Why is my hot water heater making a sound?

Most people don’t realize their water heater is one of the most used appliances in their home. Steadily dealing with heavy workloads, it’s no wonder the water heater is also in constant need of repairs. From water heater installation to end of life, they do so much for us, so when the water heater is making noises, this is often a signal of sediment collecting in the bottom. However, other reasons can also make the water heater make knowing, screeching and tapping sounds.

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Common Water Heater Noises

Although noise is relatively normal for most water heaters, it’s a sign that something is reducing the volume at the bottom of the water heater’s tank and needs to be addressed before it turns into something major, like leaks.

1. Humming

Humming noises coming from the water heater can be an indication that some components are coming loose. These sounds happen by the vibrations occurring within the water unit itself. Luckily, there’s an easy solution that anyone can do to solve this noise.

The solution: Ensure the water heater is off so that you can inspect that all elements are tight. Before you start tightening screws, bolts and other pieces, make sure the water heater has been turned off for a few hours. Otherwise, the water inside could be scorching and if any leaks happen, you could quickly get burned.

2. Knocking or Hammering

A hammering sound is a strange one to hear coming out of the water heater. This is often caused by water crashing into shutoff valves too quickly. This isn’t a concerning issue, but it can be pretty loud and annoying. Sediment buildup can also cause these knocking or hammering sounds, as steam bubbles can’t reach the surface. The sediment moving up and down the water tank will also cause these noises.

The solution: In this case, an extra piece can help stop the noise. You can find a water hammer arrestor at a local hardware store to absorb the shock when water stops due to fast closing shutoff valves. A water hammer arrestor is relatively easy to install and will take care of the sound instantly.

3. Screeching

By far one of the scariest noises a water heater can make. We associate screaming or screeching sounds with pressure issues. In this case, it’s probably the valves in the water lines causing the problem. When these valves cannot be fully open, water is forced to squeeze through them, building pressure that causes the well-known high-pitched noise.

The solution: You’ll likely need the help of a professional plumber to fix this noise. They can help inspect the valves to ensure they can open and close perfectly.

4. Tapping

Similar to screening noises, tapping sounds are an indicator that your valves need adjustment or replacement. In some cases, tapping noises can also mean you have sediment buildup in your water tank. Both issues might require a professional plumber to help fix the problem.

The solution: A professional plumber can check the valves, inspect all of the water heater’s elements and drain the water tank to remove sediment buildup. These steps should take care of the noise.

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How to Prevent Sediment Buildup

Fluctuations in water, loose pipe straps and water leaks can also cause irritating water heater sounds. But, in most cases, sediment buildup is the primary precursor of water heater noises. Some ways to stop sediment buildup and maintain your water heater in perfect shape include:

• Slow sediment buildup: every three to four months, take a bucket of water out of the tank. At the bottom of the water heater’s tank, you’ll find the drain valve – use it to drain the water tank. Try to do this after the water heater has been unused to prevent scorching hot water from coming through. Doing this every trimester can help prevent sediment buildup in the first place, but it can also cause leaks, so keep checking to see when the valve will need replacement.
• Flush the water heater: at least once or twice a year, flush out your water heater. To flush all sediment out of the tank, you have to empty it. Open the cold water intake and fill the tank halfway. This will help rinse out the sediment. Continue draining the water and repeat until you don’t see any more traces of residue left in the tank.
• Use water softeners: you could also add a water softener in your water tank to eliminate sediment buildup in the first place. A water softener is a filtration system that keeps calcium, magnesium and other minerals from accumulating and causing hard water.
  When left unchecked, levels of sediment buildup can cause a bigger problem. For example, the bottom of the tank can turn rusty and leak, which is why you might hear some sounds in the first place. At this point, the only option to fix the problem is to replace the water heater.

How to Change Your Water Heater

Once the water heater starts rusting, it’s just a matter of time before a leak occurs. Here’s how to replace the water heater:

1. Shut off the water heater entirely. Make sure water, electricity and gas power have been turned off.
2. Open the valve at the bottom of the tank to drain all the water out. Some water heaters allow a hose to be attached to the drain to make the process easier.
3. Ensure the tank is empty before you start disassembling it. Disconnect all the water lines, power wires and pipes from the water heater.
4. At this point, you can remove the old water heater and clean the area to make space for the new one.
5. Place the new water heater in place. Go ahead and reconnect all water lines and pipes. Ensure everything is set in place and well adjusted. Remember, loose valves can cause noises too.
6. Turn on the gas or electric power and begin to fill the water tank. Wait until the thermostat reaches the desired temperature, which for most water heaters is 120 degrees Fahrenheit.​

A water heater making noises is usually harmless. But, too much sediment can eventually cause damage to the inner lining of the water tank, leading to a leak. When this happens, replacing the water heater is likely to be the only viable solution. At this point, hiring a professional would be best.

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Are you curious as to why your water heater might be making noise? Should you perform maintenance, call a plumber, or just ignore the sounds? Worried that it might be on its last leg? We all know water heaters can be expensive to replace so it’s good to know what sounds might be serious and which ones might not be.

Water heater noises are pretty common, and they are usually an indication that you will have to at least do something about it. The list below are the most commonly reported water heater noises, as well as solutions that you as a home owner might be able to implement. We hope this helps you determine what steps you need to take to keep your water heater running at its best.

Your Water Heater might be Making Rumbling, Crackling, or Popping Noise

Water heaters heat the water in the tank. But did you know as the water heats, bits of sediment are boiled out of the water, and these bits of sediment collect on the element tubes and anode of your water heater. Layers of sediment build up inside your tank, trapping water underneath the layers of sediment. As the water heats up, it bubbles up through the sediment deposits, sometimes breaking off the sediment and causing it to become loose in the tank. This popping or crackling sound you are hearing is the action of hot water forcing its way through the layers of sediment that has accumulated. There are some home owners who report hearing a rumbling sound and wonder what it is. The rumbling sound comes from broken off chunks of sediment swirling around inside the tank.

Flushing A Water Heater

What Can You Do To Help Fix This?

If you hear your water heater is making crackling, popping or rumbling sounds, then it’s a problem with built up sediments in the tank. To fix this, if your water heater is under ten years old, you can get away with using a deliming mixture to flush the sediment out of the tank and then flush and drain your water heater.

We recommend flushing and drain your water heater once a year to prevent this problem. Too much sediment reduces the efficiency of your water heater and can reduce the life of your water heater. A properly maintained tank water heater can work well for 15 years, but an unmaintained water heater will usually have catastrophic failure in about 10 years.

When you do flush the tank if it’s still making noises, you may want to check the thermostat. If your thermostat is set at 125 degrees or higher, the noises may be created by the expansion and contraction of the tank from the heat. Reduce your thermostat setting to 120 degrees or lower (this is recommended to prevent accidental scalding) and then listen to see if the noise continues.

Please note that if your water heater is over ten years old, you may actually cause problems within the tank if you try to delime and flush. It’s probably best to start researching what type of water heater you want next and to prepare to replace the water heater soon. South End Plumbing can help you in selecting the right type of water heater for you if you’re ready for a replacement.

Is Your Water Heater Humming?

Now if your hearing a humming noises, this most likely means that your water heater element is loose, causing the water flowing around the element to cause vibration that sounds like humming. This type of noise is of no concern. When the humming noise bothers you and you want to correct it, you can have a plumber tighten the element. Tightening the element is also something the home owner can do themselves if they are handy.

What If Your Water Heater Is Making A Hammering Noise?

May plumbers call this “water hammering”. This is literally a knocking of the pipes as they are mounting hitting the wall. This can happen because the pipes are not securely anchored and they are slapping the studs or the interior of the wall because of water pressure. It can be caused by abrupt turning on and off of water also, such as a toilet being flushed or water pump that does not have a holding tank to distribute the flow of water at a slower rate. Thankfully this is not an urgent issue, but it is possible that you might end up with some damage after time if not fixed. This problem does nothing to your water heater in any way, so don’t worry about replacing water heater because of it- that’s not the source of the noise or the cause of the knocking. To fix this you can have a plumber install a water hammer arrestor which should take care of the issue.

What If You Hear A Hissing Noise At Your Water Filter?

Hearing a hissing sound usually indicate a leak. You’ll want to look for water or steam coming from the water heater or a pipe leading to it. A leak of this nature most of the time requires repair by a professional plumber. In cases where the water heater is old, it may be better to do a water heater replacement. Make sure you aren’t incurring water damage somewhere, and then call South End Plumbing to service your water heater.

Do You Hear Your Water Heater Making A Screeching Sound?

Those high pitched sounds are water being forced through a small opening under great pressure. This is usually caused by a valve that’s not opened all the way.  The valve in question may be at your water heater or it might be closer to faucets in your home or near an appliance. Listen carefully to hear where the noise is coming from to determine the location of the valve. To fix this you might need a new valve at the water heater itself, make sure this is something your familiar with or have a professional plumber do this because there’s high risk of injury due to steam burns. If the loudness of the noise is closer to a faucet or appliance, you may be able to replace the valve yourself if you’re handy. To proceed just make sure to turn off the water to that sink or appliance, then adjust or change out the valve.

Is Your Water Heater Making A Ticking Sound?

When your water heater is making a tapping or ticking sound that usually comes from heat traps or check valves that have been installed to encourage water to flow in the correct direction. This type of noise might also come from water heating and cooling in the pipes.  Some home owners are picky and the ticking or tapping noise them, in that case you can replace the heat trap with a dielectric nipple. There are some cases where this does not guarantee the noises will stop. Knowing this though, just realize that this is not indicative of any real problem, if you only occasionally hear it when you’re in the room where your water heater is located it’s going to make the most sense to try to ignore it.  As they often say, “if it ain’t broke, don’t try to fix it!”.