The 10 Best Reverse Osmosis Systems: Reviews & Ultimate Guide

This is our review of the best Reverse Osmosis system of 2023.

If you are looking for clean and healthy drinking water you need a good water filtration system for your home, and a Reverse Osmosis system is a great choice as it removes up to 99% of harmful contaminants, giving you and your family safe and healthy purified water to drink.

But there are several factors to consider when looking for a Reverse Osmosis system, like the number of filtration stages, if it remineralizes the water (i.e., adds back minerals like calcium and magnesium), the daily water output (relevant if you have a large family) and the quantity of waste water generated.

Typically RO systems are installed under the kitchen sink, but there are also countertop and portable RO systems that could be good choices for different situations.

With all these important factors in mind, we invested long hours reading & researching to find out the best overall Reverse Osmosis system, and also the best RO option for different situations.

So, after extensive research, we found that the Waterdrop G3P800 Reverse Osmosis System is the best overall choice for a Reverse Osmosis system.

But every situation is different, so we also reviewed the best RO systems in every category.

Let’s get started!

Our Top Picks for Best Reverse Osmosis Systems

10 Best Reverse Osmosis Systems Reviewed

After spending a long time researching and reviewing several Reverse Osmosis systems, we identified the 10 best options for different purposes.

We've invested the time so you don't have to:

  • Best for: Overall
  • Filtering Stages: 7
  • Dimension: 18.1 x 5.7 x 17.8 inches
  • Weight: 20.5 pounds
  • Efficiency Ratio: 3 gallon filtered:1 gallon
  • Gallons per Day (GPD): 800
  • Tank Capacity: Tankless
  • Remineralization: Optional bundle

For us, the Waterdrop G3P800 Reverse Osmosis system is the best overall and we highly recommend it because it is an exceptional RO system that offers superior performance and features.

One of the key advantages of the Waterdrop G3P800 is its tankless and compact design, which saves space and makes it easy to install. This RO system also provides instant water on demand without the need to wait for the storage tank to refill, which is a common issue in other RO systems.

The Waterdrop G3P800 comes equipped with smart monitoring features, including an LED ring on the faucet that glows in different colors to indicate the status of the water filters. Additionally, an LCD panel displays the TDS level of the water in real-time, allowing you to monitor the quality of the water you are drinking. The system also has an automatic flushing capability that self-cleans the system when needed, ensuring that the water remains fresh and clean.

The Waterdrop G3P800 has an internal built-in pump that allows for faster water flow and a production rate of up to 800 gallons per day, which is much higher than the 75 GPD of other RO systems with a storage tank. This RO system also has a waste water ratio of 3:1, which means it only wastes one gallon of water for every 3 gallons of filtered water produced, making it the most efficient RO system in the market.

The Waterdrop G3P800 is NSF 58 and 372 certified, ensuring that it is capable of removing most contaminants from the water, including heavy metals, fluoride, and limescale. The system is also lead-free, making it safe for consumption.

If this model is too expensive for your budget, or if you don’t need so much filtered water available per day, you might consider Waterdrop’s previous model which is also great, the Waterdrop G3.

While this product doesn’t include a remineralization stage by default, you can always buy it as an optional bundle. You can connect the Waterdrop MNR35 RO remineralization filter to ensure that you have all the necessary minerals in your water.


  • 7-stage filtration system
  • Compact and sleek design
  • Tankless system for on-demand filtered water
  • LCD panel with real-time TDS monitoring
  • LED ring indicator for filter replacement
  • Automatic flushing system for easy maintenance
  • 3:1 waste water ratio
  • High daily water output of up to 800 gallons per day
  • NSF certified
  • Easy installation process


  • Higher price point compared to some other RO systems on the market
  • Some customers have reported slow water flow
  • No built-in remineralization feature

Promo: Use our code WFPG3P800 for a $55 discount on the Waterdrop website

  • Best for: Overall (Runner-up)
  • Filtering Stages: 6
  • Dimension: 16 x 5.25 x 17.5 inches
  • Weight: 27 pounds
  • Efficiency Ratio: 1 gallon filtered:3 gallons
  • Gallons per Day (GPD): 75
  • Tank Capacity: 4 gallons
  • Remineralization: Yes

While not as good as the Waterdrop G3, the APEC Water Systems ROES-PH75 Essence Series is a great RO system. It delivers 75 gallons per day of purified water through a 6-stage filtration process with remineralization, comes with a flow restrictor and automatic shut-off valve, all of this at an extremely competitive price.

The APEC Water Systems ROES-PH75 Essence Series uses a 6-step filtration process, in which on the last stage minerals lost in previous stages are added back to the filtered water, raising the pH, making it tastier and healthier.

Another positive point of this system is the easy installation process, as it comes with a step-by-step guide and video tutorials to make sure that you can install the RO system on your own. Just make sure that you have enough space under the sink for this system, as it comes with a pressurized tank.

We just don’t like the waste water efficiency of 1:3, wasting 3 gallons of water for each gallon of purified water, but it is a typical efficiency amongst RO systems.

The last thing worth mentioning is that this device comes with a 2 year extended manufacturer’s warranty, with registration.


  • Price
  • Remineralization
  • Easy installation
  • Easy connection to refrigerator
  • 2-year extended manufacturer’s warranty
  • WQA certified
  • Filters longevity


  • Low waste water efficiency
  • May require an additional pump
  • Some customers mentioned the faucet quality
  • Best for: Budget
  • Filtering Stages: 5
  • Dimension: 16.18 x 18.75 x 18.06 inches
  • Weight: 11.8 pounds
  • Efficiency Ratio: 1 gallon filtered:3 gallons
  • Gallons per Day (GPD): 50
  • Tank Capacity: 3.2 gallons
  • Remineralization: No

If you are on a budget, the Express Water RO5DX Reverse Osmosis system is the right choice for you. And being cheap doesn’t mean low quality, as this NSF certified RO system delivers top filtration efficiency with a 5-process capable of removing the most harmful contaminants of your water.

It doesn’t remineralize your filtered water, but is customizable and upgradable which allows you to add additional filters, like an alkaline filter to add minerals back to your water.

This RO system is easy to install, and comes with pre-assembled filters and concise easy-to-understand instructions to allow you to quickly complete the process by yourself.

It also includes a leak detection system that shuts off the water flow if it detects excess water, which can give you some peace of mind.

The Express Water RO5DX system is able to provide 50 gallons of filtered water per day, which is not bad but is on the low side compared to other systems in our guide. If you have a large family you should consider if this quantity is enough for you.


  • Price
  • NSF Certification
  • Easy installation


  • Low waste water efficiency
  • No remineralization
  • Low GPD
  • Best for: Countertop
  • Filtering Stages: 4
  • Dimension: 18 x 18 x 15 inches
  • Weight: 22.7 pounds
  • Tank Capacity: 1.3 gallons

The AquaTru Countertop RO system is an ideal choice for a countertop system, as this NSF certified system delivers great water filtration capacity through a 4-stage filtration process capable of removing 82 different contaminants (like lead, carcinogens, chlorine, copper, etc.) without sacrificing undersink space and without the need for installation and plumbing.

The device has a modern device that fits well in kitchen countertops, and its removable tank allows you to store the purified water in your fridge, if you prefer cold water.

The system takes 1 gallon of feed water that needs to be filled manually, and then takes between 12 to 15 minutes to filter the water.

Another nice feature of the The AquaTru Countertop system is that it comes with a digital display that lets you know when it’s time to change the filters.

This device doesn’t require installation or plumbing, which is super convenient and makes the process of acquiring a RO system seamless.


  • Cool design
  • No installation required
  • NSF certified
  • Removable dispensing tank
  • Good waste water efficiency


  • Small holding tank
  • No remineralization
  • Some customers complained about intermittent shut-offs
  • Best for: Undersink
  • Filtering Stages: 6
  • Dimension: 15 x 8 x 18 inches
  • Weight: 7.13 pounds
  • Efficiency Ratio: 1 gallon filtered:3 gallons
  • Gallons per Day (GPD): 75
  • Tank Capacity: 3.2 gallons
  • Remineralization: Yes

The iSpring RCC7AK 6 Stage Reverse Osmosis System is a good choice if you need an undersink RO system, as this easy-to-install and certified system offers a 6-stage water filtration process with remineralization at a competitive price.

The alkaline remineralization filter restores healthy minerals removed by the RO membrane, which balances the pH of the water making it less acidic.

Several customers mentioned that the DIY installation of this water filtration system is easy and straightforward, supported by physical and online manuals and videos, and they also offer phone support.

The iSpringRCC7AK system has many of the traditional RO systems features, like a pressurized storage tank, so make sure you have enough space under the sink to fit this system before you buy it.

A nice feature is that the 1st stage housing is transparent, which allows you to visually check the sediment filter and know when it needs to be changed.

But not everything is positive in this product, it has a low efficiency compared to other products in this guide, with a 1:3 waste water ratio.


  • Price
  • Easy installation
  • Remineralization
  • NSF and WQA certified


  • Low waste water efficiency
  • Some customers complained about leaking
  • Best for: Drinking Water
  • Filtering Stages: 7
  • Dimension: 12 x 16 x 20 inches
  • Weight: 14.5 pounds
  • Efficiency Ratio: 1 gallon filtered:1 gallon
  • Gallons per Day (GPD): 50
  • Tank Capacity: 3.2 gallons
  • Remineralization: Yes

Overall the Home Master TMAFC-ERP Artesian RO system with permeate pump is a great RO system, but in our opinion it’s ideal for drinking water because it combines the powerful 7-stages filtration system with remineralization capabilities and a fast flow rate.

While there are other RO systems in the list with remineralization filters, this one adds calcium and magnesium twice during the purification process, which is great from your health and to improve the water taste, but also to prevent the degradation of the storage tank as acidic water may harm its rubber bladder.

The non-electric permeate pump of this RO system increases the flow rate to twice the average of a traditional RO system.

The pump also helps to reduce the waste water by increasing the pressure before the water enters the RO semi-permeable membrane, reducing TDS creep. The Home Master TMAFC-ERP system has a waste water ratio of 1:1, which is much better efficiency than the typical 1:3 of other similar systems.

A relevant factor is that this RO system has a 5-year limited warranty, which isn’t common on similar products.


  • Great water pressure
  • Great water taste
  • Good waste water efficiency
  • Remineralization
  • 5-year limited warranty


  • Price
  • Low GPD
  • Some customers complained about the installation process
  • Best for: Well Water
  • Filtering Stages: 7
  • Dimension: 15 x 8 x 18 inches
  • Weight: 20 pounds
  • Efficiency Ratio: 1 gallon filtered:3 gallons
  • Gallons per Day (GPD): 75
  • Tank Capacity: 3.2 gallons
  • Remineralization: Yes

The iSpring RCC7AK-UV Reverse Osmosis system is a great solution for water sources like well water or other unreliable sources, because not only is NSF and ANSI certified to deal with most of the water contaminants (like lead, arsenic, chlorine, fluoride, etc.) it also has a UV unit that kills any remaining microorganisms.

It also has an alkaline remineralization filter to restore back some of the good minerals that were removed from the filtered water during the RO process, which improves the water taste and makes it healthier for you and your family.

While it doesn’t remind you when you need to change the filters, it has a transparent see-through 1st stage housing that allows you to check the filter status.

The waste water efficiency ratio of the iSpring RCC7AK-UV system is 1:3, which is quite common compared to the typical RO systems, but is worse than other RO systems we mentioned in this guide.

The installation process should not be complex if you have some DIY skills and will take you around 1h, but we read some complaints about the quality of the installation instructions, and the recommendation is to use an online guide for more clear instructions.


  • Contamination removal capacity, with an UV sterilizer
  • Remineralization
  • Price
  • NSF certified
  • Good water taste


  • Low waste water efficiency
  • Some customers complained about the installation process not being easy
  • Best for: Efficiency
  • Filtering Stages: 7
  • Dimension: 18 x 17.6 x 15.6 inches
  • Weight: 28.9 pounds
  • Efficiency Ratio: 1.5 gallons filtered:1 gallon
  • Gallons per Day (GPD): 600
  • Tank Capacity: Tankless
  • Remineralization: Yes

The Frizzlife PD600-TAM3 Reverse Osmosis System is overall a great choice, but we would like to highlight its efficiency, as it only wastes 1 gallon for each 1.5 gallons of filtered water, much better than the conventional RO system. This system is more efficient, economical and environment-friendly than the rest!

Its tankless and compact design saves storage space under the sink, and it also has a high water output of 600 GDP, 8 times better than the 75 GPD of the traditional RO systems. This means that you can fill a glass of water in about 10 seconds, which is great if you have a large family.

The Frizzlife PD600-TAM3 system has some smart features that improve the user experience. It has an integrated digital TDS meter built in that allows you to monitor the water quality after the filtration process. It also has a color coded LED that reminds you to change the filters in advance.

Another important feature of this system is that it has an alkaline remineralization filter to add back the relevant minerals that are removed in the early stages of the RO process, raising the water pH to more than 7.5, which is beneficial for your health and improves the taste of the filtered water.


  • Great waste water efficiency
  • Tankless, with a great design
  • Remineralization & alkalinization
  • Smart filter life indicator
  • TDS water quality monitoring
  • Easy to install
  • Amazing capacity of 600 GPD


  • Price
  • Slow water flow
  • Some customers complained about leaking
  • Best for: Portable
  • Filtering Stages: 4
  • Dimension: 14 x 6 x 6.5 inches
  • Weight: 7 pounds
  • Gallons per Day (GPD): 90
  • Tank Capacity: Tankless
  • Remineralization: No

The APEC RO-CTOP Reverse Osmosis system is a great option if you need a portable device, because it’s a countertop system that connects directly to the faucet, doesn’t require a permanent installation and is really light compared with other alternatives.

All of this makes this system a perfect choice for apartments, condos, RVs, frequent travelers, students, and anyone that needs a portable and transportable RO system.

The APEC RO-CTOP system doesn’t require a permanent installation so there is no need to drill a hole in your countertop, you just need to connect it directly to the faucet and it will be ready to produce filtered water. Take into consideration that it only connects to standard kitchen faucets, so if you have a special faucet it may not work for your situation.

There is an option to add a case to cover the filters making it more convenient and discreet, but the tubes connected to the faucet will still be there.

It can produce 90 gallons of filtered water per day, more than the usual 75 GPD of a typical Reverse Osmosis system.

This version doesn’t remineralize the filtered water, so if you want the important minerals in your water, there is a version with an alkaline filter the APEC Water Systems RO-CTOP-PH RO System, that is similar to this one, just slightly heavier (9.55 pounds).


  • Portable
  • Lightweight
  • Easy installation, and not permanent
  • Good filtering capacity


  • Tubes showing isn’t aesthetically pleasing
  • Only works with standard kitchen faucets
  • Some customers complained about the time it takes to fill a glass of water
  • Best for: Apartments
  • Filtering Stages: 5
  • Dimension: 9.5 x 19 x 17 inches
  • Weight: 24 pounds
  • Efficiency Ratio: 1 gallon filtered:1 gallon
  • Gallons per Day (GPD): 75
  • Tank Capacity: 0.5 gallons
  • Remineralization: Yes

The RKIN U1 Countertop is a great RO system with powerful filtration capacity and a perfect choice for an apartment, condo, or RV due to the small space it requires.

The RKIN U1 Reverse Osmosis System is a high-quality water filtration system that provides clean, pure water for your home or office. With its advanced 5-stage filtration process, the U1 removes up to 99% of impurities and contaminants from your tap water, including lead, chlorine, arsenic, fluoride, and more.

One of the standout features of the RKIN U1 is its compact and sleek design, which makes it a great choice for those who have limited space under their sink. Despite its small size, the U1 is capable of producing up to 75 gallons of clean water per day, which is more than enough for most households.

Another great feature of the U1 is its high-efficiency ratio of 1:1. This means that for every gallon of water produced, only one gallon is wasted, making it one of the most water-efficient RO systems on the market. 

The RKIN U1 is also very easy to install and comes with all the necessary components and instructions to get up and running in no time. And with its long-lasting filters, you won’t have to worry about frequent filter replacements.

The RKIN U1 includes a remineralization stage in which a remineralization filter that adds back beneficial minerals such as calcium and magnesium to the purified water, improving its taste and providing health benefits.


  • Portable
  • Compact and sleek design
  • High-efficiency ratio of 1:1
  • Option to get hot or cold filtered water
  • Easy to install
  • Long-lasting filters
  • Includes remineralization filter


  • Price
  • Small water reservoir, so you may need to run multiple filter cycles in a day
  • Have to manually empty water tank to reuse

Buying Guide for a Reverse Osmosis System

Buying a Reverse Osmosis system for your home is not easy, because there are different factors to consider and several different options in the market. We put together all the relevant information to help you understand how to select the best RO system for you.

What to Look For in a Reverse Osmosis System

When researching for a Reverse Osmosis system to buy, there are a few factors that you should consider before making your decision:

Filtering Stages

Just one water filter won’t be able to remove all the different types of contaminants and impurities, so typically Reverse Osmosis systems combine multiple filters, each one representing a different stage in the filtration process.

More stages don’t necessarily mean that a RO system is better, but means that more filtering is done to the water to ensure its purity.

A 4-stage RO system is able to purify your water, but there are larger RO systems with more stages, which may include stages to add minerals lost in previous stages, or additional filtration stages to improve the water taste.

Waste Water

A major drawback of Reverse Osmosis systems is that they generate a lot of waste water in order to produce pure water because not all the water that goes through the system comes out as drinking water.

You will find out in the RO specifications that this feature measured as a ratio, i.e., a system that produces 75% of waste water will be represented as a 1:3 ratio (25%:75%), which means that to produce 1 gallon of filtered water, it produces 3 gallons of wastewater.

RO systems with a waste ratio worse than 1:3 are not a great choice, particularly if you need to filter a considerable amount of water.

The amount of waste water generated is linked to the pressure of the inflow water, higher pressure is better as a smaller amount of water is wasted. Some RO systems have pumps that will increase the pressure and help to reduce the waste water ratio.

One thing that you can do is to reuse the wasted water for other uses, like watering your lawn.

Water Output or Gallons Per Day (GPD)

Another important factor to consider is the amount of filtered water a RO system can generate in one day.

Take into consideration that the metrics mentioned in the RO specifications come from tests taken in standard conditions (water pressure of 60 psi and water temperature of 77 ºF or 25 ºC), which may differ from a real-life situation.

You can use our water use calculator to calculate how much water you need for drinking and cooking, and choose your RO system according to your family’s needs.

If you need more filtered water or if your home water pressure is too low (below 40 psi) a RO system with a booster pump might be a better choice for you.

Water Source

This is an important factor for most of the water filters because depending on where you live, the water that comes to your house might have different contaminants.

If you know which contaminants you need to deal with, then you can check if the RO system is able to remove them.

Some RO systems are better than others to filter the different contaminants that come from well water.

Tank Size

The reverse osmosis process is not fast, so most of the RO systems have a pressurized storage tank to store the filtered water to make sure you always have pure water when you need it, instead of having to wait for it to be filtered at the moment.

Before purchasing a RO system, you should consider your family’s drinking needs to ensure that the tank has the right capacity.

There are also some tankless Reverse Osmosis systems that don’t need a tank and produce pure water faster than usual, so it might be a good idea for you if you don’t have enough room for the storage tank.

Ease of Installation

Before buying a RO system, you should decide where it will go, and if you have enough room for it.

Another important thing is to check the top of your sink as most RO systems will require a separate faucet, which may not be easy to install.

When buying a RO system, you should consider if you will be able to install it by yourself or if you will need some external help. If the second scenario is most likely, then you add that potential cost to your budget.


Reverse Osmosis systems are great at removing contaminants, but in the process, they also remove minerals that are good to us, like calcium and magnesium.

Some RO systems have a re-mineralization filter to add back at the end of the process important minerals that were removed during the initial stage.

This is not essential because if you have a balanced diet, you will get magnesium and calcium from your food.

Replacement Filters

A Reverse Osmosis system has more than one filter, and they need to be replaced from time to time to ensure they are filtering properly.

While this is easier in a system with just one filter type, in a RO system you need to replace different filters, with distinct frequencies.

Usually, the semi-permeable membrane needs to be replaced every 2 years, while the sediment, carbon, and polishing filters should be replaced every year.

Benefits of Owning a Reverse Osmosis System

Having a Reverse Osmosis system is a great option for your house. You can check the main benefits below:

Removes Contaminants & Impurities from Your Water

One of the key benefits of an RO system is that it removes several contaminants, significantly improving the quality of the water that you drink.

A RO system can remove heavy metals, chlorine, bacteria, nitrates, arsenic, impurities, and much more.

Improve Water Taste & Odor

Another important benefit of a RO system is that it improves the taste and odor of your water, because some of the removed contaminants are responsible for the bad taste.

One of the most common reasons for the rotten egg taste of unfiltered water is the presence of hydrogen sulfide [1], which is removed by a Reverse Osmosis water filtration system.

Simple to Install

Typically, installing a Reverse Osmosis system is simple, and is something that you could do by yourself without the need of a plumbing expert.

Easy to Maintain

RO systems need some maintenance, specifically, the different filters need to be changed periodically.

But this is a simple task, as most of the RO systems are designed to be simple and easy to swap filters in a few steps.

Saves you Money

Buying a RO system will save you a lot of money, considering the other option you have to drink clean water, which is purchasing bottled water.

The price of a RO system is just a small fraction compared with the amount you spend to buy bottled water every year.

Environment Friendly by Removing Bottled Water Consumption

Another benefit of using a Reverse Osmosis system instead of bottled water is that it is an environmentally friendly option.

If you drink purified water instead of bottled water you are heavily reducing the amount of plastic waste that goes into our oceans.

What Is a Reverse Osmosis Water Filter System?

Reverse Osmosis is a process in which unfiltered water is pushed through a semi-permeable membrane that blocks contaminants and impurities. You can learn more about Reverse Osmosis in our article about it.

Reverse Osmosis Water Filter System is one of the most popular and effective methods to get high-quality drinkable water, as it is really effective in removing a diversity of impurities and contaminants [2].

How Does a Reverse Osmosis System Work

But a Reverse Osmosis system does not use only a semi-permeable membrane to remove contaminants, there are more components and processes in place.

Read below about the Reverse Osmosis’s different components, and how it works step-by-step.

Reverse Osmosis Components


In a RO system, before the water reaches the RO membrane, it passes through a set of filters to ensure that larger impurities are removed to avoid damaging the semi-permeable membrane.

RO Semi-Permeable Membrane

The semi-permeable membrane filters all the particles larger than 0.001 microns, removing up to 99% of water contaminants.

This component is the core of the Reverse Osmosis system, as this ultra-fine filter ensures that almost all the water that passes through it is pure.

Post Filters

Typically, the RO system has a post-filter step, in which the water passes through a carbon filter after leaving the pressurized tank and before reaching the final consumer. Some RO systems have additional filters as part of this post-filter component.

This is to ensure that any weird taste and/or odor is removed from the water before you drink it.

Shut-Off Valve

These are automatic valves that detect when the tank is full and shut off the system.

Flow Restrictor

A flow restrictor creates high pressure into the water and pushes it through the RO membrane, restricting the flow of RO rejected water.

Storage Tank

Usually, RO systems have pressurized storage tanks to store the purified water before being consumed. This is to avoid having to wait for the water to be purified only when you want to drink it.

Remineralization Filters

Not all the RO systems have this, but some will have an additional remineralization filter to add back to the purified water some important minerals, such as calcium, magnesium, or iron, that were removed in earlier steps of the RO process.


A RO system usually comes with a faucet that you should install in your sink to get the water filtered by this device.


Some RO systems have a booster pump that will increase the pressure inside the RO system, making sure it has good efficiency.

If your water pressure is low, you may want to consider installing a permeate pump to increase your RO system output and decrease the waste water generated, increasing its efficiency.

Some pumps can improve the waste water efficiency from 1:3 to 1:1, which is a huge saving in the long run.

Reverse Osmosis System Filtration Process Step by Step

Most of the Reverse Osmosis systems have 5 steps, but most recently some manufacturers added additional steps to improve even more the quality of purified water.

Let’s check the 7 steps (including the additional ones) of a RO System:

Step #1: Sediment Removal

The first filter, a sediment filter, removes larger particles (5-micron and above) and contaminants like sand, rust, or dirt.

Step #2: Carbon Filter

In this step, the water passes through a carbon filter that removes more harmful chemicals such as chlorine.

This not only purifies the water, but also improves its taste and odor, and most importantly, prevents harmful contaminants from reaching and damaging the RO membrane.

Multiple carbon filter cycles can be used in this step, some RO systems have more than one carbon filter.

Step #3: Reverse Osmosis

In the most important step of the process, the water passes through the semi-permeable RO membrane which has ultra-fine pores that block even the smallest particles, leaving only pure water to go through.

Step #4: Contaminants & Impurities Removal

The suspended contaminants & impurities in the water flow out of the RO system through a specific pipe, avoiding cross contamination.

Step #5: Polishing Carbon Filter

The filtered water passes through a final carbon filter before going directly to your faucet to ensure that bad smells and odors are eliminated from the water before you drink it.

This is the final step for many Reverse Osmosis systems, but some will have additional steps that we will cover now.

Step #6: Remineralization

In this additional step, some important minerals that were removed by the RO membrane are added back to filtered water.

This step will also improve the taste of your water, make it healthier with the addition of beneficial minerals, and make it less acidic.

Step #7: UV Filtering

Also an additional step, some RO systems use UV filters to remove microorganisms, bacteria, and viruses from the water, adding an additional layer of purification.

Contaminants Removed by Reverse Osmosis System

A Reverse Osmosis system is really effective at removing contaminants from your water, being able to remove up to 99% of contaminants and impurities, such as heavy metals, bacteria, pesticides, lead, nitrates, etc.

In the next chart you can find the maximum percentage of each contaminant that a Reverse Osmosis system is able to remove from your water.


Installation & Maintenance

Most of the Reverse Osmosis systems need an initial installation, but is typically quite simple and straightforward, and something that you can do by yourself.

You will only need to connect the RO tubes to the cold water and waste pipes from your home (usually under the sink), and install the filtered water faucet, which may require a drill in the counter if there isn’t one already.

Some of them do not even need installation, like a countertop RO system which you only need to connect to your faucet.

Most of the RO systems follow the same installation process, so let’s cover how to install a RO system step by step.

How to Install a Reverse Osmosis System in 10 Steps

Step #1: Turn off and Disconnect the Cold Water

Turn the shut-off valve to turn off the cold water, and disconnect the water feed pipe from the shut-off valve.

You can use a towel to clean some small amount of water that was still on the pipes.

Step #2: Connect the RO System to the Cold Water Line

Use the T connector that comes with the RO system to connect the cold water supply to the RO system.

Step #3: Connect the RO System to the Waste Line

In this step you need to drill a hole in your waste pipe, and attach the drain clamp.

Then, install the shut-off valve if your RO system has one.

To minimize the noise generated by the system when the water is flushed down the drain, we recommend drilling the hole in the horizontal section of the waste pipe.

Step #4: Install the Faucet

If you need to install a faucet, this is the time to do it. If your sink does not have a pre-drilled hole, you will need to drill a hole on it.

This is probably the most complicated step, so make sure you take the necessary precautions like using the right tools and wearing safety glasses.

After drilling the hole in your sink, place the faucet in it and align it in the right direction, and connect the tubes at the bottom of it.

Step #5: Install The Filters

Then, mount the filters on the side or back wall of the cupboard, taking into consideration that you need to leave some space to be able to change the filters from time to time.

Step #6: Install The Water Tank

Install the water tank on the cupboard, making sure you place in on a flat and leveled surface.

Step #7: Connect The Water Pipes

Connect the water pipes using the color-coded connectors, making sure everything is correctly connected.

Step #8: (Optional) Plug The System

If your RO system has a UV filter, you need to connect it to an electrical outlet.

Step #9: Turn the Water Back On

Is now time to turn the water on to check if there are any leaks in the system that you just installed.

Step #10: Test the System by Filling and Emptying the Water Tank

Finally, you need to test if the system is working properly.

Fill and empty the water tank a few times (check your RO system manual for recommendations) to ensure that all the components are working and that no leaks exist.

Reverse Osmosis Maintenance & Filter Change

If you are looking to buy a RO system, you should understand how difficult it is to maintain it.

For all the RO systems we cover, the filter change is easy and really straightforward, so you should just need a few minutes a year to change them.

Typically, you will need to replace the pre (sediment and carbon) and post (carbon) filters every 6 to 12 months, but this will depend on the usage and level of impurities of your water source.

The RO membranes have a longer lifespan and should be replaced between 2 to 4 years, depending on the model, water usage, and water source contaminants.

Some RO models have LED lights to let you know when your filters need to be replaced.

But you should clean the RO membranes every 3 to 12 months, depending on the usage. You can do it by yourself or use an expert company.

Apart from this, no more maintenance is required for a Reverse Osmosis system.

FAQ About Reverse Osmosis System

Here are some answers to frequently asked questions about Reverse Osmosis systems

How much does a Reverse Osmosis system cost, and what are the expected recurring costs?

A good Reverse Osmosis system should cost you between $200 and $500. If you need to hire a plumber to install the system, you can add an additional cost between $100 and $200.

Regarding expected recurring costs, they are basically associated with the replacement of the filters. That should cost you between $30 and $50 a year.

How long does a Reverse Osmosis system last?

If you buy a good quality Reverse Osmosis system and maintain it properly, i.e., cleaning and replacing the filters with the required frequency, it can last almost forever.

Worst case scenario you might have to replace parts of the system, but not the whole system.

Does the Reverse Osmosis system have an impact on the environment?

RO systems generate waste water, which is not good for the environment. But the positive side is that if you drink filtered water from a RO system, you will reduce the consumption of bottled water, which has a worse impact on the environment.

You can also minimize the negative impact of waste water if you try to reuse it for other purposes, such as watering your plants and lawn.

Which one is better, distilled water or RO water?

While both are good options as the filtration processes associated with them are really powerful, the distilled water may still have some pesticides and herbicides, making RO a better option.

Does the Reverse Osmosis system remove minerals from the water?

Yes, RO systems remove almost all the minerals of the water.

Does the Reverse Osmosis system remove fluoride and chlorine?

Yes, RO systems remove fluoride and chlorine from the water.

What is the difference between a single pass and a double pass Reverse Osmosis system?

The main difference between a single and double pass RO system is that in a single pass the filtration process is done once, and in a double pass is done twice.

In a double pass RO system, the pure water generated after the first pass is used as feed water for the second pass, making the water go twice through the system, increasing the quality of the resulting water.

What is the difference between a One-Stage and a Two-Stage Reverse Osmosis system?

In a one-stage RO system, the feed water that enters the system leaves it part as waste water (or concentrate) and part as pure water (or permeate).

In a two-stage RO system, the waste water is used as feed water for a second stage, increasing the recovery of the RO system. In this type of system, the permeate water from both stages is combined and used as pure water.

Do I need a permeate pump?

If you have good water pressure at home you might not need one, but if you use one, you will increase your RO system performance reducing the amount of waste water generated.

Do I really need a remineralization filter?

RO systems remove minerals, which can cause a different taste than usual for some people. If this taste seems weird to you, then you probably need a RO system with a remineralization filter.

Does a Reverse Osmosis system require electricity to work underneath my sink area?

Not really, as RO systems typically work just with water pressure.

That being said, some RO systems may have electrical permeate pumps to increase efficiency, so you might consider this need if you want one of these systems.

Our Verdict

A Reverse Osmosis system is a great choice if you want to drink pure and healthy water, as its multi-stage filtration process ensures that the majority of the common water contaminants are removed from the water.

So if you are looking for the best Reverse Osmosis system, our recommendation is the Waterdrop G3P800 as the best overall RO choice.

This system delivers great amounts of purified water in an efficient manner, has some nice monitoring features, and its tankless and modern design saves you space undersink and makes the installation process easier.