Why is My Hot Water Heater Making High Pitched Noise?

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You may hear strange noises coming from your water heater. The noises may include pops, bangs, whistles, and even hisses. Some of these noises may be irritating or even terrifying. Before you rush flying back upstairs in terror that your water heater is haunted, be assured that water heater noises are common.

In the long run, your water heater will produce different unusual sounds as parts wear due to exposure to various elements in the water and environment. But what exactly makes a water heater make high pitched noise?

One of the main reasons your water heater is making high-pitched noise is due to sediment buildup when sediments build up on the bottom of the water tank, which causes hot water to be trapped underneath.

1. Sediment Buildup

Sediment buildup is an accumulation of dissolved or suspended materials, such as accumulated rust, hard water minerals, sand, silt, clay, and other particles. These particles often originate from surface runoff or the decomposition of plants and animals.

The water heater is vulnerable to sediment accumulation, whether your water source is a public system or a personal well. Typically, city water is filtered in a treatment facility, but a finer layer of mineral deposits can form in the water mains with time.

Furthermore, water-main supply breaks and leaks in the public piping system might introduce silt into the water delivered to your house and water heater.

Similarly, suppose your property uses a private well for its water supply. Silt can quickly infiltrate your water heater after traveling via the filtration system and the water supply.

When silt builds up, you’ll start to have issues like:

  • Changing water temps range from excessively hot to mild.
  • Increased power bills.
  • Reduced supply of hot water.
  • Rumbling or popping noises while the heater is running.

When sediment accumulation worsens, it can displace water in the tank, clog the drain valve, obstruct the water lines, and possibly trigger an untimely tank failure. Periodically flushing the tank can prevent these issues.

You can engage a plumber to do this job or do it yourself by applying these instructions.

  • Turn off the electric heater’s circuit breaker or set the gas burner on “pilot,”
  • Then, close the cold water input valve on the tank.
  • Wait a few hours for the hot water to cool down.
  • Place a bucket beneath the T&P valve and verify its functioning.
  • Connect a water hose to the unit’s drain valve and position the opposite end in the bath, laundry tub, or floor drain.
  • Open a hot water faucet, open the discharge valve, and let the tank drain.
  • Shut the drain valve, reconnect the cold water supply, and fill the tank halfway.
  • Continue the process of draining and refilling until the flowing water is clear.
  • Open the cold water supply, close the drain valve, and refill the tank. Close the open faucet after the water begins to flow.
  • Reheat the water by restoring electricity or adjusting the gas burner’s settings.

2. Leaky Water Heater

A leaking water heater can produce a sizzling noise. The leaks could be coming from faulty pipes or water heaters.

an image showing to plumbers inspecting domestic water heating system

The most common causes of a leaking water heater include loose gaskets, broken hot and cold water connections, a faulty drain valve, and rust in the tank. Several of these issues may be remedied with a minor tightening or upgrading to restore the water heater’s full performance.

  • The hot and cold water connections do not work correctly. If the source of the leak is the hot water pipe or cold water supply,  you may be able to resolve the issue with a wrench. If the hot water tank lines are constructed of flexi pipes, you can tighten the connections like a garden hose. If your water pipes are made of copper, you will require expert assistance for soldering.
  • Loose gasket. If water is leaking from the exterior of the electric water heater, faulty gaskets may be the cause. To ascertain if this is the problem, you must switch off the electricity to the heater & remove the “hatch covers” from outside the water tank to reach the gaskets. In the process, you may have to strip some insulation. You’ll have a new project on your hands if you do discover leaks around the gaskets. Replacing gaskets involves emptying the hot water tank and removing all electrical parts.
  • Damaged or faulty drain valve. Does water pool at the bottom of your water heater? In this case, it would be reasonable to presume that the tank is leaky. But that’s not always the case. A broken drain valve (located at the bottom of your tank) might form puddles around the water heater. Empty the water tank and remove any deposits from the valve to resolve this issue. If the leak persists, the drain valve will need to be replaced. This is something that should be left to the experts.
  • Faulty or leaking water tank. This is the worst possible outcome. If you detect leakage in the water tank or if silt accumulation and erosion have rendered the tank irreparable, you must purchase a new water heater tank. This serves as a reminder to keep up with water heater maintenance tasks to extend the water heater’s lifespan.

3. High Water Pressure and Temperature

One of the leading causes of premature water heater leakage is high water pressure. Plumbing codes define your home’s water pressure as 80 psi or less, while most experts advocate 50-60 psi.

Very high water pressure in the tank might cause a high-pitched noise even when the heater is unused. As the water in a tank heats up, it expands and takes up more room, increasing the pressure within. It is known as thermal expansion.

Picture a bicycle tube. As air is pushed into an inner tube, the pressure increases, and the tube hardens. Ultimately, the inner tube will contain so much air that the pressure will force it to rupture.

The same may occur with your water heater. If you’ve got a 50-gallon water tank stocked with cold water, it will expand to at least 52 gallons when heated (due to thermal expansion). The additional 2 gallons will raise the pressure inside the tank.

The pressure inside the tank increases as the temperature rises, and the tank might burst if there is nowhere for the water to escape.

Usually, water heaters have safety mechanisms that activate to prevent bursting. Still, if the technology fails, the tank’s pressure might reach levels that could cause severe damage to your property.

Common Water Heater Noises


Rumbling and Banging

Rumbling and banging are two of the most common noises a water heater makes. Normally, these sounds are caused by excessive sediment accumulation.

When sedimentation builds to a certain level in your water heater’s tank, it could react with the heating element, causing the mini-explosions you hear. This is often an easy issue to resolve and can generally be resolved simply by emptying the water heater tank annually.

It’s also likely that your unit suffers from a water hammer, which happens when the water supply is switched off and rapidly floods back into the pipes. A water hammer can make the pipes break. Therefore you must decrease the pressure in the system by adjusting the pressure-reducing valve.

You can also contact a contractor to inspect the water hammer and assist you with draining your hot tank.

Popping Noise

Like banging, popping is typically an indicator of excess sediment in the water heater tank. Notably, you could be hearing the reaction between the alkaline in the water and the heating element.

Alkaline is high in magnesium and calcium, which generates rust, one of the leading reasons for sediment accumulation. In addition to draining your tank, you may need to repair your water heater’s anode rod (the mechanism that prevents sediment and bacterial buildup).

If you live in areas with hard water, adding a water filtration system may also assist in decreasing rust buildup.

Crackling & Hissing

The majority of electric water heaters emit crackling and hissing noises. This is common with electric heaters, so if your heating system periodically emits a crackling sound, it generally does not cause concern.

Yet, if these sounds persist, the system’s heating element may be clogged. This is a more serious problem that may need draining your tank and/or contacting a professional for an assessment.

If your water heater is powered by gas or oil instead of electricity, it’s more probable that the cracking noises are due to moisture buildup. If you hear these sounds from your gas/oil water heater, contact a professional to see if water is gathering around the device.

Even though your water heater is not electrically driven, it still needs electricity for operation, and you do not want water to contaminate its electrical components.

Ticking Sounds

It is somewhat unnerving to hear ticking noises from the water heater like it’s about to explode. Thankfully, the situation is likely not as severe as described.

If you hear a ticking sound emanating from the water heater, the cause is likely an abrupt water pressure shift. If this noise persists, locate the pressure-reducing valve and adjust the water heater’s pressure level.

Moreover, you may add additional straps and/or insulation around the water heater to stop it from shifting and being influenced by fluctuations in water pressure. If this ticking sound persists, contact a specialist.


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