banshee hiding in your water heater? Maybe your neighbors or homeowners association have inquired you about the awful sound.

Thankfully, you can easily reduce jet engine noise by flushing out sediments. Follow these steps to flush out deposits in both gas-powered and electric water heaters:

Step 1: Turn off the heat source 

This step is quite different for gas and electric-powered water heaters. To turn off the heat supply in electric units, unplug the water heater from the power source.

For gas-powered heaters, turn down the temperature settings to pilot or vacation. Doing this prevents the heater from switching on during flushing. Furthermore, it prevents it from melting the insides of an empty tank. 

water heater control valve

Step 2: Close the cold water valve to prevent the tank from refilling during flushing. 

Step 3: Connect a garden hose to the drain spigot. 

Ensure to use a garden hose with a similar width as the spigot. Gently screw one end of the garden hose to the drain spigot, and place the other end outside your house, preferably near the street pavement.

Note that the hot water won’t drain until you let air into the unit. This leads us to the next step:

Step 4: Allow air to enter the unit.

There are two options for letting air into the unit. The first option is to open the hot water side of your bathroom or kitchen faucet. Air will travel through the faucet and into the tank, thus allowing the water to drain via the hose. 

Another option is to open the pressure relief valve. The valve allows air to enter the tank.

water heater pressure relief valve

Image Title: Video screenshot from AmplifyDIY. 

Image Alt: Opening the pressure valve to allow air into the water heater during flushing. 

After opening the pressure relief valve, you should hear air filling up the tank. 

Step 5: Use a screwdriver to open the valve on the drain spigot. 

Use a screwdriver or knife to open the drain spigot. Stand back and watch hot water leaving the water via the hose. 

opening drain spigot of water heater

Step 6: Observe the hot water flow. 

Caution/Warning: Take precautions with any hot, scalding water that gushes out of the water hose. Keep children and pets away from the flow of water.

hot water flowing out of water heater

Did you notice any sediments coming out? Confusingly, the water is probably crystal clear. Here’s a simple explanation: The deposits are well-settled at the bottom of the tank and will not flow out until you stir them up with bursts of water in the next step.

Note: The tank should be completely drained of water by now. 

Step 7: Add short bursts of cold water into the tank. 

Open the cold water inlet for about 20 to 30 seconds. The sudden burst of cold water will agitate the sediments enough to flow out of the tank. Repeat the process at least four times. 

Is the method working? It’s time to find out—let the cold water pour into a white bowl or bucket. You should see small black particles in the water. 

Step 8: Keep flushing until no more sediments come out of the tank. 

Step 9: Fill up the tank with cold water and repeat the flushing process. 

Step 10: Refill your tank and close the pressure relief valve to avoid water spills. 

Finally, plug in your electric water heater. If using a gas heater, move the temperature setting from pilot or vacation to the desired temperature. 

Voila! Your water heater should now function without producing any more rumbling sounds. 

How to Reduce Noise in Hot Water Heater

The pressure valve opens and releases water when the tank’s internal pressure is too high. It should automatically close off after discharging water. 

Over time, the valve corrodes and doesn’t create a complete seal, causing those annoying screeching sounds. You need to replace your pressure relief valve to reduce or eliminate this sound. 

Start with these few steps:

  1. Get an adjustable wrench, Teflon tape, garden hose, wire brush, and screwdriver. Also ensure that you get a suitable replacement at the hardware store. Get a pressure valve with the same BTU, PSI ratings, and thread size. 
  2. Unplug the electric water heater from the power outlet. For gas heaters, shut off the gas valve. Furthermore, set the water heater to the pilot or vacation mode. 

Note: Don’t forget to shut off the cold water valve. 

  1. Now you need to drain the hot water in the tanker. Connect a garden hose to the drain spigot. Next, open the hot water side of your bathroom or kitchen faucet to let air into the tank and reduce pressure. 
  2. Use a screwdriver to open the drain valve for a few minutes. This allows the water level to fall below the pressure valve position. 
  3. Is the water level below the valve position? If so, it’s time to remove the pressure valve. Unscrew the drain pipe attached to the valve. Next, use an adjustable wrench to remove the defective valve. 

Wrap a Teflon tape around the thread of the new valve. Then, use an adjustable wrench to screw it into the water heater. 

teflon wrap around thread

Reattach the drain pipe to the valve, and open the cold water valve. Finally, open the gas valve and set it to the desired temperature. 

Conclusion: No More Strange Noises in Hot Water Heater

Now you know why your water heater sounds like a jet engine. So take out your tools and get to work! Don’t hesitate to contact your plumber if you’re uncertain or not ready to perform these fixes yourself.