Why Is My RV Hot Water Heater Making Noise?

You probably have a hot water heater in your RV to shower and for other such purposes. However, sometimes those hot water heaters can make various noises like humming, whining, squealing, or buzzing. So, why is my RV hot water heater making noise? and is this something to be concerned about?

Common reasons for an RV hot water heater making noise include mineral and sediment buildup, restricted water flow, leaks and condensation, high Ph water levels, water pressure fluctuations, and problems with the heating element.

We have put together a helpful guide covering the 7 common reasons for the noises, and what you need to do to fix the issue.

RV water heater making noise

7 Reasons Why Your RV Hot Water Heater Is Making Noises

We want to take a look at all the reasons why your hot water heater is making noises. One thing to keep in mind here is that one way to pinpoint the problem is by paying attention to the specific noise. 

Hot water heaters can sizzle, drip, bang, rumble, squeal, hum, buzz, and more. So, always pay close attention to the noise that your hot water heater is making, as this will help you determine what the cause is.

1. Mineral And Sediment Deposits Have Accumulated

If there is lots of sediment or mineral buildup in your washer feature, there are a lot of noises that you may hear. Sediment can be sand, minerals, or debris that come in through the waterline.

First of all, if there is a mineral deposit in the water heater, some of the minerals can coat the inside of the tank, which is called limescale, and this can result in a popping sound.

If the water heater is not flushed on a regular basis, sediment can accumulate at the bottom of the tank. Then, when the water heater heats water, steam bubbles develop under that sediment and pop.

This is the popping sound that you hear. You may be able to flush the tank out, although if the sediment buildup is too severe, getting a new tank may be required.

If you hear a rumbling noise, it could be that water is making its way through the sediment. If this is the case, the sediment buildup is probably extremely severe, which means that you either need to flush it, or even get a new one.

If you have an electric water heater and you hear some kind of popping, hissing, sizzling, or cracking noise, it could be that the lower heating element is buried under sediment buildup.

If this is the case, you need to drain the tank and clean the heating element. If this is not possible, you may need to purchase a new heating element.

2. The Waterflow Is Restricted

Restricted water flow can also cause a number of sounds to occur, such as a sizzling noise. If you hear a sizzling noise, it may be an indication that there is a problem with the valve. You, therefore, want to check the relief valve to see if the sound is coming from it. 

If it is, you will most likely need a professional plumber for help. You then want to see if the sizzling noise is coming from the inlet valve, and then make sure that it is fully open. 

You then want to check all other valves and lines to make sure that there are no kinks and that everything is fully opened. if this does not appear to be the issue, move on to the next problem.

3. Fluctuations In Water Pressure

It may also be the case that there are water pressure fluctuations inside of the plumbing, which will often cause a ticking noise to happen. Water heaters often outlet and inlet nipples with heat traps, which are designed to allow for better energy efficiency. 

These nipples are going to be found on top of the water heater where both the inlets and the outlets connect to the heater. Put your ear beside it to see if this is the source of the ticking noise. A good solution here is to replace those old nipples with new nonheat trap nipples.

It could also be the case that due to fluctuations in warm and hot water, this can also cause pressure fluctuations. if the pipes are cold, and hot water flows through them, they will expand, and vice versa. The pipes can then rub against the frame and the interior components of your RV. 

If this is the case, securing the pipes to the wall where the sound is the loudest is the best solution. You can always turn back the temperature in the water heater by a couple of degrees as well, as this will help reduce pressure inside of the pipes.

4. Condensation And Leaks

If you hear the hot water heater making a noise such as running water, then a broken pipe or a leak is the most likely cause.

Now, when water is being drawn into the tank, it is normal to hear running water, but if the noise continues when the tank is full, you will need to investigate the situation or call a professional plumber. 

One way to check this is by feeling the hot water pipe. If the hot water is not being used at the moment, the pipe should be relatively cool.

You then want to put your ear next to the hot water outlet pipe to see if you can hear anything. If there are no taps on, but you can hear water running, then there is a leak. 

You then also want to make sure that your T&P valve is closed. If you close it and it doesn’t stop the water flow, you will probably need to replace it. If all else fails, you might just have broken plumbing, in which case you will need to call a professional for help.

If your hot water heater happens to be gas-powered and you hear a sizzling noise when the burner is on, then condensation is likely the problem. Condensation can form and then drip onto the components of the burner, and if the burner is hot, you’ll hear a sizzling noise.

The other reason for your hearing is sizzling noise is if there is a leak inside the hot water heater. This is something that will usually happen when the burner is off. If you find a puddle or some water nearby, this is the cause, and you will need professional assistance.

5. The Water Source Itself

If you hear a popping noise, and you have an anode rod that is made out of aluminum, and your water has a high pH level, or in other words, it’s fairly basic, an aluminum hydroxide reaction could occur. This is a very common occurrence especially if your water has a lot of chlorine or chloramines in it. 

When this aluminum hydroxide reaction happens, a substance somewhat like a gel will form at the bottom of the tank or on the anode rod.

If this is the cause, you will need to flush your water heater tank and delime it. You will then also have to replace that aluminum anode rod with a magnesium anode rod.

6. The Water Hammer

The water hammer may be to blame for a hammering or knocking sound. When you have the water turned on, but then turn it off, there is no place for the additional water to go within that plumbing, so it then flows back to its original source, which is the water heater.

This can then cause a hammering or a knocking sound, which is caused by the water being shut off abruptly. This can actually be a huge issue, as it can cause the tank of the water heater to expand. It can even deform the top of the tank or burst a pipe.

If this is the cause, you will want to install a so-called water hammer arrester that will help protect your devices and stop that shockwave from occurring when the water is abruptly shut off.

7. The Heating Element 

If you hear a humming noise coming from your hot water heater, it could be the heating element that is the problem. Generally, your hot water heater is going to have an upper and a lower heating element. 

When cold water flows into the tank and circulates around the system, it could cause the upper heating element to vibrate and make a humming noise. 

Although this can be a bit annoying to listen to, it’s quite normal, and all you really have to do is to use an element wrench to tighten that element.

How To Get Air Out Of RV Hot Water Heater

Purging the air out of your RV hot water system is quite easy. All you have to do is open the faucet that is the furthest away from the heater. If it is spitting and not flowing constantly, leave it on until a steady stream comes out. 

You then want to work your way back from the furthest faucet to the closest faucet in corresponding order. Turn on each of the faucets until a steady stream comes out. Make sure that the water pump is on while you do this.

How To Test RV Hot Water Heater Element

If you think that the heating element in your hot water heater is not working, there is a simple way to test for this. Follow the steps as indicated below to test your RV hot water heater element.

  1. Make sure to shut off the power to the hot water heater. Generally speaking, this is going to be done by turning off the circuit breaker or by removing the fuse, if you have an older RV. 
  2. You are now going to see two metal plate covers on the side of the water heater which covers the heater element and the thermostat. Unscrew these plate covers.
  3. You’re now going to see a thin plastic shield between the metal cover and the feature element, as well as a layer of insulation. You should be able to remove all of these components by hand. There should also be small metal tabs that clip the plastic shield onto the water heater.
  4. With everything removed, you’re now going through wants to locate the heating element and thermostat, which should be clearly visible with those covers removed. The heating element itself, the visible part of it, is going to have a 1-inch square base that features two screws with wires running to them. These two screws are what you are going to be testing.
  5. Use a non-contact multimeter to make sure that the power is turned off.
  6. You are now going to turn the multimeter to the lowest setting in regard to the ohms. Ohms will tell you how much resistance the circuit of the heating element has. You are going to touch the red probe of the multimeter to the center of one of the screws of the heating elements, and the black probe to the other screw. It doesn’t matter which screw you touch to which probe. the multimeter should read anywhere between 10 and 30 ohms if it is working properly. If it is reading below 10 ohms, it’s not working properly and will need to be replaced.


We hope you have found our guide helpful and you have been able to fix your Noisy RV water heater. If you feel like you have tried everything or feel it’s outside of your expertise then we would recommend calling in a professional.

Madeline Cooper