Compressing air creates a water problem. All air contains water vapor. Compressing that air forces that water vapor out and the water must collect somewhere in your compressor. The logical point for the water to collect is the air tank.

Air compressor manufacturers put a drain valve on the bottom of the air tank for a reason.Your regular shop maintenance routine should include draining that air tank on a regular basis. Even if you are diligent, there is still a problem.

Water Separators are designed to remove contaminants from the compressed as it leaves the air compressor and before it gets to your tools. In this detailed buyer’s guide, we will look into the best water separators based on the application.

Below, we included the most common water separators. However, if you have an industrial air compressors, you will need a certified tech to choose and install your water separator. Fill out the form below for a free quote.

Most Common Air Compressor Water Separators

1.PneumaticPlus SAD4002 Water SeparatorBest Overall

Our pick for the best overall water separator is the PneumaticPlus SAD4002.For general compressed air use on a job site or in a shop, you can count on this piece of equipment to keep the rest of your air tools clean and dry.

With the PneumaticPlus water separator, you get the full package of features at a nice price. This water separator for your compressed air system has all the features that you want for the protection of your tools without busting your budget.

  • Automatic drain
  • Float drain includes a ¼” tube connection
  • Metal bowl and housing
  • Sight glass
  • ½” NPT Female Thread ports
  • 10-micron filter element
  • No electricity required to operate the automatic drain.


  • High-quality construction with an eye to details
  • A convenient sight glass for quickly checking the separator
  • It empties when the air pressure is removed which is a great feature


To be honest, we couldn’t find any negative comments about the compressed air water separator. For the price, this is a great way to protect your air tools from contaminants in your compressed air supply.

PneumaticPlus SAD402-N04D-MEP Compressed Air, External Water...
  • Automatic drain for removing accumulated liquid from a compressed air system
  • Float Drain w/ 1/4" Tube Connetion (Push-to Connet Fitting) & Metal Bowl w/ Sight Glass
  • 1/2" NPT Female Thread ports for use with existing air piping, 10 Mcron Element

Last update on 2021-11-20 / Affiliate links / Images from Amazon Product Advertising API

2.PneumaticPlus SAU3030M-N03G-MEPThree Stage Air Drying System – Best For Painting

If you intend to spray any kind of finish, whether it is automotive paint or wood lacquer, you need to make sure that you are delivering the highest quality air to your paint gun possible.

Contaminants in your air supply can cause issues such as fisheye, finish pop, and others.To get this higher quality of air with the required airflow and pressure stability, you should consider the PneumaticPlus SAW3030< Three Stage Air Drying System.

The quality of air that the PneumaticPlus SAW3030 delivers to you spray booth will ensure that your finishes are as near perfect as can be accomplished. This three-stage unit includes:

  • Maximum pressures up to 250psi with a maximum operating pressure of 150psi
  • 16scfm flow rate at 100psi
  • Includes a 10-micron filter element and a .3-micron coalescing filter element for the driest and cleanest possible compressed air.
  • Manual drains and metal bowls
  • The regulator keeps pressures stable and has an easy to read gauge
  • No moving parts and no electricity required


  • Accurate regulator with automatic blow off so the gauge always reads accurately
  • Well-constructed and tough. Easy to mount and install.
  • Can easily be reconfigured for custom installations.


  • Manual drain
  • In high humidity areas, it fills up quickly
PneumaticPlus SAU3030M-N03G-MEP Three Stage Air Drying...
  • Max. Supply Pressure: 250 PSI, Max Operating Pressure: 150 PSI
  • SAF:10 Micron Element Stanard/ SAFM: 0.3 Micron Coalescing Filter Element
  • Manual Drain & Metal Bowl with Bowl Guard/Includes 0-150 PSI Pressure Gauge & Bracket

Last update on 2021-11-20 / Affiliate links / Images from Amazon Product Advertising API

3.LE LEMATEC Air Compressor Filterand Water Separator – Best For Money

For those compressed air systems that get only occasional use, a more economical solution to trapping and removing contaminants from your compressed air supply may be the best choice.

If you only use one pneumatic tool or you are interested in putting dry air into your car tires,an inline water separator may be your best choice.

The Le Leatec Inline compresses are water and oil separator is convenient to use and provides a budget-conscious means of providing clean air at the end of your air hose or at the inlet of your air tools.

Le Lematec AI303-C1 Air Compressor Filter Oil Water...
  • Le Lematec air compressor filter oil and water separator works with any air compressor and air tool. The air filter traps dirt oil and moisture as a receiving filter for air tools.
  • Keep air tools in tip top working condition and prevent costly repairs by preventing dirt and moisture from damaging your air tools and accessories
  • LE Lematec air dryer is a heavy duty inline air filter. Made from aluminum with solid brass fittings, it offers excellent reliability. Features a 1/4 inch air inlet “female” and 1/4” “male”.

Last update on 2021-11-20 / Affiliate links / Images from Amazon Product Advertising API

This small separator can be mounted to your tool or the end of your air hose.

  • Traps water, oil, and dirt
  • Shock-proof and durable
  • Convenient push-button drain
  • All brass fittings and metal housing
  • Comes with a money-back guarantee
  • Replaceable filter element


  • Simple, easy to use, and install.
  • The push-button drain system is ingenious
  • Small size is handy in a shop with limited space
  • Cheap enough to mount one on each of my air tools


  • It’s small and fills with water very quickly
  • Airflow may be restricted

4.THB ½” Heavy Duty Particulate Filterand Moisture Trap – Best For Auto Drain

Getting an automatic drain on a reasonably priced water separator can be a challenge. Most of the low and mid-range compressed air water separators suitable for home or hobby shops are just too expensive to easily justify.

However, THB has an offering that might just suit your needs.The THB 1.2” heavy-duty particulate filter and moisture trap is a well-built and durable water separator that comes standard with an automatic drain system at a price that won’t make you flinch.

THB 1/2" Heavy Duty Particulate Filter Moisture Trap Water...
  • HEAVY DUTY 1/2" Compressed air line Filter seperator/Particulate Filter
  • 1/2" Female NPT Air Inlet port X 1/2" Female NPT Air Outlet port
  • With Internal Float Drain 140 CFM Flow Rate

Last update on 2021-11-20 / Affiliate links / Images from Amazon Product Advertising API

It isn’t short on features either.

  • Heavy-duty construction for long life and durability
  • ½” female NPT fittings
  • Internal float drain
  • 140cfm flow rate
  • 215psi maximum out pressure
  • 250psi maximum input pressure
  • Sight glass on the bowl


  • Easy installation
  • Well-constructed
  • Works well
  • The auto drain is fantastic


  • The float value sometimes sticks and doesn’t drain

5.PneumaticPlus SAF600– Best For High Flow Rate

If you run a shop where large flows of clean and dry compressed air required to keep machinery or larger tools operating, you need a high flow compressed air water separator in your system.

High flow rates can generate more water that lower airflow rates. A well-designed water separator can save you hundreds or thousands of dollars in downtime and maintenance costs.

PneumaticPlus SAF600-N10BD-MEP压缩空气的部分iculate...
  • Max. Supply Pressure: 250 PSI / Operating Pressure: 0 to 150 PSI
  • 10 Micron Element / Flow Rate: 460 SCFM @ 90 PSI
  • Auto Drain, Metal Bowl w/ Sight Glass, Port Size: 1" NPT

Last update on 2021-11-20 / Affiliate links / Images from Amazon Product Advertising API

The PneumaticPlus SAF600 High Flow water separator installed in your air system can be what saves you from those additional costs.These water separators are designed for the task of dealing with water, oil, and particulates in high airflow situations.

The features included reflect that design.

  • Automatic drain
  • Metal bowl and housings
  • Sight Glass
  • 10-micron filter element
  • Includes mounting bracket
  • Large airflow rate up to 460cfm at 90psi
  • Maximum supply pressure 250psi
  • Operating pressures 0 to 150 psi
  • 1” inlets and outlets


  • Easy to mount and install
  • All-metal housing and bowl are resistant to solvents
  • Easy to change the filter
  • Automatic drain means less maintenance


  • If you don’t change the filter regularly, it restricts the flow rate

What is an Air Compressor Water Separator?

Water Separators are designed to remove contaminants from the compressed as it leaves the air compressor and before it gets to your tools. These contaminants can include:

  • Liquid water
  • Water vapor
  • Solid particles
  • Oil
  • Oil vapor

How do Water Separators Work?

There are two different methods by which compressed water separators remove contaminants from the compressed air in your system. Both are effective at removing the contaminants from your compressed air supply.

Centrifugal Separators

Centrifugal separators are designed to induce a rotary or spinning motion to the compressed air as it passes through the separator. This action causes the contaminants to speed up.

As the particles, oil, and water speed up, they more to the outer edge and collect on the inside of the separator housing where they drain to the bottom and can be drained.

Draining the centrifugal air separator can be done either manually of with the installation of an automatic drain system.

Coalescing Separators

Coalescing separators utilize a filter element to trap contaminants in your compressed air supply as it moves through the filter.

The compressed air is forced through a filter medium from the inside of the filter to the outside, where the compressed air exits the separator. You must replace these filter elements on a regular basis.

Keeping Your Air Dry and Clean – Our Picks for the Best Compressed Air Water Separators

Different situations and installations call for different types and sizes of water separators.

We have searched and considered many different makes, models, and types of water separators for each use, and these are our picks as the best for each application.

Frequently Asked Questions

Other Issues Solved By Water Separators

As you are working, the pressure in your air tank varies up and down, and it streams air down the connection hose to your tools.

As the pressure varies in the tank, the air picks up water vapor that ends up in your valuable tools.

Water in the cylinders of air tools makes for bad results over time, even if you are careful to oil those tools with each use.

You need to think about protecting those tools by removing that water from the compressed air before it can reach your tools and do more harm.The answer is to install a water separator on your compressed air system.

This will ensure that you are delivering clean, dry air to your tools.

Do I need a water separator?

If you use compressed air, even if only to inflate your tires, you should have a water separator installed on your compressed air system.

Most people don’t realize how destructive water can be to tools and even to tires. Water can rust or deteriorate tools and tires, shortening their life.

Where does the water in my compressor tank come from?

As the air pump compresses the air, it heats up. In the air tank, as you use the compressed air, it cools and any water vapor that was in the compressed, heated air condenses on the inside of your air tank and collects at the bottom.

The water will eventually corrode the tank and can potentially be carried down the air hose to your tools.

Keeping Things Dry

In the end, it is all about protecting your investment in the tools and other uses of your compressed air. Keeping water, oil, and other contaminants from migrating down the system and into your tools are the goal.

No matter whether you are a casual hobby compressed air user, or you run a shop that uses high volumes of compressed air, it is in your best interest to install a water separator on your compressed air system.

We hope that this article has answered some questions and given you the information that you need to decide on whether to install a compressed air water separator.

If you do decide that your system needs to have a water separator installed, the information here can help you find the best water separator for your needs.