Why Is My Water Heater Making Noise?

Water heaters make a moderate amount of noise when they operate - that’s normal.

When the sounds become louder and distressful, you should look into the issue before the problem escalates into an expensive water heater repair or water heater replacement.

Let's talk more about water heater noises and what you can do about them.

Water Heater Noises and Their Meanings

There are a couple of different noises that may be coming from your water heater. Identifying the noise can help you diagnosis the problem. Of course, we recommend getting a proper diagnosis from a professional.

Even if there isn’t a problem with your hot water heater's functions yet, funny noises indicate that you should be on alert - a problem is sure to pop up.

Screeching/Whistling/Hissing

Water heaters often hiss when the water temperature gets too high and must escape from the pressure relieve valve. To resolve the issue, lower the temperature.

The hissing sound sometimes indicates a faulty check valve. In this situation, tighten the valves yourself. If the valve is as tight as it can be, you may need to replace the valve. Luckily, this is a relatively simple repair, and the rest of your water heater shouldn’t be impacted if you resolve the issue quickly.

If you have a gas water heater, the sound could be water getting into the gas burner or a gas leak. Turn off the gas to your water heater and have a professional diagnose and repair the problem.

Do not continue to use your water heater if you smell gas!

Humming/Vibrating

Humming noises often occur in electric water heaters. The humming noise in an electric water heater develops as water runs through a loose heating element, causing the heating element to shake gently inside the unit. The humming noise should stop when the hot  water heater is not in use. 

The heating element is the item inside of the water heater that generates heat and heats the water. It’s attached to the inside of the tank, but it can become loose after wear and tear. There are generally two heating elements in an electric water heater: an upper element and lower element. 

A technician can come to your home to tighten the heating element for you. If there’s noticeable damage, the tech may replace the heating element.

Clanking/Banging/Popping

Clanking and banging noises emitting from your water heater generally indicate sediment buildup. Sometimes, people describe the sounds as a popping noise. A popping noise indicates the same thing. 

All water contains minerals, such as calcium and magnesium. As water heats, it evaporates, leaving those minerals behind. The minerals accumulate inside of the unit. The sound you hear are the calcium deposits at the bottom of the tank getting heated and exploding. 

You should be able to remove the sounds by flushing the water heater. Flushing the water heater involves running water through it repeatedly at full force, forcing the sediment buildup out. Fill the tank and empty it over and over again until you no longer see mineral deposits flow out with the water. Tankless water heaters require a subversive water pump to flush it out. You should flush  your water heater at least once a year - more if you have hard water. 

These sounds can sometimes indicate a water hammer, which is when water flows the wrong way through a pipe. Since water hammers can cause serious damage to your plumbing, it’s important to install a water hammer arrester or check valve as soon as possible to prevent the problem in the future.

Shaking Water Heater

If your water heater is literally shaking, that may mean that the pressure inside the unit has reached unsafe levels. Heating water creates pressure. If you have your water heater set at temperatures higher than recommended for standard residential use or sediment buildup impact the temperature sensor, the pressure can buildup. There’s a pressure relief valve designed to release excess pressure. If the pressure relief valve breaks, the pressure will not have anywhere to go. While rare, the water heater can eventually explode if not treated. 

In the case of a shaking water heater, turn the unit off immediately. Flush the water heater, ensure you have a working pressure relief valve, and keep temperatures at 120°F or lower.

U.S. Water Heating Solutions

Whatever noise your water heater is making, U.S. Water Heating Solutions has a resolution for you! 

Factory-trained techs will come to your home to diagnose and resolve the problem. We even have the most popular parts on hand when we arrive. After you resolve the issue, be sure to sign up for preventative maintenance to ensure that the problem doesn’t come back. 

Remember to talk to the manufacturer first if your water heater still falls under warranty. Then, contact U.S. Water Heating Solutions to schedule an appointment for your repair.