We have created this reverse osmosis review site because buying a reverse osmosis filter system is not something that you do on a regular basis. If this will be your first system, selecting the right options can be a little daunting. We have taken a lot of the guess work and uncertainty out of that process by researching many different systems.  From all the systems that we have looked at, we have chosen the top 10 best reverse osmosis water filter systems. The list encompasses a range of filtration options that could all provide you and your family clean, pure drinking water.

Before you start looking at individual systems, it beneficial to spend a few moments looking at our Buying Guide (below) where we explain a few terms that you will come across in your research.

Top Reverse Osmosis Filters

  • 4.7 Customer Rating
  • Home Master TMHP HydroPerfection Under Sink RO System
  • PRICE $$$
  • Nine Stages Filtration
  • Dimension : 12 x 16 x 20 inches
  • Pure water output per day : 75 Gallons
  • 4.8 Customer Rating
  • Home Master TMULTRA Ultra RO Under Sink Reverse Osmosis System
  • PRICE $$$
  • Six Stages Filtration
  • Dimension : 20.1 x 16.4 x 12.3 inches
  • Pure water output per day : 50 Gallons
  • 4.9 Customer Rating
  • Home Master TMAFC Artesian Full Contact Reverse Osmosis Under Counter Water Filtration System
  • PRICE $$
  • Seven Stages Filtration
  • Dimension : 20 x 16 x 13 inches
  • Pure water output per day : 50 Gallons
  • 4.8 Customer Rating
  • APEC Premium 5-Stage Reverse Osmosis Drinking Water Filter System ROES 50
  • PRICE $
  • Five Stages Filtration
  • Dimension : 16 x 5.2 x 17.5 inches
  • Pure water output per day: 50 Gallons
  • 4.8 Customer Rating
  • iSpring RCC7 Reverse Osmosis 5-Stage 75GPD Under Sink Water Filter
  • PRICE $
  • Five Stages Filtration
  • Dimension : 15 x 8 x 18 inches
  • Pure water output per day : 75 Gallons

1. Home Master TMHP HydroPerfection Under Sink RO System

Pure water output per day – 75 gallons

The Home Master TMHP is a full-featured system that includes a permeate pump, which increases the output of the system to 75 gallons per day while at the same time reduces the amount of water needed to flush the membrane. This gives the system a wastewater ration of 1:1, meaning that it wastes only 1 gallon of water for every gallon of pure water produced. The system also has a UV light that will kill off 99.8% of microorganisms and after the water has been filtered it is them passed through remineralization filters. This remineralization adds back a mineral water taste while at the same time reduces the acidity of the water.

The latest system, in addition to an upgraded faucet and the included permeate pump, has a larger 3/8” diameter tubing. This larger bore tubing helps increase the flow rates and the speed at which the pure water is produced.

The modular filters (which include an iron filter) are very easy to change. It is simply a matter of pulling out the old filter and replacing it with the new one – no tools are required. The long life filters used by this system require changing every 12 months or 2000 gallons of water produced.

Although this is one of the more expensive under sink RO systems, it benefits from having a UV light, it remineralizes the water, has a high water output and at the same time is one of the most efficient RO systems in relation to the amount of water wasted to pure water produced.

This TMHP system is suitable for either town or well water.

For further details on this system, check out our full Home Master TMHP HydroPerfection RO system review.

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2. Home Master TMULTRA Ultra RO Under Sink Reverse Osmosis System

Pure water output per day – 50 gallons

The Home Master TMULTRA is a highly efficient RO system that can produce up to 50 gallons a day of filtered water from either city or well water. To produce 1 gallon of filtered water through this system, approximately 4 gallons of water is wasted. This wastewater is used to flush the RO membrane. With higher pressure inlet water, the amount of wastewater can be dramatically reduced. The addition of an optional permeate pump to the system reduces the wastewater to only 1 gallon per 1 gallon of filtered water, while at the same time increasing the system output to 75 gallons per day.

This system also includes a UV light that will kill 99.9% of all microorganisms that pass through it.

The filters are modular in design and to change them all that is needed is to pull the old filter out and push the new one in. Filters typically last a year while the RO membrane requires replacement every 3 to 5 years.

The system is designed to be installed by anyone with reasonable DIY skills.  However, due to the UV lamp, a 110v electric supply is needed for power.

The TMULTRA comes with Home Master’s 5-year limited warranty.

For further details on this system, check out our full Home Master TMULTRA RO system review

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3. Home Master TMAFC Artesian Full Contact Reverse Osmosis Under Counter Water Filtration System

Pure water output per day – 50 gallons

The Home Master TMAFC Artesian RO system solves a problem that some people find with water that has been purified by RO systems; that of the water produced has a bland, unusual taste. This taste is because the water produced by RO systems has no dissolved minerals in it and it is also slightly acidic. After the water has been purified through the TMAFC RO membrane, it is then passed through a remineralization filter twice. This adds minerals back into the water and removes some of the acidity. The end result is a fresher tasting mineral water.

In common with most RO systems, the TMAFC Artesian wastes water to produce the fully purified end result. While the amount of water does vary depending on the feed water pressure, using the industry standard test pressures and temperatures this system wastes 4 gallons of water for every gallon of useable pure water it produces.

The filters, which last for 12 months (or 2000 gallons of pure water produced) are modular in design. This means that the filters pull out and the replacement ones push in without the need for any tools. The RO membrane has a life of between 3 and 5 years depending on the quality of the feed water.

Installation of this system is very straightforward and a person with reasonable skills should be able to complete the install within about an hour. To assist with the installation, all the pipes are color coded to help make sure that they are connected correctly.

For further details on this system, check out our full Home Master TMAFC Artesian RO system review

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4. APEC Premium 5-Stage Reverse Osmosis Drinking Water Filter System ROES 50

Pure water output per day – 50 gallons

APEC Top Tier 5-Stage Ultra Safe Reverse Osmosis Drinking Water Filter System (ESSENCE ROES-50)The ROES – 50 is a very popular under sink RO filtering system. It produces pure water by passing feed water through 3 stages of filtration before the RO membrane. After passing through the membrane the water then goes through a 5th stage coconut shell carbon filter. This final stage removes any remaining taste from the water before it goes into the 4-gallon storage tank. The storage tank is supplied pre-pressurized to aid the flow of water from the faucet.

The ROES – 50, like all RO systems, does waste some water during the process but is more efficient than many other available systems. This system uses about 3 gallons of water to produce 1 gallon of pure water.

Typically, the filters on the first 3 stages need changing about every 6 months, while the RO membrane and the 5th stage coconut shell filter require replacement every 2 to 3 years. The timing of filter changes depends on the quality of the inflowing water.

The system is supplied complete with everything you need to install it and, typically, the system can be installed by anyone with quite basic DIY skills in about 1 hour. To change the filters, a supplied ‘C’ spanner wrench is used to loosen the filter holder, then the filter is unscrewed by hand. The old filter is removed and the new filter is inserted.

For further details on this system, check out our full APEC Water ROES – 50 5 stage system review

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5. iSpring RCC7 Reverse Osmosis 5-Stage 75GPD Under Sink Water Filter

Pure water output per day – 75 gallons

The iSpring RCC7 RO system is one of the higher capacity systems that we have reviewed. It produces 75 gallons of pure water per day. Although this volume will vary depending on the inlet water pressure and temperature. The filtered water is stored in a 3.2 gallon pressurized water tank until it is needed.

The iSpring RCC 7 is a very efficient non-pumped system with regard to the amount that is wasted to produce the pure filtered water. It only uses 2 gallons to produce a gallon of pure water, although this amount will vary depending on your feed water pressure. This compares very favorably with many systems that use 4 or more gallons of water to produce a gallon of filtered water.

The RCC 7 system removes up to 98% of chemicals, heavy metals, sediment, and other contaminants. The filter cartridges last for about 6 months depending on the quality of the feed water and the RO membrane should be changed every 2 to 3 years, again this depends on the quality of the feed water.

The filters are held in clear plastic containers and are located on a central manifold. The filters are easy to change. The filter housing is loosened using the plastic spanner wrench (which is supplied) then unscrewed by hand. The old filter pulls out, then the new filter is inserted and the plastic housing screwed back in.

The system is supplied complete will everything that you need to install it and is designed to be installed in about 1 hour. Basic DIY skills are needed to install the system.

For further details on this system, check out our full iSpring RCC7 RO system review

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  • 4.2 Customer Rating
  • Aquasana AQ-RO-3 OptimH2O Reverse Osmosis Fluoride Water Filter
  • PRICE $
  • Reverse Osmosis Fluoride Water Filter
  • Dimension : 12 x 4.5 x 12.5 inches
  • Pure water output per day : 36 Gallons
  • 4.8 Customer Rating
  • APEC Water Countertop Reverse Osmosis Water Filter
  • PRICE $$
  • Four Stages Filtration
  • Dimension : 14 x 6 x 6.5 inches
  • Pure water output per day : 90 Gallons
  • 4.5 Customer Rating
  • Brondell H2O+ Circle Water Saving Reverse Osmosis Water Filter System
  • PRICE $$
  • Four Stages Filtration
  • Dimension : 13.8 x 9.5 x 16.5 inches
  • Pure water output per day : 56 Gallons
  • 4.7 Customer Rating
  • APEC Water Reverse Osmosis Drinking Water Filter System
  • PRICE $$
  • Five Stages Filtration
  • Dimension : 15 x 7 x 18 inches
  • Pure water output per day : 90 Gallons
  • 4.0 Customer Rating
  • Watts Premier RO-Pure 531411 4-Stage Reverse Osmosis System
  • PRICE $$
  • Four Stages Filtration
  • Dimension : 12 x 4 x 12 inches
  • Pure water output per day : 50 Gallons

6. Aquasana AQ-RO-3 OptimH2O Reverse Osmosis Fluoride Water Filter

Pure water output per day – 36 gallons

The Aquasana AQ-RO-3 OptimH2O RO system is a 3 stage filtration system that also removes fluoride from the water. While the fact that the system has only 3 stages may suggest that it has less filtration than 7 or 5 stage filtration systems, this is not the case. The AQ-RO-3 combines some of the features in a single stage that other systems use 2 stages to carry out.

The system removes over 95% of fluoride and mercury along with 97% of chlorine and arsenic and 99% of lead and asbestos. The data sheet from Aquasana detailing all the contaminants removed can be found here

After the water has been filtered by the system, it then goes through a final stage to remineralize it. This remineralization stops the water from having the RO ‘taste’ and makes it taste more like natural water. At the same time, the pH value is raised from slightly acidic to more neutral.

The system produces 36 gallons of filtered water per day. To produce 1 gallon of filtered water 5 gallons of wastewater are produced. This wastewater is used to clean the RO membrane and the volume of wastewater will vary dependent on the pressure of the feed water. Higher water pressure equates to less wasted water.

This system, which is designed for DIY installation, comes with a 90-day satisfaction guarantee. This means that is for any reason you are unhappy with the AQ-RO-3 system, Aquasana will refund the purchase price. The system also comes with a 2-year limited warranty.

For further details on this system, check out our full Aquasana AQ-RO-3 OptimH2O RO system review

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7. APEC Portable Countertop Reverse Osmosis Water Filter System (RO-CTOP)

Pure water output per day – 90 gallons

The APEC Water RO-CTOP system is the answer to having RO filtered water when the installation of an under sink system is not practicable or when you are in a temporary location. The system is advertised as being “installation free” and this is accurate. All that is needed to get this system up and running is to attach it to a faucet in place of the aerator nozzle.

Although this is a small system in terms of size and weight (it only weighs 7 lbs.) it can produce up to 90 gallons per day. This output is highly dependent on the temperature and pressure of the feed water.

Not only does this system have a surprisingly large output, it is also highly efficient in the use of water. For every gallon of filtered water produced, only 2 gallons are wasted in flushing the RO membrane.

The only drawback with the RO-CTOP system is that it does not have a storage tank that will provide a reservoir of ready to use filtered water.  If the source water pressure or the temperature of the water is low, it can take some time to fill a container pure water.

The stage 1 and 2 filters require replacing about every 6 months depending on the quality of feed water.  The 4th stage filter and the RO membrane need replacing at between 2 and 5 years  – again, dependent on the quality of the feed water.

For further details on this system, check out our full APEC Water RO-CTOP RO system review

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8. Brondell H2O+ Circle Water Saving Reverse Osmosis Water Filter System

Pure water output per day – 56 gallons

The Brondell H2O+ Circle has an innovative approach to the design of the system and looks quite different to nearly every other system on the market. What Brondell has done is to package the system in a sleek container. This means that the number of plastic pipes exposed has been cut down to the minimum.

One of the problems with many RO systems is in knowing when the filters need changing. The frequency of filter changes depends to a great extent on the quality of the inflowing water. A feature on this system that helps is a LED light in the faucet. Under normal conditions, the light glows blue. When the filter needs replacement, the color of the LED changes to red. The light is reset by replacing the battery which is part of Brondell’s filter change kit.

The H2O+ Circle also benefits from a clever design in the reservoir, which in conjunction with a smart valve eliminates back pressure. The advantage to this is that the amount of water needed to clean the RO membrane is greatly reduced. Whereas many non-pump assisted systems will waste 4 gallons of water to produce 1 gallon of filtered water, this system needs only 2.1 gallons to produce 1 filtered gallon of water.

The system itself is designed for a DIY installation. The only possible area that may be a little difficult is in drilling a 1 ¼” diameter hole for the air gap faucet – unless there is already a suitable hole in the sink.

Changing filters is designed to be easy as well, a ¼ turn and the filter is freed.  Replace with the new filter and tighten with a ¼ turn.

For further details on this system, check out our full Brondell H2O+ Circle RO system review

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9. APEC Water Reverse Osmosis Drinking Water Filter System

Pure water output per day – 90 gallons

The APEC Water RO – 90, reverse osmosis (RO) filter system, is the higher output version of the highly popular APEC Water ROES – 50. With a feed water pressure of 60 psi and a water temperature of 77 degrees F, the system can produce 90 gallons of pure filtered water a day. Even with a lower water pressure of 50 PSI, the system can still handle 75 gallons daily.

In this system, a 5 stage filtration process is used. There are 3 filter stages before the RO membrane and once the water has been through the membrane there is a final coconut shell carbon filter to remove any possible residual taste.

In common with all RO systems, there is water wasted. This water is used to flush all debris from the RO membrane to keep it functioning at maximum efficiency and prolong the membrane life. Typically, about 4 gallons is wasted to get 1 gallon of pure water. With the RO – 90 that waste is reduced to 3 gallons per 1 gallon if filtered water, although this figure can vary depending on the inlet water pressure.

The first 3 stages of filters will last, depending on the quality of the incoming water, for between 6 and 12 months while the RO membrane and the 5th stage filter will last for between 2 to 3 years. Replacement of the filters is simple. Just loosen the filter housing with the ‘C’ spanner wrench that is supplied with the kit, then unscrew by hand. Remove the old filter and replace with the new one. Screw the filter housing back into the manifold and tighten with the ‘C’ spanner.

The installation will take on average about 1 hour and all the parts that are needed for the installation are supplied with the kit.

For further details on this system, check out our full APEC Water RO – 90 system review

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10. Watts Premier RO-Pure 531411 4-Stage Reverse Osmosis System

Pure water output per day – 50 gallons

The Watts Premier RO-Pure is a truly modular RO system. All of the filters are connected to the main manifold. This manifold reduces the number of plastic pipes used to connect the filters together. The filters are replaced by lifting each filter away from the vertical, pressing a button and taking the filters off. The replacement filter is then pushed back into the manifold until it clicks.

When the filters are being changed, the valve closes to reduce the likelihood of water leakage. To remind you when to change the filter, the Watts Premier RO-Pure has a very useful indicator light in the faucet, just like the Brondell H2O+ Circle.

There are two 5 micron filters before the RO membrane to remove sediment and debris from the water to help protect and lengthen the life of the RO membrane. After the water passes through the membrane, it then goes through a final carbon filter to remove any possible residual taste and ensure that the water that is dispensed through the faucet has a clean fresh taste.

The Watts Premier RO-Pure also uses water to flush the RO membrane. There are no figures given in their data sheets to say how much water is wasted for every gallon of pure water produced for the RO–Pure but typically, for this type of system, between 3 and 4 gallons of water are wasted to produce a gallon of pure drinking water.

The system, which is supplied with everything that is needed to install it, is suitable for a DIY installation in about 1 hour.

For further details on this system, check out our full Watts Premier RO-Pure system review

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Reverse Osmosis System Buying Guide

When looking to buy a reverse osmosis filter system, there are various terms that manufacturers use that many not be readily apparent to those who do not already own a RO system. Here are a few of the more common terms and what they may mean for you.

TDS

TDS stands for total dissolved solids. In drinking water, TDS is usually comprised of inorganic salts such as calcium, magnesium, potassium, sodium, bicarbonates, chlorides, and sulfates, along with some small volumes of organic matter that are dissolved in water. The EPA sets a maximum level for TDS in drinking water is its Secondary Drinking Water Standards with the maximum level is set at a TDS of 500mg/L.

There are two ways that the TDS can be measured, the first is in a lab under stringent controlled conditions. The second is by measuring electrical conductivity. Although this method is not as accurate as the lab test, the results gained by and fairly inexpensive meter are within 10% of the lab results. An RO system that is functioning well should reduce TDS in water by about 90% – but this is variable.

The best way to know if the filters in your systems are due for replacement is to measure both the pre-filtered and filtered output water to compare the TDS values.
Air Gap Faucet

Air Gap Faucet

Some RO systems come with an air gap faucet, while others offer it as an option. What is an air gap faucet? The air gap provides a siphon break for under sink RO systems. This means that is the sink should get backed up, there is no way that the dirty water can be siphoned back into your RO system. In some localities, it is part of the plumbing code that all RO systems should have an air gap faucet.

While there are advantages to air gap faucets, in many cases a standard faucet is preferred. This is because air gap faucets are more complicated to install; they usually need a hole of about 1 1/1” diameter for fitting, rather than the ½ to 3/8” diameter hole for standard faucets. Air gap faucets need three pipes connecting rather than just one and, in some cases, air gap faucets can be a little noisy.

Water Output

All RO system that we have reviewed use the same standard test for producing their gallons per day output figures. These tests are based on the water being at 77 degrees Fahrenheit (25 Celcius) and with a water pressure of 60 psi. The truth is that in real life installations, very few places have these ideal conditions. This means that quite often the output from a RO system is less (in some cases considerably less) than suggested in the datasheet. It is quite complicated to calculate the exact figures that you can expect to get from any system since lower pressure, lower temperature, and high TDS levels also lead to a reduction.

If your system suffers from the lack of output, you can increase it by adding a pump to the feed water side. A permeate pump in the system will increase output by 50% per day. Additionally, if your water supply is delivered at a very low temperature, introducing some coiled water pipe onto the feed side of the filters will allow the water to warm up before it enters the RO membrane.

pH Values

Most RO systems that we have reviewed cover a wide range of pH values in the feed water. All water from suppliers that comply with EPA Secondary Drinking Water Standards will have a pH value of between 6.5 and 8.5. Water that passes through RO systems tends to have the pH value lowered. This lowered pH makes the water slightly more acidic, which can taste unusual to some people.  If this is a problem for you, you may want to look at systems that remineralizes the water.

This remineralization increases the pH value to nearer a neutral level and adds back some of the taste. Systems like the Home Master TMAFC. pass the water through remineralization filters after the RO membrane. The end result is water that tastes similar to bottled mineral water.

ph values

Wasted Water

One of the complaints about RO systems is that they waste a great deal of water when flushing the RO membrane. Often figures of 20 gallons wasted for every gallon of water produced are cited. These figures are misleading as they often refer to industrial RO systems such as converting sea water into drinking water.

In domestic settings, the figure is more often 4 gallons of water being used to produce a gallon of filtered water. The amount of water used is highly dependent on the pressure of the inflowing water – the higher the pressure the less water is needed to flush the membrane. New designs of RO systems such as the Brondell H2O+ Circle Water Saving reduce the amount of wastewater to 2.1 gallons for every gallon of filtered water produced. A permeate pump, such as that supplied with the Home Master TMHP HydroPerfection Under Sink RO System reduces the wastewater to 1 gallon for every gallon of filtered water produced.

If wastewater is a concern, look for a system with a lower waste to filtered water ratio.  If you want to reclaim the “wasted” water, the waste pipe from the system can be fed into the normal cold faucet or even diverted for watering the garden.

How Do Reverse Osmosis Systems Work?

Reverse Osmosis systems are one of the most effective ways of producing high-quality drinking water. The CDC has prepared a fact sheet about the different systems for purifying water, follow this link to see what the CDC has to say. Here is another informational post that explains what reverse osmosis is.

How Does Reverse Osmosis Systems Works

Although all the systems that we have reviewed are referred to as reverse osmosis systems, the RO part is only part of the system. The RO membrane is, in effect, a very fine filter. To avoid damage to this membrane the water needs to be filtered first. The actual setup varies slightly from system to system and manufacturer to manufacturer but the process is basically the same. While some systems will have additional components such as UV lights, pumps to increase the pressure of the inflowing water, and remineralization functions, the main operations do not vary much.

This animation from APEC Water may help you visualize how a typical under sink RO system works.

Pre-Membrane Filters

In normal drinking water, there are materials that, although invisible to the naked eye, are large enough to damage the RO membrane. Typically, this filter (or filters) will remove all solids such as rust and sand, chlorine, etc. with a 5-micron filter.

RO Membrane

The RO membrane is an ultra-fine filter that filters everything larger than 0.001 microns. This means that virtually the only thing that can pass through the membrane is pure water. There are some dissolved solids that can get through but the membrane can remove as much as 98% of dissolved solids from the water. With the membrane being so fine, it is understandable to see why the water pressure would affect how quickly the water could pass through.

Final Filter

Most systems pass through an additional carbon filter at the final stage to remove any lingering tastes and odors from the water. The purified water is then delivered to a storage tank until required.

Optional Add-ons to RO Systems

UV Lights

Some systems come with a UV light, while it is an optional extra on other systems. The purpose of the UV light is to kill 99.9% of all microorganisms that may be in the water.

Remineralization

Also standard on some systems or added as an optional extra, remineralization adds the beneficial minerals calcium, magnesium, and sometimes potassium back to the water. Not only does this enhance the taste of the water but it also raises its pH value by making it less acidic and more alkaline.

Pressure Increasing Pump

If you have low water pressure or even just want to increase the output of your RO filter system, one option is to add a pump. There are two types of pumps that can be added.  The first is an electric pump and the second type is permeate pump as is used on many Home Master systems such the TMHP. A permeate pump is a clever non-electric device that uses water pressure to increase the water pressure in the system. Not only does this increase the output of the system by 50% it also greatly reduces the water needed to flush the membrane. Instead of using 4 gallons of wastewater to produce a gallon of filtered water, systems with a permeate pump waste 1 gallon to produce a gallon of pure filtered water.

Installation and Maintenance of RO Filter Systems

All the system that we have reviewed (apart from the APEC Water Countertop system) require some degree of installation before they will operate. The APEC system is, as the name implies, sits on your counter top and attaches to your cold water faucet. It is ideal for temporary installations or for taking on holidays or using in an RV.

The remaining 9 systems that we reviewed are designed to be permanently installed with connections into the cold water feed pipes and waste pipes under the sink. Installing any of these systems is very similar and can be easily carried out by anyone with basic DIY skills. The only difficulty that may be encountered is the drilling of a mounting hole for the filtered water faucet.

There are two types of faucets available with RO systems: a standard faucet and an air gap faucet. Note, in some municipalities, it is mandatory to install an air gap faucet with an RO system, although this is widely ignored. Some sinks will have an opening where a spray hose is located or a blanked off hole. If this is the case, this opening can be used for your RO faucet.best reverse osmosis

A standard RO faucet usually requires a ½ to 5/8” hole. The air gap faucet, however, usually requires a 1 ½” opening and this can be beyond the scope of DIY skills, especially if the hole is passes through the counter top. This requirement may affect your choice of RO system. Once the hole for the faucet has been solved, the reaming installation is very straightforward.

Installation

Although there are slight differences from system to system, installation is as follows:

All the systems that we recommend have press fit connectors for the water pipes, this provides a good positive joint without the need for any special tools or knowledge.

Turn off and disconnect the cold water feed pipe from the wall to the faucet.

Attach the supplied ‘T’ connector to the cold water feed outlet.

Reconnect the cold water feed to the ‘T’ connector (and if necessary, the push fit connector – in some cases, it may already be attached).

Drill a hole in the waste pipe for the filter waste connector. In our experience, we found that having the drain connector on a horizontal section of waste pipe reduced the noise when the system is flushing.

Using the drill bit as a guide, attach the drain connector to the drain pipe.

For most models (apart from the Brondell H2O Circle), attach the filter to the side wall of the cupboard (or similar). Make sure that the is enough room below to remove the filters and perform maintenance.

Place the reservoir tank on the base of the cupboard.

Install the filter faucet on the top of the sink.

Attach the water pipes. In most cases, the pipes are color-coded to ensure that the correct connections are made.

If a UV light system is present in the system, plug it into the electrical outlet.

Turn the water on and check for leaks.

Fill and empty the reservoir 3 to 4 times (the exact amount of times depends on the individual system).

The system is now producing filtered water.

Periodic Maintenance

After installation, it is well worth checking the system every day or so to check for leaks. If the system remains leak free for a while, then just check every month to make sure that no leaks occur. This is unlikely once the system is up and running but for the time taken to check it is well worth the effort.

All the RO systems will, from time to time, need periodic maintenance and the intervals are dependent first on the type of system that you have and secondly, on the quality of the water that enters the filters.

All the RO membranes tend to have a life span of between 1 and 3 years. Again the better the quality of the feed water the longer the membrane will last. One area that will help extend the life to the membrane is to always change the pre-membrane filters when needed.

All the systems that we have looked at, although the filters are slightly different, have easy to change filters. In some cases, to replace the filter, all that is needed is to lift the filter slightly out at the base, press a button on the holder and the filter comes away.

Other filters pull out and the replacement just pushes in. Finally, there are the types of filters that are contained in housings and these are unscrewed, the filter cartridge removed, a new one inserted and the housing screwed back in place.

Apart from spending a few minutes every few months replacing old filters, the rest of the system is maintenance free.

RO Brands

In our review of the best RO systems, we have included, as you would expect, the major manufacturers of the top-selling RO systems as well as relative newcomers to the market. On sales volume alone, Brondell would not normally be included. But we have searched hard to find not only what is popular but also what is innovative. 

Home Master

Home Master has been producing RO systems since 2002, originally under the ‘Tap Master” brand. In 2014, it rebranded to Home Master. From the start, Home Master has used modular filters. A modular filter is where the filter and housing are all one unit and this unit is changed as one. Not only does this making filter changes much easier, but it is more effective in ensuring that the housing remains clean of debris that may damage the filter elements.

Many of the Home Master systems come with their “fast flow kit,” which increases the output of the system without increasing the overall size. Another innovation of Home Master is their patented “Full Contact” remineralization system. This Full Contact system treats the water after it has been purified and restores the pH value and adds mineral back into the water. Remineralization effectively gives you mineral water on tap.

APEC Water

APEC, which has been producing RO systems since the late 1990s, stands for Advanced Purification Engineering Corp. and is one of the few RO manufacturers that still produces its membranes and primary filters in the USA. Every RO system that is produced in the California APEC manufacturing facility is thoroughly tested before shipping. APEC RO Systems are highly popular and are among the bestselling and highly regarded systems available.

One system that does deserve special mention is the RO – CTOP system. This system, as can be guessed at from its name, is a portable, counter top RO system. It is small, light, and does not require a permanent installation. This makes it ideal for situations where an under-sink system is not needed, such as in a temporary rental or an RV. Despite its small size, this system can still produce up to 90 gallons per day of pure filtered water.

Aquasana

Aquasana is a Texas-based company that, in addition to RO systems, makes water purification systems for the whole house. The Aquasana that we have reviewed, the AQ-RO-3 OptimH2O Reverse Osmosis Fluoride Water Filter, removes 95% of the fluoride in the drinking water in addition to other contaminants. The water, after it passes through the filtration system is also remineralized to increase the pH value and improve the taste. The system comes with a lifetime warranty if you sign up to their Water for Life program.

iSpring

iSpring produces some of the best value for the money under sink RO systems available. The system that we reviewed, the RCC – 7, has 3 pre=filter stages before the membrane and then a final stage after the membrane to make sure that any residual tastes and odors are removed. iSpring has one of the highest customer satisfaction ratings in the RO market.

Brondell

Brondell, named in recognition of John Brondel, the inventor of a valve to regulate the flushing of toilets, is an innovative company that has products aimed at improving the quality of life in the home. The Brondell RC 100 system that we reviewed is a relatively new system on the market and as such, does not have a great deal of customer feedback. We have included it our reviews since in addition to being a very effective RO system, it brings some innovation with it. The system, unlike other RO systems, is totally enclosed within a neat unit and the only tubes that are exposed are the feed and waste tubes. There is a very cleverly engineered system to increase the pressure on the inlet water and this reduces the amount of water that is wasted in flushing the RO membrane. Despite being a compact unit, the RC 100 will produce 56 gallons per day.

Best Reverse Osmosis Filter Systems Comparison Chart

PRODUCTPRICEFILTRATION
STAGES
WATER OUTPUTDIMENSIONS
Home Master TMHP HydroPerfection Under Sink RO System$$$975 Gallons12 x 16 x 20 inches
Home Master TMULTRA Ultra RO Under Sink Reverse Osmosis System$$$650 Gallons20.1 x 16.4 x 12.3 inches
Home Master TMAFC Artesian Full Contact Reverse Osmosis Under Counter Water Filtration System$$750 Gallons20 x 16 x 13 inches
APEC Premium 5-Stage Reverse Osmosis Drinking Water Filter System ROES 50$550 Gallons16 x 5.2 x 17.5 inches
iSpring RCC7 Reverse Osmosis 5-Stage 75GPD Under Sink Water Filter$575 Gallons15 x 8 x 18 inches
Aquasana AQ-RO-3 OptimH2O Reverse Osmosis Fluoride Water Filter
$3+36 Gallons12 x 4.5 x 12.5 inches
APEC Water Countertop Reverse Osmosis Water Filter$$490 Gallons14 x 6 x 6.5 inches
Brondell H2O+ Circle Water Saving Reverse Osmosis Water Filter System$$456 Gallons13.8 x 9.5 x 16.5 inches
APEC Water Reverse Osmosis Drinking Water Filter System$$590 Gallons15 x 7 x 18 inches
Watts Premier RO-Pure 531411 4-Stage Reverse Osmosis System$$450 Gallons12 x 4 x 12 inches

Wrap Up

We have covered a wide range of Reverse osmosis system reviews. We have not just concentrated on the bestselling models but have also looked for the less popular brands that provide good value for the money as well as being highly effective systems.

We have also taken a look at new and innovative designs that increase the output and at the same time reduce wastewater – one of the most common complaints with RO systems.

Although our reviews have mainly concentrated on fixed, under sink systems, for some people these are not practical. To cover those, we have included a counter top system that attaches to an existing faucet.

We hope that you have found of reviews informative and helpful in guiding you to the best RO system that suits your needs.