Almost all appliances make some kind of noise, but when you hear something out of the ordinary, it can be concerning. The water heater is one of the most frequently used pieces of equipment in the home so when something doesn’t sound right, it is important to rule out issues that may result in repairs or replacement of parts.

What's that sound?

There are various sounds a hot water heater can make, and many are not cause for alarm.

Here are the most common noises water heaters make:

Banging:

If you hear what sounds like a “water hammer,” it is usually caused by the plumbing system when water is forced to stop or abruptly change direction. This results in a pressure surge and can potentially burst pipes in your home and lead to damage to your water tank. It is important to contact a plumber to deal with this situation. They may install a pressure-reducing valve or a water hammer arrestor but they will need to evaluate the situation before determining the best course of action.

Sizzling:

If you have an electric water heater: sizzling, crackling and hissing sounds are most likely caused by sediment build-up in the base of the tank. This can be fixed by flushing and draining the water heater. Sediment build-up can also cause increased energy bills since the system has to work harder to heat the same amount of water. If you have a gas-powered water heater making these sounds, it is usually caused by internal condensation that sizzles when it drips onto the burners. This could be a sign of a leak in the tank. It is important for a professional plumber to inspect this issue.

Rumbling:

Rumbling is usually caused by a build-up of sediment (a common issue with hot water tanks). This issue is especially common in areas with hard water. The rumbling noise occurs when the hot water pushes through the mineral deposits that have settled at the bottom of the tank and causes the sediment to shift against the sides and bottom. This sediment can be removed by flushing and draining the water heater. A descaling solution can also help breakdown limescale found inside the tank. It is best to have a professional handle these services.

Gurgling:

Mineral, rust or sediment buildup are usually the culprits that cause hot water heaters to make gurgling noises. Older water heaters are more prone to rust and mineral buildup. To learn more about whether or not you may need a new water heater, read our blog here.

Popping:

When sediment and limescale builds up in your water tank, steam bubbles can form and burst underneath, causing a popping sound. Using descaling products can help. Having a plumber flush and drain your hot water tank once a year is the most effective solution to avoid sediment buildup. 

Humming:

Vibrations within the unit can cause components to loosen and often results in humming noises. This is a simple fix and can often be avoided with a yearly maintenance appointment.

Screeching:

Screeching or screaming noises occur when check valves cannot fully open and the water is forced to squeeze through. This builds pressure and causes the high-pitched noise. We recommend you call a professional plumber to deal with this issue.

Ticking:

Many water heaters have check valves, or heat traps in the pipes on top of the heater. They prevent water from flowing in the wrong direction in the pipes that can make ticking or tapping sounds. These are normal noises but if they are bothersome to you, the heat traps can be replaced with dielectric nipples, which are smaller fitting and perform the same function.

If you have any questions or concerns, feel free to contact us and we are happy to inspect your system to make sure it is working efficiently and effectively.

Whether you need 24-7 emergency service or a solution to improve your indoor comfort—at home and work—call us at 781-224-2400 or submit a convenient contact form.

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