10 Best Reverse Osmosis Systems of 2021 Compared & Reviewed

Best Reverse Osmosis System

Since its discovery many decades ago, reverse osmosis has become one of the most efficient and popular methods of water purification.

Reverse osmosis systems work by forcing water at high pressure through a fine semipermeable membrane leaving the contaminants behind. And so with the best reverse osmosis system, you can be confident of getting highly pure and safe water.

These water filtration systems will remove between 95% and 99% of different types of contaminants from small particles and heavy metal to bacteria and pathogens. 

But as reliable as the reverse osmosis system might be, you still need to choose a trustworthy one from a top brand. And in this guide, we help make things easy with reviews of 10 top-rated reverse osmosis systems, and by highlighting the crucial points to consider when buying one.

​What To Check Before Buying Best Reverse Osmosis System?

How to Buy the Best Reverse Osmosis System
Photo: Home Master

Reverse osmosis systems have been in use for treating water in industries and domestically for many years now, and so there are numerous models from different brands in the market. And so to make sure that you buy the best, you need to watch out for the following important things.

1. Filter Stages

The best RO systems will feature multiple stages of filtration, and this is one of the key elements that will set them apart from the many other types in the market.

Most of these systems will typically have between 3 and 7 stages of filtrations. While the more the stages the better as it means more effective cleaning, it is also important to consider the quality of the filter element used and its effectiveness.

For many reverse osmosis systems, the 1st stage gets rid of the larger sediment particles while stages 2 and 3 are for working on the smell, color, and taste.

Stage 4 gets rid of the harmful compounds like arsenic while stage 5 is for improving taste and the optional stage 6 remineralizes the water while stage 7 offers UV light treatment. Hence, a 9-stage system like Home Master TMHP does a much better job.

2. Water Output

The water output or capacity of the reverse osmosis system is measured in the number of gallons that it can produce every day. Many of these systems will typically produce anywhere between 50 and 90 gallons every day.

When it comes to the water output, the best system for you will depend on the amount of filtered water you will need every day or the number of people in your house.

If you want a system with a high water output, it is important to note that you will also need a large tank. In most cases, the high capacity water filters are often the priciest.

To make sure that you get a good reverse osmosis system for your home, you should never settle for anything that cannot produce at least 50 gallons per day.

3. Filter Capacity and Effectiveness

Filter capacity measures the number of gallons that the water filters can clean before they need replacement. Because reverse osmosis systems have multistage filters, they will have different types of filters with different capacities and different lifespan.

The right idea is always to go for filters that are designed to filter the most amount of water or last the longest before you have to replace them. A good system is one that will serve you for at least 6 months before you need to change any of the filters.

Also, consider the cost of replacement filters and their availability when making up your mind because some models use filters that cost almost as much as the entire system.

Read More: Reverse Osmosis System Cost

The quality or effectiveness of the filtration matters as it determines how clean the water will be when it gets to your faucets.

While most brands will claim that their systems will remove up to 99% of contaminants it is a wise idea to use a TDS (total dissolved solids) meter to verify this. Also, you can check for NFS and WQA certifications to determine whether the system is effective or not.

4. Remineralization Filter

Although the water that you get from a reverse osmosis system is highly pure, clean and safe it can also be slightly acidic.

Hence, it is always a wise idea to go for a system with a remineralization filter like Home Master TMAFC to avoid the issues that come with acidic water such as dissolving the rubber inside the water storage tank.

A remineralization filter is designed to add important and healthy minerals to the water such as calcium and magnesium. These minerals not only balance the pH but will also improve the taste.

5. Brands

As you shop for a reverse osmosis system, you also need to consider the brand reputation because some companies are famous for making better quality products than others.

Some of these brands that produce consistently good quality reverse osmosis systems include Home Master, APEC Water Systems, iSpring, and Global Water.

Home Master – Home Master has been making reverse osmosis system for close to two decades now, and they are famous for making units with modular filters to make filter changes quicker and easier. And most of their systems will come with fast flow kit for high water output and full contact remineralization system.

Read More: Home Master TMAFC-ERP Review

APEC Water Systems – APEC has been in business since the 1990’s, and they have been making all their reverse osmosis systems in their USA-based plants in all that time. They have various models in the market including some small, lightweight and portable systems that are highly popular with consumers.

iSpring – Another USA-based company that has been in business for quite some time now and is more famous for under sink RO system that is designed to offer great value for money by being relatively more affordable.

Global Water – Global Water is also a highly reputable brand and they seem to specialize in making countertop RO systems that are super easy to set up and use.

10 Best Reverse Osmosis Systems of 2021 Reviewed




iSpring RCC7AK

1. iSpring RCC7AK (Best Overall)

  • Efficient 6-stage filtration system
  • Removes more than 1,000 different contaminants
  • Delivers clean and great-tasting water
  • Quick fitting connectors for easy installation
APEC Water Systems RO-90

2. APEC Water Systems RO-90 (More Effective & High Capacity)

  • Higher daily water output
  • Simpler and more intuitive filter change
  • Certified to remove more than 1,000 contaminants
  • Free lead-free faucet included
Home Master TMAFC

3. Home Master TMAFC (For Clean & Remineralized Water)

  • Filters and remineralizes water
  • Faster tank refilling
  • More effortless filter replacement
  • Comes fully assembled for easy installation
Home Master TMHP

4. Home Master TMHP (Highly Effective 9-Stage Filtration for Exceptionally Pure Water)

  • More effective 9-stage filtration
  • Remineralization stage included
  • Modular filter design for quick and easy change
  • Reduced water wastage
Express Water RO5DX

5. Express Water RO5DX (More Environment-Friendly)

  • Environment-friendly coconut carbon filters
  • Effective 5-stage filtration
  • Quick connect fittings for easy installation
  • Free replacement filters and faucet included
iSpring RCC7

6. iSpring RCC7 (Premium Quality with Good Output)

  • Premium quality parts
  • Good enough 75 GPD output
  • Quieter operation
  • Easy DIY installation
Whirlpool WHER25

7. Whirlpool WHER25 (High-Performing & More Affordable 3-Stage System)

  • Top performing 3-stage filtration
  • Relatively more affordable
  • Hassle-free filter change
  • Reduces chlorine odor and taste
Global Water RO-505

8. Global Water RO-505 (Inexpensive & Noise-Free)

  • Relatively more affordable
  • Noise-free filtration
  • Simple installation
  • Free replacement filters included
CuZn RO-100-50GPD

9. CuZn RO-100-50GPD (More Budget-Friendly)

  • More affordable RO system
  • Durable stainless steel tank
  • Easy to replace and affordable filters
  • Comes with all components required for easy installation
Aquatron GQM-121

10. Aquatron GQM-121 (Higher Water Output with Minimal Wastage)

  • High enough 75 GPD output
  • Filters with minimal water wastage
  • 100% dry membrane for longer shelf life
  • Quick and easier installation

1. iSpring RCC7AK – Best Overall

iSpring Superb Taste Under Sink Reverse Osmosis System
Photo: iSpring

  • Filter Stage: 6-stage
  • Water Output: 75 gallons per day
  • Filter Capacity: 6 months

iSpring makes their model RCC7AK for homeowners shopping for the best undersink reverse osmosis system. And it is designed to remove 99% of more than 1,000 different contaminants.

This 6-stage filtration system also delivers up to 75 gallons of filtered water which should be more than enough for most families. And its filters have a capacity to filter water for at least 6 months before replacement.

The RO system ensures that you will not only get clean water every time you turn on your faucet but also that it will taste great. The great taste emanates from the remineralization filter that adds important minerals to the water and helps to balance the pH.

You will hardly also hear any sound when this system is in operation as it is super quiet, and it will also require less maintenance.

Installation is straightforward thanks to the quick-fitting connectors and the fact that there is no threading pipe to require. It will also come with everything you need including all the mounting hardware and a brushed nickel faucet.

The thin and quite flimsy O-ring should not be a dealbreaker as it will still last long enough, and you can easily get a cheap and better quality one at your local hardware store.

More Detailed: iSpring RCC7AK Review


  • Efficient 6-stage filtration
  • Includes a remineralization filter
  • Easy DIY installation
  • Quiet and low maintenance operation
  • Beautiful all-metal faucet included


  • Thin and flimsy O-ring
  • Relatively high waste water ratio

2. APEC Water Systems RO-90 – More Effective High Capacity

APEC Top Tier Ultra Safe Reverse Osmosis System
Photo: APEC Water Systems

  • Filter Stage: 5-stage
  • Water Output: 90 gallons per day
  • Filter Capacity: 12 months

The 90 gallons per day water output that you get from this APEC system is the highest in our reverse osmosis system review, and it is also hard to get any other similar size model in the market with a better output.

This water filter also uses some high capacity filters that will serve you for at least 12 months before they need replacement. It is also designed in a way that makes the filter change intuitive and easy.

You can also be confident of getting maximum effectiveness from this system as it has been tested and certified by WQA to be effective in removing 99% of more than 1,000 different contaminants.

When you buy this RO system, you will also get a lead-free faucet and food grade tubing to ensure that you have everything you need to get clean and safe water.

The plastic tank valve is one of the few drawbacks on this system as it is a little flimsy, but it should still hold up well for a long time.


  • High water output
  • Long lasting and high capacity filters
  • WQA tested and certified
  • Easy and intuitive filter replacement
  • High-quality faucet and tubing


  • Flimsy plastic tank valve
  • Not very detailed instructions

3. Home Master TMAFC – For Clean and Remineralized Water

Home Master TMAFC Artesian Reverse Osmosis System
Photo: Home Master

  • Filter Stage: 7-stage
  • Water Output: 50 gallons per day
  • Filter Capacity: 2,000 gallons (12 months)

With a filter capacity of 2,000 gallons or 12 months, this Home Master reverse osmosis system is designed to ensure that it will be a long time before you need to worry about changing filters.

However, replacing the filters is also a fast and efficient process thanks to the modular filter design which is also very useful in preventing water damage.

This 7-stage reverse osmosis system is also designed to produce highly pure water that is remineralized twice before getting to the faucet to give it a great and more natural taste.

The tank also fills up quite quickly, and it is hard to believe that this is a 50 GPD output water filter given the impressive performance. It will come fully assembled and with all the necessary hardware for quick and easy installation.

Being the third most expensive item on our list, this water filter system is quite pricey, but the price is still a bargain for such an effective 7-stage RO system.


  • High filter capacity
  • Modular filter design
  • Adds mineral for a great taste
  • Tank fills up quickly
  • Fully assembled for easy installation


  • Relatively pricier
  • Louder than expected

4. Home Master TMHP – Highly Effective 9-Stage Filtration for Exceptionally Pure Water 

Home Master TMHP HydroPerfection Reverse Osmosis System
Photo: Home Master

  • Filter Stage: 9-stage
  • Water Output: 75 gallons per day
  • Filter Capacity: 2,000 gallons (12 months)

This top-rated reverse osmosis system has a 9-stage filtration system which is more than what you get from all the others in our list, and this is meant to ensure that you get even better water quality.

These stages include a remineralization filter that adds important minerals to the water to balance the pH and improve the taste and UV light to remove microorganisms.

Like most other modern Home Master RO systems, it also uses a modular filter design to make filter change quick and easy. And you will not need to replace the filters for at least 12 months or after filtering at least 2,000 gallons.

There is also a non-electric permeate pump that helps to reduce water waste and improve the production. This efficient system is ideal for use on both well and city water.

However, this is the priciest reverse osmosis system in our list but for a 9-stage water filter, it is worth every buck you will pay for it.


  • Exceptional 9-stage filtration 
  • Relatively higher output and faster flow rate
  • Works for both well and city water
  • Non-electric permeate pump included
  • Modular filter design


  • Quite expensive
  • No visual aids on the instructions

5. Express Water RO5DX – A More Environment-Friendly

Express Water Undersink Reverse Osmosis System
Photo: Express Water

  • Filter Stage: 5-stage
  • Water Output: 50 gallons per day
  • Filter Capacity: 6 months

Besides producing clean and healthy water that is free of up to 99.9% of the major contaminants, this Express Water undersink RO system achieves this using more environmentally-friendly coconut carbon filters.

The RO system also comes with 4 free replacement filters to ensure that it will be a long time before you need to spend any extra cash on it.

This highly efficient 5-stage water filter comes in a quick and easy to understand design and with detailed instructions and all the hardware to make installation easy.

There is also a fast flow faucet included in the package to make this system ready for immediate use, and it also comes with a handy emergency leak detector.

Because the filters do not have a modular design, replacing them can be a little hectic, but you should still be able to do it fast enough.


  • Environmentally-friendly filter material
  • Free replacement filters included
  • Fast flow faucet
  • Quick and easy DIY installation
  • Emergency leak stop detector


  • Filter replacement is a little tedious
  • Directions need some improvement

6. iSpring RCC7 – Premium Quality with a Good Output

iSpring RCC7 Residental Under Sink Reverse Osmosis System
Photo: iSpring

  • Filter Stage: 5-stage
  • Water Output: 75 gallons per day
  • Filter Capacity: 6 months

iSpring makes some of the best reverse osmosis systems and their model RCC7 is one of the most popular ones.

Its popularity stems from the highly efficient 5-stage filtration process that is designed to deliver up to 75 gallons per day which is relatively good when compared to many others and enough for most families.

Like with most other iSpring water filters, it is designed with premium quality parts for a long service life. It comes with everything you need for quick and easy DIY installation. Also, the absence of movable parts ensures a quiet and maintenance-free operation.

The transparent 1-stage housing is also a great addition as it makes it easy to monitor the filters. When you buy this system, you will also get a lead-free, solid brass faucet.

Although it seems to waste a lot of water when filtering, it is still much better than most other RO systems as some can waste upwards of 5 gallons just to make 1 gallon of water.


  • Durable premium quality parts
  • Quick and easy DIY installation
  • Transparent and reinforced 1st stage housing
  • Solid brass faucet
  • Low maintenance and quiet system


  • Higher waste water ratio
  • Tank takes up a lot of space

7. Whirlpool WHER25 – High-Performing and More Affordable

Whirlpool WHER25 Reverse Osmosis System
Photo: Whirlpool

  • Filter Stage: 3-stage
  • Water Output: 18 gallons per day
  • Filter Capacity: 6 months

The Whirlpool WHER25 RO system is a 3-stage water filter that is designed to offer the same level of service and quality that you would get from others with more filtration stages.

This high performing water filter makes use of Ultraease Technology to ensure easy and hassle-free filter change. You will not need to guess when to change the filters as it has a handy EZ filter change indicator.

The Whirlpool reverse osmosis system will reduce the chlorine taste and odor in your water to ensure that you always get a fresh tasting and refreshing water.

When compared to other systems on our list, this is also relatively more affordable. And being the smallest reverse osmosis system it takes up little cabinet space.

The daily water output of 18 GPD is the lowest in our list, but it is still good enough for smaller families and for individuals that live alone. The fewer filtration stages should also not be a dealbreaker as this is still a highly effective water filter.


  • High-performing 3-stage system
  • Relatively more affordable
  • Easy and hassle-free filter change
  • Handy EZ filter change indicator
  • Reduces chlorine taste and odor


  • Low daily water output
  • Fewer filtration stages

8. Global Water RO-505 – Inexpensive and Noise-Free System

Global Water RO-505 Reverse Osmosis System
Photo: Global Water

  • Filter Stage: 5-stage
  • Water Output: 50 gallons per day
  • Filter Capacity: 6 months

Being one of the cheapest RO systems in our list, the Global Water RO-505 is a great choice for those shopping for a high-quality filtration system on a tight budget.

Besides the highly affordable price tag, this is also an efficient 5-stage water filter that is designed to remove up to 99% of more than 1,000 types of contaminants and will filter with little noise.

With the high-quality quick connect fittings, this is also an easy system to install, and it will not require any maintenance.

Filter replacement is also a quick and straightforward process, and you will not need to buy any replacement filters for a while as you will get 4 free ones in the package.

Although the system does not have a remineralization filter, the water that you get is still highly pure, healthy and great tasting.


  • Highly affordable
  • Noise-free operation
  • Easy installation and low maintenance
  • 4 free replacement filters
  • Sturdy, highly durable and compact design


  • Does not remineralize the water
  • Relatively high water wastage

9. CuZn RO-100-50GPD – More Budget-Friendly

CuZn 5-Stage Reverse Osmosis System
Photo: CuZn

  • Filter Stage: 5-stage
  • Water Output: 50 gallons per day

Like most other high performing reverse osmosis systems, this one by CuZn will remove up to 99% of the major water contaminants. It works well for both well and municipal water.

This 5-stage system will deliver up to 50 gallons of purified water every day, and it uses some easy to replace and highly affordable filters.

It is the cheapest model on our list, and so you will not only get a high-quality product but also without spending much on it. It comes with a durable stainless steel tank and a lead-free faucet.

When you buy this system you also get all the components that you need for installation which should be a quick and easy process.

Although it does not have a remineralization filter, the post RO carbon filter still does a great job in improving the water taste and odor.


  • Relatively more affordable
  • Easy to replace filter
  • Works for both well and city water
  • Durable lead-free stainless steel tank
  • Low maintenance


  • No remineralization filter

10. Aquatron GQM-121 – Higher Water Output with Minimal Wastage

Aquatron 5-Stage GQM 121-75 Reverse Osmosis System
Photo: Aquatron

  • Filter Stage: 5-stage
  • Water Output: 75 gallons per day
  • Filter Capacity: 12 months

Aquatron makes this 5-stage reverse osmosis to deliver up to 75 gallons every day which should be more than enough for most families. But what makes it stand out is that it is designed to ensure low water waste with its one to one production ratio.

This water filter system also uses a 100% dry membrane that is designed to maximize the shelf life and the filters will serve you for at least 12 months before they need replacement.

Because this reverse osmosis system comes with all the parts that you need and detailed instructions, the installation should be a quick and easy process. There is also a free brushed nickel faucet to ensure you have everything you need to use it.

This RO system will not remineralize the water, but it will produce healthy and great tasting water, and although it takes up more cabinet space, there should still be plenty of room left in the cabinet for a few other things.


  • Relatively higher water output
  • Low water waste
  • 100% dry membrane
  • Quick and easy to install
  • Free brushed nickel faucet


  • Will not remineralize the water
  • Takes a lot of space

How Does the Reverse Osmosis System Work?

How Does the Reverse Osmosis System Work
Photo: lemoptix.com

Although these systems are referred to as reverse osmosis, the RO membrane or filter is the only place where the reverse osmosis process actually takes place. However, because these are multistage systems, every step has an important role to play.

Here is a breakdown of how the reverse osmosis system works in the different stages.

Stage 1: Sediment Filter

When water enters the system, it first encounters the sediment filter which is meant to block larger contaminants like stones, rust, silt, clay, and dirt.

Stage 2 and 3: Carbon Filters

From the sediment filter, the water that is now free of the larger particles has to pass through two carbon filter stages before getting to the RO membrane. The first carbon filter is for removing most of the harmful contaminants including chlorine. The second carbon filter is denser and more compact to allow it to block any remaining particles.

Stage 4: RO Membrane

The reverse osmosis membrane filter stage is the fourth and most important stage. It is at this point that the system is able to remove even the smallest particles as the water flows through the semipermeable membrane. This membrane will remove elements that are larger than 0.0001 microns. Also, it is at this stage that the suspended contaminants are drained out and pure water is separated.

Stage 5: Carbon Filter

An additional carbon filter makes the 5th stage of filtration and its main role is to improve the taste and smell of the water.

Stage 6: Remineralization Filter (optional)

From the carbon filter at stage 5, some RO systems will also have a remineralization filter. This filter also aims to improve the taste of the water by adding important minerals like calcium and magnesium. Also, remineralization will help improve the pH because the water is often slightly acidic when coming from the RO membrane stage.

Stage 7: UV Light Filter (optional)

Another optional stage that you will find in some advanced reverse osmosis system. The aim of having a UV light filter is to reduce the number of bacteria, viruses and other microorganisms in the water. This makes the water healthier and better suited for human consumption.

How to Install the Reverse Osmosis System?

How to Install the Reverse Osmosis System

Even after choosing the best reverse osmosis water filter system, you need to install it correctly for it to serve you well. And while the installation process can vary from one brand to the other the following are the main steps to follow when installing most systems.

Step 1: Choose an Ideal Location

The first step is always to choose the ideal location to install the reverse osmosis system. Depending on the type of system you have, you can install it on the countertop or under the kitchen sink.

Deciding on the location will let you know whether you need to move anything or make some modifications to the cabinet.

Step 2: Connect Cold Water Line

Once you decide where to place the RO system, what follows are to connect the cold water line to your new reverse osmosis system. There are many options for doing this, but the saddle valve is often the standard method.

Most RO systems will include the saddle valve in the package, and you will need to assemble it on the cold water line. And make sure to adjust the valve which you can do by tightening the belt to make it tight enough to accommodate the pipe’s contour.

Step 3: Drain Line Connection

Next, you will need to install the drain line connection and to do this you have to drill a hole that is about 6 inches above the tarp. Then take the drain clamp out and attach to the pipe but make sure that it is aligned properly with the hole before tightening the clamp.

Step 4: Faucet Space Separation and Faucet Mounting

Because you need a dedicated faucet for the filtered water, what follows are to create space for its installation. If your RO system is from one of the top brands, the chances are that it will also come with a faucet to ensure you do not have to buy one separately.

Make sure that you drill holes to suit the faucet that you want to install by following the manufacturer instructions.

After this, the next step is to mount the faucet also according to the instructions provided by the manufacturer and use a hex nut and lock washer to keep it in place and tighten it with a wrench.

Step 5: Hook Up Color-Coded System

For easy installation, most reverse osmosis systems will come with some color-coded tubes which are in most instances are orange, black, green and blue.

The orange feed water line connects to the saddle valve, the black line will connect directly to the drain clamp assembly, green line to the reverse osmosis water storage tank and the blue line to the faucet.

Step 6: Start the RO System

The last step is to turn on the reverse osmosis system and make sure that you do it step by step and according to the manufacturer’s instructions.

For most RO systems, the water will be cloudy and with some tiny black particles. All you need to do is to leave the faucet running for about 15 minutes to flush out the system after which you should get clear and ready to use water.


Reverse osmosis systems are some of the most efficient types of water filters, and they are known to produce highly pure, healthy and great tasting water.

If you are looking for a high-capacity undersink RO system that will remove most common contaminants, is easy to install and is more fairly priced, the iSpring RCC7AK is our top recommendation.