Strange noises from your water heater can cause concern, but you don't have to panic! This is actually a common problem that homeowners face. There are a few different things that could be causing the noise, but the good news is that most of them are relatively easy to fix.

Here’s what could be causing the noise and what you can do about it.

Causes of Water Heater Noises

Here are the typical water heater noises and what they indicate:


There are several potential causes of humming sounds in a hot water system. One is simply the normal flow of water through the pipes. When water is heated, it expands, and this can cause the lines to vibrate, creating a humming noise. Another potential cause is a build-up of residue in the pipes.

Knocking or Hammering

When you hear a knocking or hammering sound from your hot water system, it usually indicates a build-up of sediment in the bottom of your water heater.

Over time, deposits accumulate in the tank. When the water is heated, these sediments can become complex and form a crust on the bottom of the tank. When this happens, the heat from the burner causes the crust to break loose and create the knocking or hammering sound you hear. Also, when the water in the tank is heated, the elements expand and contract, causing the metal to make a knocking or hammering sound.

You must ask a professional for plumbing advice if you hear a knocking or hammering sound from your hot water system. This sound can indicate a serious problem and, if not addressed, can further damage your hot water system.

Gurgling, Cracking or Popping Noises

One of the most common causes of gurgling sounds in hot water systems is air in the pipes. When there's air in the lines, it can cause water to bubble and make all sorts of strange noises. Luckily, this is usually an easy fix. All you need to do is open a faucet and let the air escape. Once the air is out, the gurgling should stop.

Sediment build-up is another common cause of these sounds. Over time, minerals in the water can settle at the bottom of the tank and create a barrier between the heating element and the water, causing water to bubble and make strange noises.

Screeching or Screaming Noises

The high-pitched screeching and screaming noises from your hot water system could be due to too much pressure in your hot water tank. This might indicate a faulty pressure valve. You should get a professional plumber to check the water tank before the pressure build-up causes cracks, leaks, or tank explosion.

If the noise is more subtle, it could be caused by scale accumulation.

Kicking or Tapping Noises

The most common problem is a loose connection between the hot water heater and the cold supply line. Tightening the connection can fix the kicking or tapping noises. Another common cause of kicking or tapping noises is debris in the pipes.

If the noise continues, it could indicate deposit build-up in your water system. A faulty temperature sensor or leaky valve can cause kicking or tapping noises. A plumber can diagnose and fix the problem.

Bubbling Noises

When your water heater tank has a heavy layer of sediment on the tank's floor, heat is trapped under it. When your water is heated, this heat causes the debris to escape causing the bubbling sound. Draining the mineral build-up from your water tank should fix the noise.


The best way to prevent deposit accumulation is to have your hot water system flushed often. This will remove all the sediment and minerals that have built up over time, and it will also help to extend the life of your water heater.