Reverse osmosis systems, also known as RO systems, are the key to protecting your water from harmful contaminants. You might have one in your house but older models tend to be bigger, less space efficient, expensive to own and maintain. Fortunately, the newer reverse osmosis water filtration systems allows you to install with ease and without breaking your bank.
It is likely that you’re on this page because you want cleaner, safer and healthier drinking water for you and your loved ones or you just want to study more about water filtration systems. Well, you’ve come to the right place.
Keep on reading to find out more about what a reverse osmosis system is and what you need to look out for when searching for the best reverse osmosis system for your house. Additionally, we’ve also prepared a guide for you to install and maintain an RO system on your own.
What is a Reverse Osmosis System?
A reverse osmosis, or sometimes known as RO, is a careful process where you can remove impurities from your water by flowing through a permeable membrane. Reverse osmosis is the opposite of osmosis and in the process of osmosis, purer water flows towards water that is less pure. On the other hand, reverse osmosis utilizes pressure to force less pure water through the membrane so impurities are removed and you get purer water.
In order for the RO system to work perfectly and effectively, it will usually go through a series of stages and let’s have a look at the stages in an RO system. After that, we will also be taking a look at what are the components that make up an RO system.
Stages of Reverse Osmosis Water Systems
Normally, an RO system will consist of six stages in the system but there are some reverse osmosis systems that don’t necessarily have six stages. Here are the six stages:
- First stage – The first of six stages of an RO system is also known as the sediment removal stage. Before the water goes through the semi-permeable membrane, the sediment filter will remove rough particles, rust, sand and dirt from the water.
- Second stage – The second stage is also the first carbon filter stage. This stage is to remove harmful chemicals such as chlorine to prevent damaging the reverse osmosis membrane. It will also help to improve the taste and odor of the water, get rid of some pesticides and tinier particles that went through the first stage with the water. Some RO systems have a second carbon filter stage for better efficiency and to ensure more particles are removed. Several carbon cycles might be needed based on the contact time and the quality of the carbon.
- Third stage – This is the stage where reverse osmosis takes place, removing the dissolved solids and whatever that’s larger than a water molecule with a reverse osmosis membrane. RO membranes consist of many small holes, allowing water molecules to go through under pressure, but not anything bigger.
- Fourth stage – The fourth stage is known as the remineralization stage. Remineralization is as the name suggests, which is to remineralize the water with healthy minerals such as calcium and magnesium. It also balances the acidity of the water since purified water is slightly acidic and the good minerals were removed during purification. This part of the reverse osmosis process gives a healthier and better taste of the water.
- Fifth stage (optional stage or stages) – This is the stage where some RO systems differ from one another. Some add UV light filters to eliminate microorganisms while some have deionization/nitrate/arsenic/fluoride filters that get rid of hazardous contaminants remaining in the purified water.
- Sixth stage – The sixth stage is also known as the final carbon stage and this stage has a filter that acts as a “polishing” filter. The purpose of this filter is to remove any accumulated tastes or smell from the water.
Components that Make Up a Reverse Osmosis Water Filter
For a reverse osmosis system to work, there are several components that support it. These components are also the keys to differentiating the quality of a reverse osmosis water filter system.
Pre-filters are necessary for every RO system. The purpose of pre-filters is to filter out large grains of sediments such as dirt or sand from the water because these sediments could hinder the functions of other parts of the system.
This is without question the most important part of the RO system. The function of this membrane is to trap harmful contaminants including pesticides that you don’t want in the unfiltered water.
Post filtering is the process that happens after the water exits the pressurized tank and before reaching your taps. The post filter treats the water one last time to remove the remaining carbon and give the water a better taste and smell.
This is the component that ensures the system works efficiently. Shut-off valves are typically automatic and it shuts off the system when the water tank is full.
How fast an RO filter can feed water through the filters will have an effect on the volume of purified water going into the storage tank after filtration. The flow restrictor is used to increase water pressure and push the water through the RO membrane.
Normally, reverse osmosis systems store purified water prior to using in their own storage tanks and different tank designs hold different volumes of water.
Since RO filters eliminate all the particles from the water, minerals are removed as well. There is no doubt that these minerals can be obtained from our food but it’s a lot more convenient getting it from our water and this is where remineralization is needed. Remineralization filters allow minerals to be added to the filtered water before the water reaches the storage tank.
The standard faucet in your kitchen will need to be changed to an air gap faucet if you are getting a reverse osmosis system fitted and it will usually come with your system. An air gap faucet provides a gap for the drain to prevent water from the system’s drain flowing back into the system.
In RO systems, there are usually two types of pumps, electric and permeate pumps. An electric pump utilizes a pressure switch to supervise the water pressure in the storage tank and turns on a pump when pressure needs to be increased. However, not all systems will need an electric booster pump, only if water pressure drops below 40 PSI and want better efficiency and less waste.
On the other hand, a permeate pump is used to enhance the system efficiency of water production. Without a permeate pump, water will be wasted and efficiency lowered. Having a permeate pump will avoid up to 80% of wastewater. The permeate pump holds the impure water in a chamber and utilizes it to produce energy, speeding up the water production during the RO process.
Buying Guide for the Best Reverse Osmosis Water Filters
In order to find the best reverse osmosis system for your home, there are some considerations that you need to think about. Here are some of the considerations that will help you best.
The first thing to consider before buying any reverse osmosis systems is the source of your water. Different sources of water can affect the RO process, depending on the contaminants the water contains. Normally, if there are more contaminants in the water, it will be harder for the RO membrane to effectively filter out the contaminants.
In comparison with non-RO filters, an RO filtration system will have a better flow. However, the reported rates for the filters are the maximum under perfect conditions and since flow can be affected by many other things, the design of the filter itself is not enough to justify the system’s flow. Flow also differs depending on water quality so it is difficult to gauge an exact flow of filters.
The capacity is referring to the number of gallons an RO filter is able to produce daily, or sometimes known as gallons per day (GPD). Some filters come with a high-capacity tank that stores as much as 75 gallons of filtered water. However, a larger tank isn’t always required because the system refills at a constant rate too.
Generally, the water consumption per day for most families is 3 gallons or less for cooking and drinking. Based on this statistic, you can estimate the capacity you need according to the number of people in your house. For example, if there are 5 family members, 15 gallons will be enough.
Consuming healthy minerals is good for your health and it is great to get it from your drinking water. However, reverse osmosis systems remove minerals and you’ll need to remineralize your water to get the beneficial minerals back. By adding an additional filter, you’ll be able to get these good minerals back.
Type of Membrane
Generally, there are two types of membranes, Cellulose Triacetate (CTA) membranes and Thin Film Composite (TFC) membranes. CTA membranes are a result of paper by-products bonded to a synthetic layer and some chlorine in the water is required to avoid bacterial growth.
TFC membranes are fully-synthetic and any traces of chlorine will damage it. Systems that are using TFC membranes utilize carbon pre-filters to get rid of the chlorine before the water reaches the RO membrane. TFC is also recommended because it eliminates more contaminants.
Installation & Maintenance of Reverse Osmosis Systems
Traditional water filter systems can be quite complex which is why it was difficult to install and maintain them. However, the modern reverse osmosis water filters are made to be easy to install and maintain by most people. Keep on reading to find out how you can install and maintain RO systems on your own.
- Turn off the cold water valve. Before installing, make sure you turn off the cold water valve so there won’t be any water during the installation. Usually, you will find the valve under the sink and connected to copper piping.
- Connect the system to the cold water line. You will be given an adapter when you purchase the system and connect it to the line to give the feed water to your system. But before you do that, make sure the cold faucet is “on” to relieve any line pressure.
- Set up the drain line. At this step, you should check for any corrosion first and make sure to replace it before you continue with the installation. If all is good, then you may proceed. You will need to drill a hole into the existing pipe and attach the drain clamp. Make sure you tighten the clamp but don’t tighten it too hard. A shut-off valve will also be installed in this step if the system has one.
- Installation of the faucet. You can drill a hole or use the existing one to accommodate the new water faucet. If you are drilling a hole, make sure it’s as close to the previous one as possible and drill with proper tools and safety equipment. Tighten the faucet and align it in the direction of use then attach any necessary tubing to it.
- Place the unit. The final step of the installation is to put the unit at the location you want and connect the reservoir tank to the filter system. After this, you’ll be able to enjoy healthy and clean water.
- Turn off all the valves. This includes the cold water valve and the one at the reservoir water tank.
- Open faucet. Drain out all the water and relieve the pressure.
- Unscrew filter. Use a filter wrench to unscrew it from the housing.
- Replace filter. Discard the used filter and insert the new one.
- Tighten filter. You may hand tighten the filter and finish off with the wrench. Make sure it’s not too tight so you can still unscrew it for the next maintenance.
- Repeat for additional filters. Repeat steps 3 to 5 for each extra filter that needs replacement.
- Check for leaks. Lastly, open the faucet and let it run for 1 to 2 minutes and check for any leaks. If any leaks are discovered, just tighten the filter more.
Best Rated Reverse Osmosis Water Filter Systems in 2021
Now that you have a better understanding of reverse osmosis filtration systems, let’s have a look at the list of 8 best reverse osmosis systems on the market.
1. Waterdrop WD-G3-W
- 400 GPD
- Dimensions: 18.06” x 5.68” x 17.76”
- Tankless design
- Smart monitoring panel
- NSF 58 & 372 certified
The Waterdrop WD-G3-W is the best tankless reverse osmosis water filtration system on the market. This is an extremely powerful RO water filter, producing up to 400 gallons of water per day. For a clear comparison, the typical reverse osmosis filters only produce about 75 gallons daily. Plus, the traditional ones have a tank which takes up more space.
The reason that the Waterdrop WD-G3-W Reverse Osmosis Filtration System doesn’t have a storage tank is that it filters water on demand. As a result, it doesn’t have to slow down to refill and can keep producing because it only needs 12 seconds to filter a cup of water. Thanks to its design, this unit is extremely easy to install.
With a water to waste ratio of 1:1, it ensures that the system is efficient and won’t waste water as much as standard RO systems. The Waterdrop WD-G3-W has three filters to provide seven stages of filtration. It has a sediment pre-filter, an RO filter and a final carbon filter producing water that is free from TDS, fluoride and other contaminants.
Has a high volume output. The output is measured at 400-gallon which is higher than most RO systems on the market.
Ease of installation. Thanks to a tankless design, this reverse osmosis filtering system have an easy installation that doesn’t take much effort.
NSF 58 and 372 certified for safe water. It is certified against NSF 58 for TDS reduction and NSF 372 for lead-free material so you know you are consuming safe water.
Sleek design. Because this is a tankless reverse osmosis water filter, it has a sleek and compact design.
Higher price than its competitors. Since it’s more powerful than its competitors, it is no surprise that it’s also more expensive.
Slow water flow. The rate isn’t the best and could be faster.
2. Home Master TMHP HydroPerfection
- 75 GPD
- Dimensions: 15” x 15” x 5”
- UV filter
- Patented full contact technology
- Permeate pump
Introducing an incredible RO system, Home Master TMHP HydroPerfection. This is an under sink reverse osmosis system that ensures you and your family can enjoy the cleanest possible water. It has 9 stages of filtration to make sure that the water supply you get is as clean as possible.
With the permeate pump that the Home Master TMHP HydroPerfection is equipped with, it produces an impressive output of 75 GPD. Thanks to the permeate pump, the system is able to achieve an efficient waste water ratio of 1:1 as opposed to the typical RO systems that have a ratio of 4:1.
This reverse osmosis filter comes with a UV light filter that eliminates up to 99.8% of microorganisms, ensuring your water is free from contaminants. It is also highly recommended to get this filter especially if you are using well water supply.
One more thing that many homeowners will appreciate is the durability of the filters. The filters last for a long time and you only need to change filters after 2000 gallons.
Long lasting filters. The filters only need to be changed after 2000 gallons which is incredibly durable.
Thorough filtration process. Besides the UV light, it also has a nine-stage filtration to ensure you’re getting the purest water.
Has a permeate pump. This ensures that the system has minimal water waste.
Bulky size. The Home Master TMHP HydroPerfection has many filters and because of that, it has a bulkier size and homeowners might encounter a difficult installation in small kitchens.
Higher price tag. With the advanced technology that it’s equipped with, the price of this system is also higher than some of its rivals.
3. NU Aqua Platinum Series 5
- 100 GPD
- Dimensions: 16.9” x 16.5” x 16.3”
- HydraCoil technology
- Double O-ring sealed filter housings
- Free installation of DVD and PPM meter
The NU Aqua Platinum Series 5 Stage Reverse Osmosis System is one of the cheapest systems on the market that offers clean and good tasting water. It can also ensure a high efficiency operation thanks to the booster pump.
The flow rate of this 5 stage system is also one of the highest on the market, measured at 100 gallons per day and the output speed is close to double of standard systems. However, the water waste ratio is slightly high compared to some systems in the list. At a ratio of 1:2, every 1 gallon of purified water will result in 2 gallons of wastewater.
For those that prefer to test the water quality, the NU Aqua Platinum Series is equipped with a PPM meter for quality testing purposes. Besides that, if water pressure is lower than the recommended 60 PSI, you can add an additional pump to the system.
Budget-friendly. The price of this reverse osmosis water filter is cheaper than most of its rivals.
Able to check the quality of water. With a built-in PPM meter, you can easily check the quality of your water.
High capacity filters. The filters are able to provide an output of 100 GPD which is more than enough even for large families.
Doesn’t include a filter for remineralization. Unlike some of its competitors, this RO water system doesn’t have a filter for remineralization.
4. iSpring Deluxe Under Sink 7-Stage Reverse Osmosis System
- 75 GPD
- Dimensions: 15” x 8” x 18”
- Alkaline Remineralization (AK) filter
- Flow Sensor
- UV filter
The highly-rated and popular RO system, iSpring RCC7AK, is one of the best systems for you to get clean water. Thanks to the UV light filtration, the iSpring system can remove up to 99-percent of undesirable contaminants, keeping your water free from harm.
The iSpring alkaline remineralization filter also adds back sodium, calcium, magnesium and potassium that was removed from the water by the RO membrane. Plus, iSpring has 7 stages of filtration so you’ll be getting pure drinking water.
Has a filter for remineralization. The AK filter adds on the elements that were taken out during the reverse osmosis process.
Easy DIY installation. Installation can be done easily on your own or with some help from your family members.
Decent capacity. The volume per day is more than enough even for large families.
Short warranty period. The iSpring system only offers a one-year warranty period.
System efficiency is slightly low. For every 1 gallon of water produced, 3 gallons are wasted.
5. APEC Water Systems Ultimate Series RO-90
- 90 GPD
- Dimensions: 16” x 5.25” x 17.5”
- WQA Gold Seal Certified
- Extra large carbon block
- Super capacity filters
Another impressive reverse osmosis system, APEC Water Systems Ultimate Series RO-90, is the perfect option for anyone looking for incredible water flow rate and clean drinking water. APEC equipped this with a super capacity sediment filter, two carbon blocks, RO membrane and refining coconut carbon filtering cartridge. Giving it 5 stages of optimal filtration.
This APEC Ultimate Series RO-90 also received certification to prove that it removes up to 99-percent of contaminants. The removed contaminants include chlorine, lead, arsenic and many more.
Cheap to own and maintain. The cost of APEC Ultimate Series RO-90 is quite low and the maintenance is relatively cheap too.
Ease of installation. The parts are color-coded for easy assembly.
Good customer support and warranty. They provide great customer service and a 2-year warranty to back up their products.
Can’t remineralize your water. No filters included for that purpose.
6. Express Water Reverse Osmosis Alkaline Water Filtration System
- 50 GPD
- Dimensions: 19” x 18” x 16”
- Active Mineral Technology
- Customizable RO water filter
- 4 gallons storage tank
This reverse osmosis water filtration system, Express Water, is a product that gives you clean and healthy alkaline water. The 10-stage filtration ensures that 99-percent of contaminants and pollutants like lead, chlorine, arsenic and bacteria are thoroughly removed.
Setting up this reverse osmosis water filtration system is also extremely easy thanks to its simple design. Output is great for medium to large families and the filters last for surprisingly long at the price you are paying.
Long lasting filters. The longevity of the reverse osmosis filters are surprisingly high for the low price you’re paying.
Leak detection. Shuts off the water if a potential leak is discovered.
Customizable reverse osmosis water filters. You are allowed to choose from a different variety of reverse osmosis filters.
Assembly might be difficult for some people. Although the design is simple, some customers find it difficult to assemble on their own.
7. AquaTru RO Water System
- ¾ gallons every 12 minutes
- Dimensions: 14” x 14” x 12”
- Patented Ultra Reverse Osmosis Technology
- Digital display
- One-touch water dispensing
The AquaTru reverse osmosis water filter system is a compact unit meant to be placed on a countertop. It is easily one of the best countertop reverse osmosis filtration systems on the market.
Featuring a four-stage reverse osmosis water filtration, you are guaranteed to get pure water that is free from contaminants. This filter system is also 4 times more efficient than typical filter systems. With an impressive output of ¾ gallons every 12 minutes, it is perfect for families of all sizes.
Great efficiency. This system has an efficiency that is 4 times better than the standard ones so that it doesn’t waste water.
Compact and portable. Unlike the typical under sink reverse osmosis system, this is a countertop unit that can be moved around easily.
Small holding tank. Only has a one gallon tank.
8. Brondell Circle RO System
- 100 GPD
- Dimensions: 9.25” x 16.5” x 13.75”
- Patented water saving technology
- Unique circular reservoir design
- Under sink installation
The Brondell Circle Reverse Osmosis System is one of the most modern looking under sink reverse osmosis filter systems that you can get. You can also easily fit it under your kitchen sink thanks to its compact size. With their patented water saving technology, this system has incredible efficiency. For every gallon of purified water, only 2.1 gallons of water goes to waste.
This system is not only a breeze to install, but the maintenance is also extremely easy as well. The recommended time to change the filters is once every six months or a year. At 100 gallons per day, you will definitely have enough water regardless of your family size.
Sleek design. This RO water filtration system has a compact and unique design that can easily fit under a sink.
High output. This system can produce 100 gallons per day which is more than enough for any families.
Can’t remineralize. Your drinking water can’t be remineralized because it doesn’t contain the filter for that purpose.
What does TDS mean?
TDS stands for Total Dissolved Solids. TDS or total dissolved solids is the number of dissolved ions, which include harmful and good substances in your water.
What is the difference between a single pass and double pass RO system?
RO systems that are single pass filter water through a single RO membrane only and are commonly used for residential purposes, while double pass systems are for medical and industrial uses.
Do I need electricity work under my sink area?
No. RO systems work by water pressure and do not require electricity.