Not every person has the ability to whistle, but every water heater does. Depending on your water heater’s settings and the type you have, it has more or less likely a chance to whistle. The main difference between a person whistling and a water heater is that something is always wrong when a water heater whistles. So in this guide, I’ll go over 8 different reasons why a water heater will whistle along with the fixes for each one.
Is Water Heater Whistling Dangerous?
If your water heater is whistling, it is more than likely something worthy of concern. You will probably be fine in the short term (a couple of hours to a day or two). But the longer you let it whistle, the likelier your chance of harming yourself and your family and damaging your water heater.
To be safe, whenever you hear a water heater whistling or making any odd noise, you should assume that it is dangerous and take care of it as soon as possible. Otherwise, the more prolonged the whistling continues, you may have a progressively more complex situation.
How Do I Know What Is Causing Water Heater Whistling?
Knowing the cause behind your water heater whistling is vital.
A whistling water heater means something is wrong with the water heater. From the water pressure being too high to a loose connection, there are multiple possible reasons why it is whistling. Let’s get into the main reasons below…
Reasons Behind Water Heater Whistling and How to Stop Them
Multiple reasons will cause your water heater to whistle. Before checking any of these, you will want to turn off your water heater and let the water tank cool for safety while working on your water heater. Here are the different reasons why your water heater might be whistling:
Loose Connections
If you have any loose connections for inlets or outlets, then you will have the potential for whistling to occur. To fix this, tighten your drain valve, cold water inlet, and hot water outlet.
To prevent it from whistling again, make it a habit of checking that connections are tight whenever maintenance is being done.
Worn Out Connections
The inlet and outlet can wear out over time, and if worn out, they will need to be replaced. There is a chance that you can tighten it to stop the whistling temporarily. However, if it continues to whistle, it is time to replace the inlet or outlet.
Cracked Tank
A cracked tank can happen over time due to rust or sediment buildup. Since the tank is corroding and made of metal, the repair is impossible and will need to be replaced. The inner tanks need to be a single piece of material with no weak spots to work safely.
Trying to repair it would mean needing different materials, which will cause weak spots in your tank. Replacement is the only option.
TPR Valve
If this is where it is whistling, then there is too much pressure built up in the water heater. Set the water heater temperature to around 120 degrees Fahrenheit. If your water is already set to 120 degrees or less, the valve itself is leaking, or the seal around it has failed.
If the valve is leaking, flush the TPR valve, then close it back up to see if it continues to leak. If it continues, then you will need to replace it. If it is the TPR valve’s seal, that will need to be replaced. This is normal since seals are expendable and can be expected to fail at times.
Water Supply
Your water supply can be the issue for the whistling. If you have too much pressure of water going into the water heater, that can also cause the whistling. If this is the case, you will need a pressure release valve put into the pipe before entering the water heater.
Bad Thermostat
If your thermostat is broken, you will need to replace it immediately, as there is no way of fixing it. You will also need to turn off the water heater to stop the whistling because the thermostat will continue to add more and more heat, and it will not stop.
Sediment Buildup
Hard minerals in your water will collect over time and create buildup in your water heater. Not only will this take up more energy to heat your water, but it will also cause corrosion-sensitive spots since the buildup will likely not be an even layer on your tank.
While this can cause whistling, it is rare. The more common signs of sediment buildup will be popping or knocking noises.
Bad Anode Rod
Another reason for your water heater to be whistling could be due to a lousy anode rod. If there is whistling at that location, you can change the anode rod to a zinc alloy rod and clean any scale you see on the heating element.
By changing the anode rod, you can prevent this whistling from returning in the future.
Frequently Asked Questions
Why is There a Whistling Noise When Running Hot Water?
There is a chance that you have a loose faucet and may need to tighten it. If this does not work, though, then you may end up having a water pressure issue. You can try lowering or moderating the water pressure to stop the whistling.
If lowering the water pressure does not work, check to ensure your water heater is not whistling or leaking. If it leaks, you must check your pipe connections and your TPR valve.
What Temperature is Best to Prevent Water Heater Whistling?
The recommended temperature for your water heater is 120 degrees Fahrenheit. At this temperature, your water heater will rarely – if ever – cause the extra pressure from setting a water heater at 140 degrees.
Water heaters have a mechanism to prevent high pressure from causing damage. If the water heater reaches 150 degrees, it will automatically release pressure.
So with the temperature set at 140, you risk the water heater reaching high on accident, and whistling may occur. As long as it is set to 120 degrees, there shouldn’t be any whistling occurring.
Why Does my Tankless Water Heater Whistle?
This will happen for various reasons, but the most common reason for a whistling noise is likely a defective or improperly set pressure valve. If this is the case, you may need to contact a plumber because it is challenging to fix yourself.
Why Does My New Water Heater Whistle?
With it being a new water heater, you can rule out most issues for whistling. The main points to look at are to ensure all the connections are correctly tightened, ensure the temperature is set to 120 degrees, and check your water supply to ensure that the water pressure is not too much for the water heater.
Final Thoughts
Water heaters you own throughout your life may never whistle if you take excellent care of them. However, they will always be capable of whistling.
They are not afraid to blow the whistle when something is going wrong, and you will hear the change and know there is something on your water heater that needs to be fixed or looked at. I hope this guide on how to fix a whistling water heater was helpful. If you have any specific questions, please ask them below in the comments section.
