Best Reverse Osmosis Water Filter 2019 | Reviews & Buying Guide

In-Depth Buying Guide & Reviews Of The Top Reverse Osmosis Water Filter (And A Surprising Test Result!)

If you are looking at creating really high quality, contaminant free water then reverse osmosis water filters are a great solution.

Reverse osmosis is a highly efficient method of taking away all the unwanted elements from your water.

Some systems clean up to 99% success rates.

In this guide we discuss in-depth what the best solutions are for finding a reverse osmosis system that works for you.

We analysed the latest equipment released this year, whilst taking a look at the top ranked solutions currently available.

If you have no idea how reverse osmosis (RO) filters work or if you’re looking for in-depth guide then you have come to the right place.

First part of this how to go consists of all the latest reviews. Following the reviews you can find our complete in depth guide that will explain everything to you that you need to know what about RO water filters.

Discover how reverse osmosis works, how to install these systems and look at the latest developments in this type of equipment.

You will discover that RO filters are relatively simple to install and the upkeep is minimal. A quick few checks each month should be enough for you to make sure that everything is working fine.

The most important aspect is that your checking for leaks on a regular basis, to make sure that your system is operating at full capacity.

Best Reverse Osmosis Water Filters Buying Guide

There are a number of Key things that you should consider when you first look at buying a reverse osmosis water filter.

You may not have heard of this type of filter before, or you may not understand what it can offer in terms of water filtration.

But it is important to know all the options available to you. Take your time to read through this entire guide and it will fully inform you on exactly how an RO filter works, and what it can offer you.

The Reverse Osmosis Basics

Before we can start to understand what an RO water filter system is we first need to grasp the basics of Osmosis and Reverse Osmosis.


The beauty of Osmosis is that it occurs naturally.

First let’s discuss osmosis. This process occurs when is stronger saline solution attracts a weaker one.

Let’s take a look at an example. If you look at the image below it shows a container separated by a semi-permeable membrane.


On the one side of the membrane you have fresh water and on the other you have salt or sea water.

The water on the freshwater side will naturally flow towards the salt water side.

This is naturally occurring as any liquid will have a natural tendency to flow towards a higher concentration.

Reverse Osmosis

As it’s name implies reverse osmosis, actually reverses this process. As you can see in the image below instead of the fresh water moving towards the Saltwater.



If we apply a pressurized Force to the saltwater side, then the water is pushed through the semi-permeable membrane. The membrane itself stops contaminates of a certain size, so all the salt and any additional bacteria or debris are left behind. The membrane can track and block many different types of molecule including microorganisms.

So What Are Reverse Osmosis Filter Systems?

Well a reverse osmosis water filter is basically what we have just stated above. It is a solution for purifying water by using semi-permeable and pressurization.

This is too similar to many other filtering methods as it can successfully block out small contaminants, regardless of whether they are visible or not. This means that the final water quality is of a much higher grade.

In fact, reverse osmosis is able to actively remove molecules, ions and also some bacteria.

Reverse osmosis is commonly used in industrial processes for drinking water production. It is an excellent method for recycling any wastewater.

It has the added benefit of being able to remove salt from any type of seawater which is a huge benefit.

How Do Water Filters Using Reverse Osmosis Work?

As with the Industrial process of RO unfiltered water is pressurized from an external source, this pushes the liquid through the semi-permeable membrane.

As the liquid passes through the membrane the majority of contaminants are stopped or redirected to a waste outlet.

The pressure required varies depending on the quality of the water coming in. If water is highly contaminated then the amount of pressure required will be significantly greater.

The water that comes out the other side of the membrane is often cold filtered water. The water is actually demineralised and desalinated. The technical term for this is permeated water.

The result of water is usually of a much higher quality and can contain as little as 1% of the original contaminates.

So What Actually Happens When The Water Reaches The Membrane?

Water molecules are small enough to pass through the semi-permeable membrane easily. Where as the majority of the contaminants are too large to pass through and are stopped. The accumulate and remain on the original side. This rejected or wastewater is then removed using an additional water stream.

Where the wastewater ends up is dependent on the type of filter system used. In the majority of cases the wastewater is simply directed towards a drain. It can also in some instances be sent back to the water source, or it can be automatically recycled so that it does not waste any water.

Most of the time you have the option to use this waste water for other uses.

Reverse osmosis uses a unique method of filtration whereby the water that is filtered goes a completely separate route to the contaminated wastewater. This process is called cross filtration.

This differs from Regular water filtration where unwanted material is collected and absorbed by the actual filter.

Reverse osmosis filters are therefore much more effective and efficient. Left material is left behind than with a traditional method of filtration where build-up can significant issues at a later date.

A Step-By-Step Guide To How The Process Works

The majority of RO systems will use a minimum of 5 steps. Some filtration systems will have many more steps included and can include 10 or more. Regardless of how many steps in total your system has, in the majority of systems the first five steps are the same processes.

Here are the 5 primary steps that all reverse osmosis systems usually have (these steps are not always in the same order) –

Step One – Physical Sediment Removal

The first step is the removal of any large physical contaminants. These can include but are not limited to silt/stones, rust, clay etc. The majority of manufacturers will use five micron filters to perform this process. This size of filter is capable of removing most large contaminants and keeping them away from the semi-permeable membrane.

Step Two – Lighter Carbon Filter

This next step use is the first of two carbon filters. It is designed to remove any chemical compound water that we do not want such as chlorine. Chlorine is commonly in the majority of drinking water as it is used in industrial processes for cleaning water. This step is designed to remove any chemicals that can be harmful to humans and also remove any unwanted tastes to the water.

Step Three – Dense Carbon Filter

This is the second carbon filter in the process and like the first it is much more compact and dense. This part catches much more of the smaller particles in the water. Sometimes the two carbon filters can be combined into one.

Step Four – Reverse Osmosis Membrane

This is the key step in the entire process. In this step the water actually passes through the semi permeable membrane. The membrane is able to catch even the minutest particles. Any heavy metal and radioactive elements still in the water will be removed here. Following this step the remaining contaminated waste water is drained out of the system. Leaving just the filtrated water.

Step Five – Post Filter

You now have the filtered water in a storage tank. Prior to the water going off too the faucet the water will pass through any number of post filters. This again is usually a carbon filter and will remove any remaining smells or tastes. This filter is often called the polishing filter.

Additonal Steps

Depending on the type of filter you buy you may have any number of additional steps added to the process. These additional steps can include –

Mineral Addition

As the water passes through the filtration process all minerals are removed whether they are good or bad. In this step of the process good minerals can be replaced and added to the final filtered water.

UV filter

This is not a commonly step in the process, but it can be an important one. UV filters can be added in order to reduce bacteria and microorganisms in the final filtered water.


Permeate Pumps

Permeate pumps differ from electric pumps in the the do not add additional pressure to the system for the inlet side. Permeate pumps are designed to boost performance. It does this by significantly reducing pressure from the systems storage tank. This results in the reverse osmosis membrane getting full advantage from all the pressure the unit provides.

The term Permeate itself relates to the final water that is output after being through the membrane – the water suitable for consumption.

The premier pump operates bye storing the Hydro power of the wastewater, then converting the energy to push the permanent water under high pressure into the final storage tank.

A common issue with under sink RO units is that they use air pressure to push water through the Faucet. This takes away pressure from the system and reduces efficiency. A permeate pump on the other hand uses the pressure from the wastewater to overcome the tank back pressure and therefore push the permeated water into the storage area.

The results from this system are quite dramatic and create quite a marked increase in efficiency. Using this method the reverse osmosis system can fill the water tank much quicker. Without the down side of back pressure much less water is rejected and the final filtered water is of a much higher purity.

Air Gap Faucets

This type of Faucet was created to allow a physical siphon break between the sink drain and an RO system. The faucet is designed so that if your drain is clogged up, then the gap of air in the reverse osmosis waste line would suck back air rather than contaminated water back into the system.

With this type of faucet, the waste line from the units membrane is directed to the base of the faucet. Hear it drops into a non pressurized area and then continues on via gravity to the drain.

A standard or non-air gap faucet sends the waste line water from the system directly into the drain. This type of faucet it only has a drinking water inlet connected to it.

The main benefit of using the air gap facet is to prevent waste water being siphoned back into the system if a sink is blocked up. In fact you may find that your local area plumbing code requires the use of this type of faucet when using a reverse osmosis water filter.

Remineralization Filters

The resulting water of reverse osmosis is that of almost no mineral or salt content. It is an option to actually add minerals back into your water or remineralize it after going through the process.

This is not essential as most minerals can be found in your food.

If you do wish to remineralize then it is advised to do so with calcium and magnesium. Apart from these two substances, no other mineral (insubstantial enough quantity) is usually absorbed from water into our bodies.

There are a few simple ways that you can add minerals to your filtered water these include –

Adding alkalisation to a system

This is becoming a more common add on too many reverse osmosis filters. If your filter does not already have an alkalisation element and you can simply add one on.

It consists of a filter attachment which has minerals contained within. As your filtered water passes through the beneficial nutrients and minerals are dissolved into your drinking water.

Mineral rich rock salts

This is a physical step which you can take yourself whereby you had a pinch of this salt to each batch of filtered water. You may find that the water’s taste can change slightly. You can alter the amount you add if the taste is not to your liking. Usually though the taste is not that strong for such a small amount.

Trace Mineral Blends

These are often called electrolyte blends. They consist of beneficial minerals such as calcium and magnesium. You can buy these in most stores, they can be mixed manually back into your water when it exits the filter.

Vegetable and plant blends

These minerals are commonly started from plants and vegetables. You may have heard them called Green blends. They can provide a great number of minerals but they can be considerably more expensive to use as they need to be extracted from the vegetables and plants.

They can also affect the taste of the water so they should be used with caution.

External alkaline water filter pitcher

This additional filtering step allows you to store water that has been purified in the pitcher. This then put some minerals automatically back in. This type of picture are very effective at adding minerals. But it can be a more expensive option.

One Stage & Two Stage Filter Systems

One stage filter systems pass through the system once, two stage systems put the waste water through the system for a second time to maximize the water output. You will usually find that a 2 stages has a higher quality water and also a greater total output.

In some two-stage system more carbon dioxide can be removed bye the system introducing caustic between the pass throughs. This caustic increases the ph level of the water and can transform carbon dioxide. If we add a caustic in a single pass system then it would not work as calcium particles would attract to the membrane.

In a one stage RO System, the water that comes into the filter system leaves as partly purified water and part waste water.

In the two stage RO System, water purified from the first filter is collected in a separate area. The drain water then becomes the water in feed for a second pass through.

The pure water that comes from the second pass through is then combined with the water from the first. This increases the amount of pure water at a filter can produce.

Reverse Osmosis System Installation & Upkeep

Reverse Osmosis Water Filter Installation

It is relatively simple to install most reverse osmosis systems. The toughest part can be finding the right size system for your home. You just need to have enough room for everything to fit comfortably.

Most of these permanent systems are simply a case of fitting in place and then connecting up to your faucet.

You can also find portable systems that are even easier to install and can be added to any faucet simply and easily.

Don’t be put off though as most permanent filter systems are relatively simple to install yourself. There are many guides available on the internet, and together with the instructions that come from the manufacturer you should be able to install quickly.


The majority of installation processes follow the same pattern as most manufacturers mainly use the same designs.

If you don’t have the necessary room underneath your kitchen sink to install then you may need to seek help from a plumber in order to install.

If the system is stored in a covered or basement then you may need to extend your water feeds to them. It’s important to remember that these types of system were originally designed to be installed in a kitchen cabinet so if you can find space to install here it would be best.

For the actual installation the toughest part is actually being able to drill a hole to mount the system in place.

You must check with your local authorities to see what the rules are with regards to install this type of system. Some authorities require you to install a system with an air gap faucet, for others you do not need this and a standard force it will suffice.

On some sinks you’ll find a blanking plate that covers an existing hole where a faucet can be installed. This will save you drilling holes as you only need to remove the blanking plate to open up the hole.


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