If you have a compressed air leak, you could be wasting hundreds or thousands a year. Your tools will have a shorter life cycle, and they’ll be less powerful from just a small leak.

Compressed air leaks aren’t easy to spot, but fixing them might be a breeze. You can use ultrasonic detection to find the leak.

To fix the leak, you might opt for replacement parts or tightening the assembly. Let’s take a deeper dive and learn how compressed air works, why it leaks, and how to fix it.

How Compressed Air Works

Compressed air works pretty simply. If you remember back in science class, when gas gets squeezed it starts moving really fast. That’s exactly how air compressors work.

They use a little bit of science to squeeze the air. When the air starts moving, it has the power to push things. This transfer of energy is just like electrical energy in a lot of ways.

When you have a compressed air system, understand that this is pressurized air that is zipping through the lines.

This air is looking for any way out it can find, and the particles are really small. This means that the smallest gap in the assembly could lead to a leak.

What is a Compressed Air Leak?

A compressed air leak is simply when the air leaves the system. If you have a compressor that’s hooked up directly to a tool, it’s easy to understand where it might leak.

It becomes harder when you have many hookups, long lines, or large compressed air infrastructure.

In some spots, you might have planned air leaks. Pressure relief valves, blowers, and exhaust systems are all examples of air leaks. These ones won’t cause you trouble because they’re designed.

The leaks that people are usually talking about are the unplanned air leaks. This is the air that’s escaping in places it really shouldn’t be. But where are these areas?

Most Common Spots for Air Leaks

There are a few places in a system that are usual suspects for air leaks. The rule of thumb is anywhere two objects are connected is a potential place for a leak.

This could be couplings, disconnects, and any kind of fitting.

What Causes Compressed Air Leaks?

As mentioned earlier, the air is desperately trying to escape the system. It will go out of any tiny gap, hole, or opening it can find.

The compressed air system is high pressure (by design), and air prefers being at a lower pressure. Outside of the compressed air line is atmospheric air at typical pressures.

This looks really appealing to the compressed air, and it will use any hole to escape into the more desirable pressure.

So what causes a compressed air leak? Any gap in the system.

Why are there Gaps in the System?

Credit: ExAir

The gap could be there because of a defective part, improper installation, or a part that isn’t the right size. You’ll find a lot of gaps in rubber connection areas.

If the o-ring or gasket isn’t properly seated, there will be a gap.

Another thing to keep in mind is this compressed air is really aggressive to any crack or flaw in the system. The rushing air will degrade the flaw quicker and lead to a leak point.

It could be a simple oversight like putting a dairy fitting in a tube assembly. If the system is welded, there could be a gap in the seam somewhere.

Over time, corrosion could also lead to gaps. How do you locate exactly where the leak is?

How to Spot a Compressed Air Leak

There are a few methods of finding a compressed air leak. Two methods are more primitive, and one method uses some great technology.

You can either listen for the leak, use soapy water, or use an ultrasonic leak detector.

Listening and Feeling

The quickest and easiest way is to rely on your senses. This is easier for bigger leaks in quieter environments.

The leaking air will make a hissing noise. The air blowing out will sometimes be noticeable if you put your hand over the line or a piece of paper.

Soapy Water Test

The next easiest method is using soapy water. You might have seen this method done before and it’s pretty common in household applications.

You put soap in water, then put it in areas you suspect are leaking. The air will create bubbles when the soapy water comes in contact with it.

You can opt to either use a brush or a spray bottle to apply the water to the system.

Ultrasonic Leak Detection

The industry-standard method of detecting compressed air leaks is using ultrasonic technology. These are portable machines that have microphones that listen carefully in a certain direction.

The user will either have headphones connected to the tool, or the tool will have a visual indicator.

The ultrasonic tool is listening carefully for high pitched noises associated with leaking compressed air. The user will scan the tool around the area in question, and the tool will determine if there’s a leak and where the leak is.

Energy Saving Methods

Did you realize that repairing a leaking compressed air system will also save you energy? You’re paying electric costs of running the air compressor.

When you have a leak, you could be losing upwards of 30% of your total air production. This means that 30% of the electricity you’re paying for is going to waste in this system.

By fixing your leaking system, you will be saving energy on your system. On top of that, you’re getting more production from the air you’re making since 100% is going to the tool or machine.

Cost to Repair a Compressed Air Leak

As you’re evaluating the cost impact of fixing your compressed air leak, there are some things to consider. The bottom line is you want to determine if the cost of repairing outweighs the cost you face with the leak.

How Much Money is Leaking Away?

The first thing to understand is how much money are you losing from the leaks alone? Depending on the size of the operation and leaks, it could be a couple of hundred dollars a year or a couple hundred thousand dollars a year.

The first step is to understand how much money you’re losing by not fixing the problem

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Cost of Replacement Parts

If you’re lucky and the leaks are due to improper installation or defective parts, take a look at how much it will cost to replace them.

Replacing a hose, gasket, or an O-ring can cost a couple of bucks.

If you have to replace a valve or tool, the cost might be a little more extreme. Depending on the size and material, it could be a few hundred dollars.

Cost of Detection Methods

Finally, what detection method will you be using? If you are tackling the problem on your own and you’re using soapy water, you’re basically just paying for one of your guys’ time.

The size of your compressed airline and how accessible it is by hand will determine how much this costs. Just multiply the workers’ hourly rate by how long you assume it would take.

Alternatively, you could have an expert come out with an ultrasonic tool. This cost varies due to the size of the compressed air system.

It could be a couple of thousand dollars, or tens of thousands.

Final Cost of Repair

The final cost of your repair is the detection cost plus the replacement parts. Compare this to the money you’re losing from wasted energy, shorter tool life, and less tool power.

This will help make the decision if it’s worth repairing or not.


Compressed air leaks are a pretty common occurrence. They might be easy to fix, but they might not be so easy to spot.

A leaky compressed air system could be costing you tons of money and you don’t even realize it yet. You just learned some of the more common places these leaks occur, how to find a leak, and the cost associated with fixing it.

Now that you know more about compressed air leaks, maybe it’s time to check out your system.