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An air compressor leaking air from regulator is a very common issue. This article will provide you with why a compressor regulator leaks and what you can do about it. When this occurs, expensive compressed air is wasted and your air compressor will be made to cycle more frequently than necessary, ultimately resulting in energy loss and wear and tear on the compressor.

If you are not certain about what component on your air compressor is the air pressure regulator, or you wish to learn more, visit our guide to learn more about it!

Table of Contents

Air Compressor Regulator Leaking

Sometimes an air compressors regulator, one like the regulator in the image, will leak for a moment or two. If that happens, it’s normal and no cause for concern. An air regulator leaking from weep hole is a common issue, so let’s talk through why this is happening.

Compressed air regulator

Why Does My Regulator Leak Air Periodically?

The reason is that most air compressor regulators are designed to vent or relieve air when downstream pressure is higher than the new regulator setting. But, how does downstream air pressure get higher than the setting on the regulator?

If your regulator was set at 125 PSI for example, and you wanted to dial down the pressure setting to 100 PSI, you would have air in the air line downstream of the regulator at the original 125 PSI. If that was, for example, a 100′ x 1″ air hose, that’s a lot of air at a too-high setting.

If whatever you connected your airline to was susceptible and possibly damaged by higher pressure than the new 100 PSI setting, that 125 PSI already in the hose might cause a problem.

As soon as an air regulator is dialed down from a higher to a lower setting, all of the higher-pressure air in the air hose will vent back up and out the vent on the regulator, until the downstream hose pressure is the same as the new regulator setting.

By venting that higher air pressure out of the regulator relief hole as the downstream setting is turned down, the downstream air pressure will drop quickly to the 100 PSI of the new regulator setting and not leave higher pressure trapped in the line to possibly cause issues.

If it is this venting process that suggests to you that your regulator is leaking, it’s not. It is operating normally at this point.

Why Does My Regulator Leak All the Time?

The scenario that concerns us is one where air can be felt blowing out of the air regulator, and this leaking air continues whether the air compressor is running, or has reached cut-out pressure and stopped. In other words, there is air leaking out of some part of the regulator all the time there is air in the tank.

Most regulators have a diaphragm inside them. It is on this diaphragm that the air pressure, in the line from the tank to the air tool, acts. You can learn more about this in our air compressor regulator guide!

Whether it be a reaction to the compressor lubricating oils, which are not compatible with many forms of rubber, diaphragms, or just stress from too many cycles of increasing and lowering pressure, sometimes this diaphragm inside the regulator cracks and leads to an air leak. One air regulator diaphragm is shown in this next image.

Why A Compressor Regulator Leaks Regulator Diaphragm
Regulator Diaphragm

When this diaphragm cracks, air flow may go through it, up the regulator housing, and out of the relieving hole or flow out from under the adjustment knob. This will happen all the time whether the compressor is running or not, as long as there is air in the tank.

The compressed air will leak until the pressure in the tank drops to the air compressor pressure switch cut-in level, the compressor will start, and since the crack in the regulator diaphragm typically isn’t a large one, the tank will fill to cut out and the compressor motor will stop. The air compressor leaks will continue, however, and this cycle will repeat.

If the leak in the air regulator diaphragm is large enough, the compressor will run and run, but the pressure in the tank will never get to the normal cut-out pressure as much of the compressed air is leaking out of the pressure regulator.

Depending on the size of the regulator in question, and whether it’s a low-cost, Made-in-China chunk of crap or a name-brand that may, coincidentally, also be made in the Orient, you may or may not be able to get parts for the regulator to enable you to disassemble it and replace the diaphragm.

We do have guides on air compressor pressure regulator troubleshooting & air compressor regulator repair, which are worth a read!

That being the case, it may be time to replace the regulator. The mini air regulators are available from many locations including online and are not expensive. Often, you can acquire one for under $15 plus shipping.

It may be better to replace the regulator than waste the time and energy trying to find parts and then figuring out how to disassemble and then reassemble a compressed air piece of equipment that you may not be at all familiar with doing. Unless it’s a $100 regulator from an industrial source, that is, but then, those sources will have parts and instructions on how to fix them, too.

FAQs (Frequently Asked Questions)

Why is my regulator leaking?

The most likely reason your regulator is leaking is due to the diaphragm inside the regulator. Whether it be a reaction to the compressor’s lubricating oils or just stress from too many cycles of increasing and lowering pressure, sometimes the diaphragm cracks and leads to an air leak.


If you have any questions regarding an air compressor regulator leaking, please leave a comment below, with a photo if applicable, so that someone can help you!