Best Water Separators for Air Compressors of 2021

Updated
Prolong the life of your air compressor with a water separator.

Contaminants can get into your air compressor, causing damage to the components and your air tools. Making sure the water that collects in your air tank is as clean as possible is vital to the long working life of your devices.

Here’s our guide to getting the best water separator for your air compressor.

Our Top Picks

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Model
Compare the Best
Features
Product Image of the Neiko 30252A Water and Oil Separator for Air Line, 1/4' NPT Inlet and Outlet, 90 psi
Best Water & Oil Separator
Neiko Water and Oil Separator
  • Quick-release housing
  • Aluminum body
  • Universal inlet
Product Image of the HEAVY DUTY INDUSTRIAL RATED HIGH FLOW PARTICULATE FILTER, IN-LINE WATER TRAP FOR COMPRESSED AIR LINE SYSTEMS, 5 MICRON WITH METAL BOWL AND AUTO DRAIN (3/4' NPT, 5oz)
Best High-Flow Water Separator
THB Heavy-Duty Water Regulator
  • Maximum of 175 psi
  • All-metal housing
  • Automatic drain
Product Image of the Air Filter, 3/8' NPT wit Quick Release Bowl (Campbell Hausfeld PA212103AV)
Best With Quick-Release Bowl
Campbell Hausfeld Water Regulator
  • Quick-release valve
  • Traps 99.9% of particles
  • 0.375-inch NPT inlet
Product Image of the CrocSee C1.8C.027 1/4' NPT Thread 26CFM Automatic Drain Air Compressor Compressed In Line Particulate Moisture Water Trap Filter Separator with Mount
Best With Auto Drain
CrocSee Auto Drain Water Regulator
  • Auto-drain feature
  • Maximum of 145 psi
  • 0.25-inch inlet
Product Image of the Jewboer Water Oil Separator Air Compressor Filter for Spray Gun Painting Sprayer Air Tools Air Line 1/4 inch NPT Inlet and Outlet
Best Water Separator for Painting
Jewboer Water Oil Separator
  • Attaches directly to the air tool
  • Maximum of 90 psi
  • Made from zinc alloy

Does My Air Compressor Need a Water Separator?

Water separators play a crucial role in protecting your air compressor. Contaminants are harmful to your air tools and can lead to damage and reduced working time. Compressed air contains vapor, which traps in your air tank.

There are variants of what constitutes contamination, but the main ones are:

  • Water.
  • Water vapor.
  • Solid particles.
  • Oil.
  • Oil vapor.

A water separator reduces the level of contaminants within that moisture, leaving your compressor free to do its job while you can drain the water away using the drainage valve.

How Does a Water Separator for Air Compressors Work?

There are two ways a water separator works to remove contaminants. Both are effective, but what are they?

Centrifugal Separators

This type of separator uses a spinning motion to rotate the air inside the tank. This causes the pollution particles to speed up, which pushes them to the outer edge of the tank towards the separator.

Draining the separator is done either manually or automatically.

Coalescing Separators

Coalescing separators use filters to trap pollutants. Compressed air passes through the inside of the filter, pushing it towards the outside, where it gets siphoned away.

Because the filters clog over time, it is advisable to change them regularly if you want to keep the compressor clean at all times.

How To Choose the Best Air Compressor Water Separator?

There are some basic features you should look for when choosing an air separator. Let’s focus on what matters.

What Type of Drain?

The drain is an essential element to your separator. It channels away the water to keep the moisture away from your tools and compressor.

There are 3 types of separator drains you can buy, namely, manual, semi-automatic, or automatic.

Manual

As the name suggests, it involves you checking the moisture levels and draining it away when you need to. On the plus side, manual drains are typically cheaper than automatic versions, but they are less convenient.

Semi-Automatic

A semi-automatic separator releases moisture when there is zero PSI and then closes while the compressor operates to create pressure. These types of drains are less common than the manual versions.

Automatic

This is the most convenient option because it requires no human interaction. When the water chamber gets to halfway, the float displaces and lets the liquid out. The upside is you never have to attend to the regulator to empty the debris.

The downside is they are more expensive and less common than manual drain separators.

Bowl Quality

It’s vital to get a good quality bowl that lasts the distance because it is subject to a lot of pressure. It is one of the most crucial elements of a water separator.

You either get plastic or metal bowls, with the metal ones being higher quality. If you choose the plastic option, make sure the bowl has enough thickness to withstand the process.

Material Quality

Glass makes an excellent separator material because you can see the moisture levels as it fills. It makes it easier to keep a check on the separator. The housing is typically metal. Aluminum and zinc-alloy are also common materials.


The Best Air Compressor Water Separators of 2021

Here are our top 5 air compressor water seperators.

1. Neiko 30252A Water and Oil Separator

Best Air Compressor Water & Oil Separator

This Neiko is our pick for the top water separator, and looking at the satisfaction ratings and the sheer number of sales, it’s easy to see why. It has a 0.25-inch NPT universal inlet, which easily connects with spray guns and air tools.

It’s well constructed, with aluminum housing and brass fittings to maximize the lifespan and a clear polycarbonate bowl so you can see when the filter needs changing. Just press the release valve, and all the debris escapes. It also operates on a maximum working pressure of 90 PSI.

The other great thing about this separator is the price. It sells for a lot less than many similar models, and yet it gets great reviews.

For all-round performance, price, and customer satisfaction, this had to be our top pick.

PROS:
  • Great price.
  • Quick-release housing.
  • Aluminum body.
  • Universal inlet.
CONS:
  • Reliability issues.

Additional Specs

Weight (ounces) 3.52
Dimensions (inches) 6.8 x 5.1 x 2
Max PSI 90 (Comes in a 150 PSI version)
Material Aluminum
Inlet size (inches) 0.25
Price $

2. THB Heavy-Duty Water Regulator

Best High-Flow Air Compressor Water Separator

If you want a separator that handles high flow rates, this could be the best choice. It has a maximum working pressure of 175 PSI and an airflow rate of 140 CFM. This device gives you the option to scale up your tools and get some heavy-duty work done.

It keeps dirt, dust, and oil from entering your compressor tank and damaging your air tools, and thanks to the metal bowl and housing, it is robust enough to take whatever punishment you throw at it.

The NPT inlet is 0.375 inches in diameter, but it does come in a larger 0.50-inch size. It even has an automatic drain that kicks in when the bowl gets to half-full. This saves you precious time and keeps you working as you don’t have to stop to empty the debris from the bowl.

PROS:
  • 0.375-inch inlet.
  • 140 CFM.
  • Maximum of 175 PSI.
  • All-metal housing.
  • Automatic drain.
CONS:
  • Expensive.

Additional Specs

Weight (ounces) 1.65 pounds
Dimensions (inches) 8.78 x 3.58 x 2.87
Max PSI 175
Material Metal
Inlet size (inches) 0.375
Price $$$$

3. Campbell Hausfeld Quick Release Water Regulator

Best Air Compressor Water Separator With Quick-Release Bowl

Campbell Hausfeld is a respected name in the compressor world, so it stands to reason that they should also produce outstanding water separators. This model has a quick release feature that enables you to remove the dirt and debris faster than other models.

Unlike the Neiko, this separator has a 0.375-inch NPT inlet, so it’s slightly wider. The oil filter traps 99.9 percent of all oil aerosols, and the desiccant system removes water vapor, and the outlet screen stops desiccant particles from entering the compressor.

This model stops particles as small as 5 microns and has an airflow of 57 CFM at 90 PSI. This water separator is more expensive than the Neiko, costing over 3 times as much, but when you look at the level of filtering this model offers, you might overlook the price.

PROS:
  • Quick-release valve.
  • Traps 99.9 percent of particles.
  • 0.375-inch NPT inlet.
  • Stops particles as small as 5 microns.
CONS:
  • Expensive.

Additional Specs

Weight (ounces) 8
Dimensions (inches) 3 x 3 x 10
Max PSI 90
Material Metal
Inlet size (inches) 0.375
Price $$$

4. CrocSee C1.8C.027 0.25-Inch Automatic Drain Water Regulator

Best Air Compressor Water Separator With Auto Drain

Finding a water separator with an automatic drain is actually quite rare. Most models are either manual or semi-automatic. This CrocSee model has a drain system that empties when the compressor is idle and seals again when it is under pressure. You never have to worry about contaminants entering your compressor.

This separator cannot match the THB model for airflow and PSI maximums, but it does have a respectable maximum of 145 PSI and a CFM rate of 26. The NPT inlet measures 0.25 inches, and it has a working temperature of 140 degrees Fahrenheit.

It even comes with a wall bracket to help you mount it. Pricewise, this model is more in keeping with the Neiko separator, costing half that of the Campbell Hausfeld version.

PROS:
  • Auto-drain feature.
  • Maximum of 145 PSI.
  • 0.25-inch inlet.
  • Great price.
CONS:
  • Lacks airflow.

Additional Specs

Weight (ounces) 4.8
Dimensions (inches) 4.88 x 2.01 x 2.01
Max PSI 145
Material Metal
Inlet size (inches) 0.25
Price $$

5. Jewboer Water Oil Separator For Spray Gun

Best Air Compressor Water Separator for Painting

When it comes to using a spray paint gun, this Jewboer model is a great choice. It attaches directly to the air port of the spray gun so that you can monitor the separator for dirt and debris. It also allows the vapor to cool as it travels along the air compressor hose and collects in the bowl of the separator.

It has a maximum working pressure of 90 PSI, but with most spray guns, especially HVLP guns, they operate better at a lower PSI. This model stops oil, water, and foriegn objects from finding their way into your air tool.

The inlet and outlet port measure 0.25 inches, and it retails at an incredible price. The downside is while this separator is advertised as NPT, many buyers have complained that it is, in fact, an NPS thread.

PROS:
  • Great price.
  • Attaches directly to the air tool.
  • Maximum of 90 PSI.
  • Made from zinc alloy.
CONS:
  • Not NPT threads.

Additional Specs

Weight (ounces) 3.98
Dimensions (inches) 4.4 x 1.7 x 2.8
Max PSI 90
Material Zinc-alloy
Inlet size (inches) 0.25
Price $

Water Separator For Air Compressor Comparison Chart

Product Best Weight Dimensions Max PSI Material Inlet size
Neiko Water and Oil Separator Water & Oil Separator 4 oz 6.8 x 5.1 x 2″ 90 Aluminum 0.25
THB Heavy-Duty Water Regulator High-Flow 1.65 lbs 8.78 x 3.58 x 2.87″ 175 Metal 0.375
Campbell Hausfeld Water Regulator Quick-Release Bowl 8 oz 3 x 3 x 10″ 90 Metal 0.375
CrocSee Automatic Drain Water Regulator Auto Drain 4.8 oz 4.88 x 2.01 x 2.01″ 145 Metal 0.25
Jewboer Water Oil Separator For Spray Gun Painting 3.98 oz 4.4 x 1.7 x 2.8″ 90 Zinc-alloy 0.25

How To Use an Air Compressor Water Separator?

Knowing how to operate a water separator is vital if you want to get the most from it. Here’s a handy guide.

1. Keep a Distance Between the Tank and the Inlet

The air needs to cool before it rushes through the filter. If it’s hot, it could cause the separator to stop working. You should keep a distance of 50 ft between the tank and the inlet.

2. Mount on the Wall

Connect the L-shaped bracket to the filter and then tighten the bolts. Next, take a block of wood to mount the filter and then attach the whole thing to the wall.

3. Connect the Hose

Making sure the port sizes match, connect the hose to the filter inlet.

4. Run the Air Tools

Connect your hose to the air tool and then join the other to the filter. Switch on the power button, and keep an eye on the moisture levels as you work, especially if you have a manual drain system.

Water Seperator FAQs

How Does Water Get Into Compressor Oil?

Air contains moisture, so as the air compresses, it heats up, increasing the water levels. As the air forces into the tank, water collects and contaminates all parts of the compressor. Added heat creates increased moisture.

Where To Find the Moisture Separator in an Air Compressor?

The water separator should be mounted some distance from your air compressor. It allows the air to cool before it gets captured in the bowl. Most separators are installed on a block of wood attached to the wall some distance from the compressor.

It is not uncommon to find separators at a distance of 50 ft or more from the compressor. This allows the water to cool before it collects inside the separator bowl.

How To Keep Water Out of Air Compressor Lines?

The simplest way is to drain the tank regularly. It stops moisture from traveling along the compressor lines and entering your air tool. Once the compressor cools, the moisture levels reduce.

Do I Need To Change the Water Separator Filter?

You do need to change the water separator filter because it gets clogged over time, which reduces the airflow and risks pollutants entering the air compressor. The best way to avoid mishaps is to change the filter regularly.

However, the regularity of your filter changes depends on how often you use the compressor.


Preserve Air Tools With a Water Separator

Water separators save you a lot of hassle further down the line because they keep the inside of your air compressor and tools squeaky clean. Imagine all that debris inside your compressor without a water separator. Think of the damage it can do and the cost of buying replacement tools.

When you weigh it up, it’s pretty hard to deny that water separators are cheap and they save you money.

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About the Author

Mark Weir

Mark spent 24 years working in real estate, so he knows his way around a home. He also worked with contractors and experts, advising them on issues of planning, investments, and renovations. Mark is no stranger to hands-on experience, having renovated his own home and many properties for resale. He likes nothing better than seeing a project through to completion.
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