Why Does My Expansion Tank Make Noise And What Does It Mean?

When water heats up, it creates extra pressure. This will lead to the thermal expansion of water. An expansion tank is a valuable item that decreases stress on ball seals, safety valves, and valve stems.

However, smooth functioning is vital to performing consistently.

Many homeowners sometimes wonder themselves why on earth their expansion tanks make noise! Well, it can happen for different reasons, such as condensation buildup, excessive water pressure, non-return valve failure, condensation buildup, etc.

Let’s check it out in detail!

Reasons Behind An Expansion Tank Makes Noise

Are you wondering why your expansion vessel has been making a gurgling sound for a long time? Below are some common causes you can check out if your expansion tank is making noise.

  • Excessive Water Pressure
noisy expansion tank

Do you know the ideal pressure your expansion tank should maintain? Generally, it should be no more than 80 PSI.

If your water supply line has more than 80 PSI water pressure, the expansion tank may struggle to retain the ideal level of water pressure.

This may often cause the expansion tank gurgling.

  • Over Charged Expansion Tank

An excessive amount of air charge may lead to system overpressure. You will notice some water is coming out from the relief valve due to intense pressure.

Hence, it is mandatory to double your external expansion tank whether it has the ideal level of air pressure. Maintaining a perfect level of water and air pressure is vital.

  • Non-return valve failure

Do you hear a water hammer after installing the expansion tank?

Sometimes, incorrect installation of non-return or check valves can cause this problem.

Proper assembling of each part of the valve is important too. In addition, choosing an incompatible valve can cause different types of issues. You may notice premature failure too.

Another common reason for non-return valve failure is insufficient maintenance. Ensure the pipelines and valves don’t have a heavy accumulation of debris. Otherwise, they will clog.

If your water supply line is flowing water reversely, it can cause heavy damage to the check valve within a short time. So, make it is working properly. Or change it if necessary.

  • Condensation Buildup

When your expansion tank has an excessive amount of water storage, you may notice condensation buildup in the outside areas.

Another common reason could be excessive heat in the water system. Extremely hot water will cause condensation buildup if the room where you have set up doesn’t have much space.

If you can’t handle a problem of your own, call a professional. Don’t delay. Otherwise, it will rust. Also, you may see dripping water issues.

  • Air Blockage
expansion tank

Air is vital inside the hot water system of your expansion tank.

If the air gets trapped inside your expansion vessel may have hydronic airlock issues.

This air blockage can lead to unwanted sounds.

Apart from that, water will fail to go inside the pipes and heater because of this type of black.

One of the common ways to determine the problem is by checking the radiators. If the radiators don’t have any hot water, you probably have an air block in any part of the tank.

  • Too Old Expansion Tank

When was the last time you replaced your expansion tank? Expansion vessels generally last around 5 to 10 years, depending upon your usage and maintenance.

As long as your house’s water pressure perfectly matches the air pressure in the expansion tank, using it will be okay. But when you notice a significant difference, replacing it will be the best.

Otherwise, you will notice unwanted noise coming from the tank due to imbalanced water and air pressure. It may lead to hazardous issues if you delay the replacement too long.

  • Waterlogged Expansion Tank

A good amount of air inside the expansion tank is crucial to control the water pressure of your pipeline. But the water inside the tank will absorb a significant portion of air over time.

This will lead to waterlogged issues. As a result, the expansion tank will fail to perform its primary job. Since air gets inside the water, water will fail to expand.

The pressure relief valve will ultimately relieve the excess pressure. You may notice unwanted sounds coming from the expansion tank because of it. Watch this video, for a better understanding.

  • Too Small Expansion Tank

Generally, the size of the expansion tank depends on the water heater. For instance, you need a minimum of 2-gallon expansion tank for a 50-gallon water heater.

However, excessive water pressure in your water system will emphasize using a larger vessel. You may need to use as large as a 4.5-gallon tank if the water pressure is extremely high.

Using too small an expansion tank will put excessive pressure on the system. If you use the water system heavily every day, it will cause pressure buildup. So, gurgling sounds are likely to hear.

Frequently Asked Questions (FAQs)

Should expansion tank make noise?

A well functional expansion tank will create a ticking sound to ensure that it is expanding water. But if you hear unwanted gurgling noise, the scenario might be different. Ensure you install the tank perfectly, and the check valve is working correctly.

What should an expansion tank sound like?

If your expansion tank is working correctly, you will hear two different sounds: a thud sound in the top portion and a hollow sound in the bottom area. Any natural sounds will give an early sign of weary issues, or the unit is not working appropriately.

What happens if expansion tank pressure is too high?

Each expansion tank is equipped with a diaphragm rubber. If the tank has excessive pressure, the tank itself is separated by the diaphragm rubber. But if continuous for a long time, you will notice wear-and-tear for hot water-use appliances that are connected with the expansion tank.

What are the symptoms of waterlogged expansion tank?

If your expansion tank is waterlogged, you will notice dripping issues. Plus, the pressure relief valve may start to release pressure. You may see sediment buildup or Excessive levels of chorine inside the expansion tank if it is waterlogged for a long time.

How often should expansion tank be replaced?

The average lifespan of an expansion tank is 5 to 10 years. It generally depends on the quality, usage, and maintenance. Your water supply line and pipeline connection can also affect the durability of an expansion tank.


Expansion tanks are designed to relieve the hot water pressure in your hot water heating pipes. They are used in your potable drinking supply or hot water supply line.

The purpose of this tank is to ensure constant pressure within the pipes.

Are you still wondering why does your expansion tank make noise? We have already mentioned all the possible causes that can lead to unwanted noise in your expansion tank.

Make sure to address the problem soonest to avoid further damage in the future.

Ralph Wade

Hey...Ralph is here! So, did you find this article useful? If so, please leave a comment and let me know. If not, please tell me how I can improve this article. Your feedback is always appreciated. Take love :)

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