Air compressors and their tools are serious equipment – the last thing anyone wants is to ruin them with dirt and moisture.

That’s where air filters and water separators come in.  But which one is the right one for you?

Below I’ve curated the best of many types of separators and filters into a top shortlist. Each has been chosen for a different reason – whether that’s great value, all-around performance, heavy duty usage, and so on.

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Comparing The Best Water Separator Air Filters

Image Water Separator Thread Type Filter Drain Max Pressure
Pneumatic Plus 3-Stage Water Separator All Both 250PSI
Lematec 303-2 Filter System 1/4" Manual 150PSI
THB Industrial Filters System All Manual 250PSI
SMC AMG350C-N04BC Water Separator 1/2" Auto 150PSI
Alpha-Pure Water Separator All Auto 235PSI
Let’s dive into each of these in more detail.

Water Separators & Air Filters: Detailed Reviews

Best Overall Air Filter

Pneumatic Plus Air Filter Range

These Pneumatic Plus filters are the best on the market, hands-down.

Yes, that’s a bold claim to make. Let me explain.

These filter systems are sold with three parts – 2 regular air filters, and a pressure regulator.

Typically, the air filters are a 10 micron particulate filter, followed by a microscopic 0.1 micron filter.

The first filter handles all the moisture, dirt, and rust particles from the air. The second filter then handles all the micro-sized particles that remain. Once the air’s been cleaned, it’s passed to the regulator so you get the exact pressure you need.

Despite being made up of 3 components, the system is incredibly easy to install. It’s all modular, so it’s simple to add in or take out components as you need. This also makes it super easy to combine with other filters.

However, that’s not why these models are our top choice.

It’s their build quality and universal availability.

Each of the filters produced by Pneumatic Plus are stellar quality. Die-cast aluminium is used which gives fantastic protection and long-life. The polyethylene filters are easily cleanable – you can just feel the all around quality.

I’ve covered this as a ‘range’ because they really do cover all bases. You can get automatic or manual drains, and they’ve got all standard thread sizes.

Pros Cons
Incredible customer satisfactionExpensive
Stellar build-quality
Available in all sizes/types

Our Verdict

Don’t get me wrong – these aren’t the cheapest option.

But if you’re looking for a quality, capable, and easy-to-use filter system – Pneumatic Plus’s range will always be a top contender.

Their product is fantastic. It’s available in every size, and with an automated or manual drain. And their customer satisfaction is second to none.

While it’s not a cheap solution, it’s worth every penny for the avid air-compressor user.

Best Value 1/4"

Le Lematec AI303-2 Air Filter

This cheap and cheerful filter by Le Lematec is the ultimate value filter.

At less than $20, it’s an absolute steal for anyone looking for a quick filter that fits a 1/4″ line.

It won’t give you the same filtration as a $1,000 air dryer system. But that doesn’t mean it can’t give your air a significant step-up in quality.

The filter itself is simple to drain (just push the button!), and easy to clean. Simply undo the nut at either end take the filter out.

The product is heavy, durable (aluminium), and can handle up to 150 PSI of pressure. That’s a lot for a 1/4″ line.

Pros Cons
Durable ExteriorBasic filtration only.
Heavy, reliable product
Unbelievably cheap price
Up to 150PSI in a 1/4" line

Our Verdict

If you’re looking for a simple filter solution, there’s no better value than this model from Le Lematec.

For less than $20 you’re getting a heavy duty, functional filter that’s simple to add and simple to clean.

While it’s not going to change the world, it will give you a good standard of air quality without the massive price tag.

Well worth a try. There’s plenty of satisfied customers to back it up.

Best Heavy Duty Filters

THB Heavy Duty Range

As a level-up to the best value option, these heavy duty filters can handle a step up in volume.

This range by THB covers all thread sizes – with both 5oz and 11oz bowl options.

The larger bowl provides a higher capacity flow rate (circa 170CFM vs 140CFM).  This is similar to the PneumaticPlus system at the top of this post.

For around 20% of the price.

The difference is in the quality of the filter. While the first system goes down to 0.1 microns, this only filters to 5 microns. That said, this is more than adequate for most air tools.

(The filters need to be replaced, which you can buy on Amazon.)

One of the main selling points is the large bowl sizes that come with these filters. At 5 or 11 ounces, they are one of the only manual drains that don’t need emptied every 10 minutes or so. It gives you the freedom to keep working for hours without distraction.


Pros Cons
Can handle high pressures (250PSI)5 micron filter only
Great value priceFilter needs replaced, not cleaned.
Large drain bowl

Our Verdict

This is the best-value heavy duty filter available at the time of writing.

For around $30, you’re getting a 250-PSI capable filter with options for every thread size.

The large bowl can be read through a transparent strip in the side, which makes for great use.

True, it’s not laboratory spec, but for standard workshop use it’ll comfortably get the job done.

Best All-Rounder Water Separator

SMC AMG350C-N04BC Water Separator

If you’re looking for just water separation, then this a real frontrunner.

This model by SNC is one of the best-specialized water separators around.

In terms of performance, there’s no better tool at pure water removal in this price range. You need to go to $1,000 or more units for better.

There are a few limitations – it’s not the best as a filter, and is only available in a 1/2″ thread size.

However, in terms of pure moisture removal, there’s no fanbase or more satisfied customers.

Pros Cons
Fantastic at water removalNot air filter
'Porthole' viewerNot as heavy duty
Stellar customer satisfaction

Our Verdict

If water is your enemy, this is it’s kryptonite.

While it’s not capable at handling as high pressures as other filters, this water separator is fantastic at what it’s made to do.

It’s strongly recommended for anyone who needs to be certain their tools are going to stay dry.

Best Alternative Water Separator

Alpha-Pure Water Separator

I wanted to include this option as a pure water separator due to the massive range of options available.

These brand new separators by Alpha-Pure are still fresh on the market, however all the early signs are good.

They offer a full range – from 15CFM models all the way to 1300CFM(!!) models.

All appear to include automatic drains which activate after there’s a certain amount of liquid within them.

The sepearators use centrifugal devices to force seperation between the air particles and the water. The water then simply collects in the drain, and is sent out automatically.

Pros Cons
HUGE range availableRelatively new to the market. Not as tested.
Automatic drain
Sleek looks

Our Verdict

These units are new, but they also appear to be solid.

Available in every imaginable size, they’re offered a fair price and look to be an excellent choice for water separation.

They’re a real competitor to the tried and tested model above. With the distinct advantage of being available in every thread size and multiple CFM options.


Air tools can be invaluable – and also expensive.

It pays to look after them, so I hope one of these filters or separators has caught your eye. There’s nothing better than the peace of mind you get from knowing your system is complete, and as long-lasting as possible.

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Thanks for reading, and have a great day!