Water Heater Making Noise? Here’s what to do

water heater making noise

A friend recently asked me, “What should I do if my water heater is making noise?” Aside from calling in a plumber, there are several soundproofing solutions you can try to resolve the problem. I’ll look at these in much more depth later, but here’s a quick answer:

If your water heater is making noise then the first thing you should do is to confirm it’s working properly. Once you’ve done that, the best thing is to soundproof the room in which the water heater is located, as this will make a big difference to the noise pollution.

Along with the best soundproofing solutions for making a water heater quieter, I’m also going to look at the most likely causes of common water heater noises. As mentioned, it’s important to ensure your water heater is functioning correctly before you start soundproofing it.

As an affiliate, I may collect a share of sales or other compensation from the links on this page.

Also read: Boiler Noise Solutions

Why is my water heater making noise?

As with all other electrical appliances, it’s completely normal for your water heater to make some amount of noise. However, even these normal noises can be distracting, so it’s worth trying to block them out if you can.

Similarly, there are quite a few noises that signal a potential issue with your water heater. Before you try soundproofing, check through this list to see if your kind of noise is on it, and try the solution listed to resolve the problem.

1. Crackling, popping or rumbling water heater

Crackling, popping, or rumbling are probably the most common noises a boiler makes, but they’re all indicators of a bigger problem, namely sediment buildup. While sediment buildup is basically unavoidable, it does need removing every now and then.

Sediment comes from a number of sources but is primarily made up of rust from pipes or material already in the water. It’s a particular problem around the water heater’s heating element, and the popping noise is caused by water forcing its way through the blocked pipes.

A rumbling sound is also caused by sediment, but this noise comes from the sediment moving in the actual water tank. Hard water is a big cause of sediment, which is unfortunately unavoidable.

The best solution for this problem is to drain your water heater in order to remove the sediment. Be aware though, this is a pretty long and messy job and could require several flushings to completely remove the sediment.

Along with flushing the tank, you should also consider installing a water softener or electronic water descaler (see this one on Amazon). The descaler is more expensive but doesn’t need replacing as often.

2. Humming water heater

As far as appliances go, a water heater is fairly simple. It consists of a big water tank with a heating element suspended in the middle. The heating element turns on and heats the water, and that’s basically all there is to it.

The water flows around the heating element as it’s drawn in and out of the tank, and this process can cause vibrations. Over time, these vibrations can loosen the heating element, which then vibrates and causes the humming noise.

You can resolve this problem fairly easily by tightening the element, which will prevent it from vibrating. However, while you’re in there, it’s also worth cleaning any sediment off the heating element and replacing the part if necessary.

3. Knocking or hammering water heater

Another very common problem across all appliances with a water flow is a knocking or hammering noise. These noises are usually caused by air trapped in the pipes or through sudden pressure changes caused by the water flow being turned on or off too quickly.

The actual noise is often caused by pipes banging or vibrating because of pressure changes, although it can be heard in the water heater too. While the problem isn’t particularly dangerous for your water heater, it can cause damage to your pipes and walls.

It’s fairly easy to fix this problem, and solutions can involve installing a pressure regulator, fixing loose pipes back to the wall, or fitting a water hammer arrestor (see these ones on Amazon). I’d recommend trying to identify the source of the noise before you try and fix it.

4. Ticking or tapping water heater

Almost all water heaters will make a ticking or a tapping noise, and this is actually completely normal. It’s caused by the pipes contracting or expanding as hot water flows through them.

Alternatively, the noise is caused by the water heater’s heat traps, which is a component that stops water from flowing in the wrong direction. Although there are many different versions of the heat trap, they all function in basically the same way.

If the noise does bother you, it’s possible to install a component called a dielectric nipple, which will make the heat trap much quieter. Luckily these are really easy to install with only minimal DIY knowledge.

Other common water heater noises

On top of the noises described above, you might also experience noises such as sizzling or screaming. These are definitely less pleasant, both to listen to and because of what they indicate.

Sizzling is a sign of either valve issues somewhere on your heating circuit, which needs to be tightened. It could also signify a leak onto the heating assembly, which definitely needs to be fixed as soon as possible.

Many of the issues above are fairly easy to resolve on your own. However, if you’re unsure then call in a plumber to diagnose and solve any problems you’re having with water heater noise.

How to make your water heater quieter

water heater Making Noise

Providing you’re happy that your boiler is just noisy and not acting up, there are definitely things you can try in order to make it quieter. Below is my list of top suggestions for how to do this, and I recommend trying several to get the best results.

However, there are 2 bits of advice I need to give first:

  • Although water heaters will often already be insulated, be careful about applying insulation directly to the appliance. There might be regulations about restricting airflow around the heating components.
  • After soundproofing your water heater, you must be extra vigilant about problematic noises. Make a habit of checking your water heater every couple of weeks for any problems.

Now that’s out of the way, here are my top suggestions for soundproofing your water heater:

1. Insulate the water heater

Many models will already have some kind of insulation fitted to the outside of the tank. However, if yours doesn’t then this should be the first step. As I mentioned above, ensure you’re working in line with any safety guidance about airflow.

The best way to do this is to wrap some fiberglass insulation (Amazon) around the tank. Although this is a product for thermal insulation, it does a good job of muffling sound too.

I’d recommend using vinyl tape for this job because it’s heat resistant. Also, always make sure your water heater is turned off before you start working on it.

2. Soundproof the room

Water heaters are fairly large appliances, and this often dictates where in the house they’re kept. Many older properties might locate them in the attic, although the basement is just as common.

Either way, soundproofing the room in which the water heater is kept will make a big difference to noise pollution levels. However, if it’s kept in a large room then it’s completely understandable for you to not want to soundproof your entire basement.

A solution to this is to build a wooden frame around the water heater, effectively boxing it into its own little room. When doing this, ensure airflow isn’t restricted and that you’re leaving enough space for the soundproofing materials.

I’d recommend using some of the following products to do this:

Rockwool

Rockwool (Amazon link) is an amazing product for soundproofing. It’s mineral wool, which means it’s made from mineral fibers that are spun into fibers and then mashed together. It’s basically identical to fiberglass but is made from mineral.

It works really well as both a thermal and audio insulator, making it ideal for this kind of job. What’s more, it’s fire retardant, which is another massive bonus in a situation like this.

The structure of Rockwool is both dense and open, meaning it traps sound waves and prevents them from escaping. I recommend Rockwool for a number of soundproofing jobs, and soundproofing your water heater is no exception.

Check out Best Insulation Materials for Soundproofing And Acoustics

Mass loaded vinyl

Mass loaded vinyl (Amazon link) is another favorite of mine when it comes to soundproofing. It’s what’s known as limp mass, which means it doesn’t vibrate when it comes into contact with sound waves.

The biggest plus point for this kind of job is that it’s thin, meaning you don’t need as much space around the water heater. Mass loaded vinyl will be a good choice if you have a tankless water heater in a cupboard because you can simply line the cupboard.

The only real downside of this product is that it doesn’t really have any thermal insulation properties, although this shouldn’t be too much of an issue. If you think it is, then stick with Rockwool.

Sound deadening mat

Another good option is a vehicle sound deadening mat (Amazon link), which is designed for use in a vehicle cabin to reduce engine noise. However, it’s just as effective at soundproofing a water heater.

This product comes in a fairly large roll and shares many properties with mass loaded vinyl. However, sound deadening mats also have a layer of foil for extra thermal insulation, which can be helpful here.

It’s generally easy to apply because most mats have an adhesive backing, meaning you just need to stick it to the wall. However, because it insulates heat, I’d definitely recommend drilling some air holes in your water heater cupboard to improve circulation.

Also, read about the Best Sound Deadening Mat in the market today.

3. Soundproof ceiling and door

If your water heater is stored in the basement, it makes sense to soundproof the ceiling too so that you can reduce the level of noise pollution experienced in the house.

Similarly, if your water heater is stored in a cupboard, it’s a good idea to soundproof the door along with the walls. For a cupboard, you can simply follow the same method as you use for the walls.

Soundproofing your ceiling won’t be too difficult either, as you can use the same materials as you did for the walls. Alternatively, you could try using some acoustic insulation foam (Amazon), which helps to deaden airborne sound waves.

Many of these products are fire retardant, but you should always be careful to leave space for airflow, along with not restricting the water heater’s chimney. Although this will mean some noise will escape, it’s better than the alternative.

Check out my guides for

4. Regularly maintain your water heater

Many of the common noises that come from a water heater are caused by potential issues in the system. Luckily, many of these can be avoided through regular maintenance of the appliance.

It’s recommended that you flush your water heater at least once a year, if not twice. This will be enough to prevent issues caused by sediment buildup and will give you a chance to check your heater’s health.

Similarly, you can check for any loose components or pipes, and doing so regularly will hopefully mean you catch any problem before it becomes too big.

However, if you don’t feel confident doing this, then pay for an annual service package. Although you might still want to soundproof against regular noises, having an engineer in to look at your heater once a year will keep it working for a long time to come.

Some final thoughts

It’s fairly easy to soundproof a water heater using readily available materials. Even with minimal DIY knowledge you can install a soundproof box around your heater, which should solve most problems.

However, always check your water heater is functioning properly before you start your soundproofing project. It makes sense to first confirm the noises aren’t a sign of a bigger issue. Also, always ensure you’re working in line with any safety guidance in the water heater’s manual.