Draining is one of the most crucial factors in maintaining an air compressor. It is best to drain the air compressor regularly to keep it free from rust and Corrosion.

But, How to drain air compressor? No worries. Go through the guide, and we’ll get all the answers-

ow to drain an air compressor

What Is Air Compressor Draining?

The stored air inside the air compressor condenses into water. This water settles at the bottom of the compressor tank, affecting the device’s performance. That is why removing this stored water from the tank is essential. And the process of eliminating this stored water from the air compressor is called draining.

However, air compressors have a drain valve that assists the draining system. Read the below section to know the correct way of draining air compressors-

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Ways to Drain an Air Compressor

You can drain your air compressor in two ways- Hand-operated draining & automatic draining. These two processes of draining air compressors are as follows-

Hand-Operated Draining of Air Compressor

It is essential to drain your air compressor daily. To do so, follow the below steps-


Step-1: Turn off the Air Compressor

To drain the air compressor, the very first thing you need to do is turn the air compressor off.

air compressor draining switch

You can turn off the switch of the compressor or unplug it.

Step-2: Check the Tank Pressure

The tank should have some pressure to let the water come out.

If the tank’s valve is at the bottom, the water will come out quickly once the valve is loose. So, check the inside pressure and reduce it to 10 PSI before opening the valve.

However, if the valve of your air compressor is at one side or corner of the tank, it will require air pressure to let the water drain.

In this case, set the tank’s pressure at 30 PSI before releasing the valve. Doing so will increase the inside pressure, and the water inside can get released fast and effectively.

check the tank pressure of the air compressor

Step-3: Keep a Pan Underneath

When the air compressor releases excess pressure through the drain valves, condensed water inside the tank also comes out.

To prevent this dripping water from wetting your floor, use a pan or something else to hold or soak the water.

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pan to se when draining an air compressor

Step-4: Locate the Drain Valve and Open it

The next step to drain the air compressor is locating the drain valve. The drain valve can be at the bottom or side of the compressor tank.

Nevertheless, bottom drain valves are more common and convenient to drain compressors.

Once you have located the valve, loosen/open it to let the condensed water and excess pressure come out.

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drain valve of air compressor

Step-5: Empty the Tank

After opening the valve, you will get a biz sound that ensures the air is coming out.

Let the air and condensed water release from the hole until it’s empty. You
can ensure the tank is empty when no more biz sounds come through the drain hole.

Step-6: Close the Valve

Once you find the tank empty, close the valve tightly. In this step, you must be careful because, if the valve is not closed enough, it will leak the inside air while operating.

To ensure the valve is completely sealed, use tape or thread to tighten them up.

You can also use soapy water over the drain valve and turn the air compressor. If there are any soap bubbles, it indicates the valve is not tight enough.

Test the valve using this trick and take the necessary measures to tighten them.

Now, you know how to drain the air compressor. Follow these steps and drain your air compressor regularly.

Automatic Air Compressor Draining

As an air compressor requires daily draining for better performance, you may get tired of repeating this every day.

So, to save energy, you can get an electronic drain valve that can automatically drain the air compressor.

Managing an electronic draining system is simple and easy. Just follow the below steps to set the valve, and it will do the rest of the work by itself.

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Step-1: Replace the Manual Drain Valve With an Electronic one

Get an electronic drain valve and replace it with the manual one. This type of automated draining valve is excellent for industrial use.

They can empty the heavy-dusty air compressors automatically without any hassle.

electronoic drain valve

Step-2: Set Timer

The draining of air compressors depends on how often you use them. Set the timer of the electric valve depending on the frequency of usage.

The valve will open, drain and close the air compressor as per your settings without the requirement of your observance.

timer of automatic valve

Step-3: Connect the Electric Valve to a Power Source

For operation, the electric valve needs to be connected to a power source.

Therefore, connect the electric valve to a 12-volt power source to let it drain the air compressor automatically.

electronoic drain valve

Step-4: Put a Pan Underneath / Connect the Valve to an Airline

When the drain releases air pressure, condensed water inside the compressor drips out.

Put a pan beneath the tank to prevent water dripping from drowning your floor.

However, it would be best to connect the valve to an airline that will allow the dripping water to run through the tube and drain outside or wherever you set it.

Be Careful While Draining Air Compressor

While draining air compressors, you should take the following safety measures to keep you safe from any accident-


Unplug the Air compressor

un plugging when draining an air compressor

The first and most important thing to do while draining the air compressor is to unplug it. Opening the drain valve when the air compressor operates  may cause a severe accident.

So, ensure the air compressor is unplugged before you open the valve.

Check the Inside Pressure

You must check the pressure inside the gallon tank and bring it to be low before releasing the valve.

If you open the valve when the tank pressure is high, air will propel at high speed, which may be dangerous for you and your surroundings.

Wear Safety Glass

safty glass

Besides air and water, air compressors release dust, debris, or tool grain that can cause harm to your eyes.

So, wear goggles to protect your eyes.

Use Gloves

safety hand gloves

Usually, the drain valve is made of metal that gets hot after running for a long time.

So, using bare hands to open the valves is not wise. Instead, wear gloves and then loosen or open the drain valves for safety.

Tighten the Drain Valves

After closing the drain, valves make sure they are tight enough. If the valve is not closed appropriately, it may leak air and cause serious accidents.

To ensure the valve is tight, use the soap trick mentioned above.

What Happens If You Don’t Drain an Air Compressor?

drain air compressor

Draining an air compressor is essential to keep your device safe and effective.

Air stored in the compressor condenses to water which may rust the tank from the inside. And the rust will eventually cause a hole inside the gallon, causing leakage.

Ultimately, it will affect the air compressor’s performance and cause a higher risk of accidents.

Therefore, to keep your air compressor safe, know how to drain the air compressor and do so accordingly.

What is an Air Compressor Drain Valve?

A Drain Valve in an air compressor is a small device located usually at the bottom of the air tank that flows the water out of the tank.

It releases the condensed water from the bottom of the tank to keep the tank interior dry and free from moisture to prevent rusting.

How Often Should You Drain an Air Compressor?

It would be best to drain the air compressor daily to ensure adequate performance keeping your compressor free from rust and Corrosion.

However, the draining frequency depends on the usage of the machine. If you do not use it regularly, you should still drain it at least once a week.

Why Does an Air Compressor Need a Drain?

The air inside the air compressor condenses into water. This water accumulates at the bottom of the tank and rusts it from inside.

If the tank gets rust, it affects the air compressor’s performance, causing leakage—repair and replacement of which is costly.

A drain valve releases the excess air and condensed water from the air compressor.

That is why a drain is one of the most crucial parts of an air compressor.

How does an Air Compressor Drain Valve Work?

The drain valve is like a tap that releases the pressurized air inside the tank.

The air pressure inside the tank is much higher than the external pressure of the environment.

When you open or loosen the valve, the higher pressure from inside the tank expels in the environment at a higher speed following the effusion process.

Thus, the air and water drain from the air compressor. And this is how the drain valve works.

Where Is The Drain Valve Of The Air Compressor Located?

The valve of an air compressor may locate either at the bottom of the tank or on one side.

However, an air compressor with a drain valve at the bottom is best because it can drain the condensed water from all corners of the tank.

But having a valve at the side of the tank may be tricky to handle, as water from all the corners may not reach the valve. So, tilt the air compressor to release leftover water from the corners in such a case.

Types of Drain Valve In Air Compressors


Types of drain valves for air compressor

You can divide the types of drain valves into two categories. One is the primary manual drain valves, and the other is the industrial drain valves. These are discussed below-

Manual Drain Valves

Manual drain valves are the most basic type of valves in air compressors. There is no indicator in these types of valves. Drain the tank once a day or at least once a week as per the frequency of your usage.

Industrial Drain Valves

Industrial air compressors are air compressors that use various power tools for an impact wrench. The three most common types of industrial drain valves are-


  • Float-operated Drain Valves.
  • Electric Drain Valves
  • Zero-loss Drain Valves


Float-operated Drain Valves:  In this type of drain system, a float can open when water reaches a certain level. Thus, it drains out the water without releasing the process gas.

Float operated drain valves

Electric Drain Valves:  This kind of valve has a timer-set option. They do not check the water level but remove the valve per the timer you set..

electronic drain valve

Zero-loss Drain Valves:  A sensor in this type of drain valve can sense the water level that signals a valve to open the drain. Thus, it automatically releases the water without the flow of compressed air

Zero-loss drain valves

Should You Leave Your Air Compressor Drain Valve Open?

Never leave the air compressor drain valve open. Closing the valve seals the air compressor and doesn’t leak the air.

If you leave the air compressor drain valve open, it will not create pressure inside the tank. As a result, the device will run without doing any practical work.

Moreover, such circumstances will overheat the tank and motor, causing significant damage to the air compressor.

Therefore, always close the drain valve after draining the air compressor. And ensure the valve is tight enough before every use.

Purpose of Draining Your Air Compressor

Draining is the most crucial part of maintaining an air compressor. Below are the purpose for draining your air compressor-

Prevent the Tank from Rusting & Corrosion Regular draining prevents your compressor tank from rusting and
Corrosion. In addition, the air vapor inside the tank condenses to water incooling.

This water is stored inside the bottom of the tank and causes Corrosion to the metal tank.

So, draining the air compressor does not let the water accumulate at the  bottom of the tank and thus saves it from Corrosion and rust.

Save the Tank From Leakage

If the air compressor is not drained regularly, the condensed water inside it rusts the metal tank inside. Ultimately, rusting creates holes in the tank, causing leakage.

Therefore, you can prevent the leakage of the air tank by draining the air compressor regularly.

Saving Repairing Cost

Rusting caused due to not draining the tank causes damage to the air compressor. And it is costly to replace or repair the tank.

Draining the air compressor can save your device from any damage and thus save the repairing cost.

Daily Routine For Air Compressor Maintenance

It is necessary to maintain it correctly to last your air compressor longer. To do so, you can follow the given tips-


After every use, make sure to turn off the air compressor. If the air compressor is turned on, it can cause accidents at any time. Therefore, it is better to unplug the compressor than turn it off.


To maintain your air compressor, accurately draining is an essential fact. It releases the excess moisture stored in the air compressor.

The air inside the compressor condenses to water due to cooling. This water can cause severe damage to the air compressor.

It rusts the compressor tank from the inside and consequently causes leakage. So, to protect the air compressor, draining is a must.

However, it is not necessary to drain the air compressor every day. It entirely depends on the usage of the device. Yet, try to drain the compressor at least twice or thrice a week.


Oil Check

Keeping the oil level in check when you have an oil-lubricated air compressor is essential. The oil inside the pump requires replacement.

If it is not replaced at the proper time, it hampers the device’s performance. So, check the oil level and replace it when it goes below the required level.

You can also follow the color of the oil. Replace it when the oil gets thicker and darker.

If the oil is not drained at the right time, it will start emitting black smoke and making your compressor dirty.


Storing the air compressor should be taken seriously because a moist environment is unsafe for storing air compressors.

If the air compressor is stored in such an environment, it will rust the compressor easily. That is why drain the compressor and keep it in a dry and safe place.

Thus, following these maintenance routines mentioned above, you can take proper care of the compressor and make it last for a long time.

Why Does Your Air Compressor Produce Too Much Water?

The primary purpose of an air compressor is to compress air inside its tank. Then, as time passes, the tank’s air cools down. And the moisture or water vapor gradually condenses to water.

In terms of physics, the higher the pressure is, the higher the rate of condensation. So when you leave the compressor full of high-pressurized air, it condenses faster and produces water.

So, to avoid these situations, release the excess air using the drain valve. Doing this will remove the moisture from the tank, and condensation will reduce.

Storing Of Air Compressor

Once you complete your air-compressing task, it’s time to store thecompressor appropriately.

The first thing you need to do is drain the air compressor. And to do so, first ensure to reduce the air pressure inside the tank. Then unplug the air compressor. Now, put a pan underneath the air compressor and release the valve.

In this way, the excess moisture and water will get released. Thus, your air compressor is ready to store.

Make sure to store the air compressor in a cool and dry place.


How To Drain Air Compressor Oil

An air compressor with an oil-lubricated pump requires oil replacement. First, you need to know the correct process to drain oil from an air compressor. Now, how to drain air compressor oil?

No worries, below I have mentioned the stepwise procedure to drain air compressor oil-

Warm Up The Compressor

The oil inside the tank remains cool at the resting stage. In such a situation, the oil sediments the particles in it and gets thicker. Draining cold oil will be tricky. So, to ensure smooth draining, turn your air compressor on for a while. This step will warm the oil and mix the sediments for easy oil flow.


Once the oil inside the compressor is warmed up, turn off the device. It is essential, as draining the compressor when plugged in can be dangerous.

Place Drain Pan

Now take a drain pan to place it under the drain valve. It could be a funnel or cardboard. Whatever you put under it, make sure it allows a smooth flow of oil to your oil-collecting container without creating any mess.

Lose The Drain Valve

The next step is to lose the drain valve. You can use a screwdriver to lose it. However, use gloves as the oil tank will remain hot.

Darin the Oil

Now it’s time for the final part, which is oil draining. Place the pan beneath the valve and drain the oil into a container. In this stage, wear safety goggles to protect your eyes from hot oil. Further, tilt the compressor a bit to get all oils out properly.

Tightening The Valve

After you are done with oil draining, close the valve and tighten it perfectly. Be careful at this stage. If the drain valve is not drawn correctly, the tank will leak oil, creating a fire breakout. So, make sure you have locked the drain valve.

How To Replace Air Compressor Drain Valve

The drain valves often have issues when used for a long time. If you face such problems without a second thought, take steps to change the valve.

You already know how to drain air compressor from the above discussion. But now, how to replace the drain valve? No worries, I’m here to help you out.

Follow the below steps and replace air compressor drain valve like a pro-

Purchase A Spare Drain Valve

The first thing you need to do is, purchase a spare valve. In doing so, ensure the spare valve fits your air compressor model. You can buy these replacement valves from the market or online.

Drain The Air Compressor

Once you have your spare valve in hand, it’s time to get into the work. First thing first, drain the air compressor. If you remove the valve without draining it, air at high speed will start flowing from the tank, which will be dangerous. So, open the valve and remove excess air from the air compressor.

Remove The Old Valve

Next, use a range to lose the valve from the bottom of the air compressor. When the drain valve comes out, it’s time to replace it with the new one.

Replace The Old Valve With A New One

Take the spare drain valve and place it in the drain hole. Now, secure it with a range. That’s it; your air compressor is ready to reuse.

Thus, following these simple steps, you can change the drain valve easily.

Some Spare Drain Valves for Replacement

If you face any issues with the drain valve, replace it with a new one without any second thought.

Here are some of the spare drain valves suggested for you-


Bostitch Ball Type Valve

Bostitch BTFP72327 Ball Type Drain Valve
  • Ingersoll Electric type Valve

Ingersoll Rand Edv Electronic Drain Valve

Milton Drain Cock

Milton Compressor Tank Drain Cock

Campbell Drain Cock Valve

campbell drain cock valve

Final Word

If you want to keep up the performance of your air compressor and make it last longer, there is no alternative to regular draining.

I Hope, from the above discussions, you now know how to drain air compressor. So, follow the steps accordingly and keep your air compressor rust-free.

However, if manual draining is a hassle for you, go for an automated draining option but still do not skip this step.