Is a Noisy Water Heater Dangerous? Sounds to Look Out For.

Got a water heater emergency? We’re on call 24/7! Don’t hesitate to reach out.

A functioning water heater is one of your home’s most valuable assets. After all, no one enjoys stepping into the shower, washing the bedsheets or doing the dishes only to discover there’s no hot water. So, if your unit starts making strange noises, it’s natural to wonder if something’s wrong.

When it comes to unusual sounds from your water heater, it’s best to use caution. Failing to take care of issues could lead to costly property damage, injuries and a lot of inconvenience. Take a closer look at water heater noises and the causes behind them.

Do Water Heaters Normally Make Noise?

Most water heaters (both tanked and tankless) make some sounds that are nothing to worry about. You might observe: 

• Subtle crackling when condensation makes contact with a gas-powered heater’s burner.
• Light clanking as metal components expand or contract with heat.
• Ticking, which is often caused by normal changes in water pressure.
• Humming from the unit’s components or from cold water entering the tank.

Sometimes, however, even small noises may signal large problems with your water heater. If you begin to notice unusual sounds you haven’t heard before, it’s something to look into.

Bad Water Heater Sounds Explained

Abnormal sounds from your water heater may indicate various issues and merit further investigation.

1. Popping or Cracking

Cracking and popping are among the most common signs of a water heater problem. These sounds usually indicate sediment or mineral buildup inside your tank. Such deposits can trap water, reduce efficiency, cause uneven heating and increase water pressure. The added water pressure is particularly concerning, and some systems may burst or explode in these conditions.

2. Banging or Knocking

An occasional knocking from your water heater may not be unusual. Some heaters experience a “water hammer” effect when the system shuts off. This is caused by the sudden change in water flow, which causes shock waves in the pipes.

On the other hand, knocking might signal problems. A new knocking sound when the water cuts off might be a sign of loose or damaged pipes, or a damaged heat trap (which keeps hot water from flowing backward). Knocking might also come from the movement of sediment or minerals in the tank.

3. Hissing or Sizzling

Hissing or sizzling in your tank may occur if condensation forms on the unit and then drips onto hot elements (like the burner). However, these sounds may also signal problems like: 

• Water leaks. If you notice a drop in hot water volume, lower hot water pressure or the telltale puddle on the floor, it’s a good sign that there is a leak. 
• Increases in water pressure or temperature. Many water heaters contain automatic valves to help balance the temperature and pressure of the water within. If a problem overwhelms the valves, hissing may result.
• Gas leaks (if you have a gas-powered water heater). The escaping gas could spread throughout your home and put you and your loved ones at risk of explosion, fire and toxic exposure.

4. Humming or Buzzing

As previously mentioned, humming and buzzing are sometimes simply the result of water entering the water heater tank. These noises may also come from components of the system as they work. However, unfamiliar humming, buzzing or vibrations may indicate loose parts. These items will need to be tightened or replaced to prevent worsening issues.

5. Screeching

Screeching or whistling may come from a couple of sources. The issue often arises if your inlet control valve—which controls the water flow into your tank—is clogged or partially closed. You may simply need to adjust the valve to fix the issue. Still, if the problem persists, contact a professional.

6. Beeping or Alarm Sounds

Some modern water heaters include bells or beeps that sound when the system is actively heating water. Many also include safety panels and alarms that sound in case of a maintenance need or a more serious issue (e.g., overheating or pressure issues). If you hear such an alarm, call a professional.

Why Ignoring Noises Can Be Dangerous

One thing you should never do is ignore water heater noises, especially when these are noises that you aren’t supposed to hear regularly. Beyond signaling existing system damage, strange sounds may also indicate problems that put you and your property at risk.

• Water damage from a leaking tank can threaten your home’s structural integrity and cause mold.
• Sediment deposits in the tank could raise water pressure, increasing the risk of ruptures or explosions.
• Gas leaks run the risk of fires or explosions. 

Moreover, you face considerable personal injury risks from a problematic water heater. Sediment within the tank may contain unhealthy toxins or bacteria. There’s also an increased risk of scalding or burns if your water is too hot. Gas leaks can also pose risks of carbon monoxide poisoning.

Take any strange sounds from your water heater as a call to action. Immediately contact a professional plumber and describe the issue. If it’s safe to do so, turn off the heater and its water supply by following the instructions in the owner’s manual. Wear insulated gloves to avoid accidental burns. Do not turn the system back on unless your plumber gives you permission. 

Preventing Water Heater Problems

The best way to avoid noisy problems with your water heater is to keep your system in good working order. Regular water heater maintenance can help your system continue to function optimally, reduce water waste and prevent small problems from becoming big issues. At a minimum, you should have your system flushed annually to reduce the risk of sediment and mineral buildup, which are often at the root of many unusual sounds. Your plumber may also recommend other spot maintenance at this time.

For Water Heater Problems, Call a Professional Plumber

Whether you’re noticing unusual sounds with your water heater or simply want to keep your system in good working order, it’s essential to have a trustworthy plumbing service by your side. That’s where CK’s Plumbing & Backflow comes in. We’re Raleigh’s and the Triangle’s most trusted expert plumbers, and whenever your water heater’s making you heat up, we’ll be there to get things back under control. Give us a call at (919) 426-2467 or request your free service estimate today.