How to Select the Best Reverse Osmosis System for Home Installation

In Purification by Jeremiah CasteloLeave a Comment

Reverse osmosis has become one of the most efficient methods of purifying water since its discovery in the 20th century .

It uses the science of osmosis by forcing highly concentrated water  through a semipermeable membrane to a region of low solute concentration, essentially filtering out impurities on a molecular level.

Reverse osmosis (RO) is very effective in the treatment of brackish, surface and ground water. Many industries use water treated with RO systems including pharmaceutical, food and beverage, agriculture, dairy, metal finishing, and semiconductor manufacturing.

RO systems can also be used domestically to produce safe, healthy drinking water for you and your family.

In this article, we'll cover:

  • The science behind Reverse Osmosis - stages and components of an RO system
  • The benefits of using an RO system and things to consider when purchasing one
  • How to install and care for your RO system
  • What is the best reverse osmosis system for home use and where can I purchase one?

Our Top Pick for Best Reverse Osmosis Systems for Home Use

Clean, Efficient, Reliable

  • 4 Stages
  • 40 - 120 psi

The Circle by Brondell features a clean, space-saving design without any filters or tubing exposed. With their patented water-saving technology, the Circle is one of the most water-efficient RO systems on the market. Read our full review at the end of the article.

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How Does Reverse Osmosis Work?


Osmosis is the process of equalizing the concentration of particles in water by utilizing a permeable protein membrane. When water passes through the membrane, the concentration of dissolved particles on either side of the membrane become equal. While the protein membrane allows water molecules to pass through, it prevents larger molecules like minerals, salts and bacteria from diffusing through the membrane. Hence, an equilibrium is reached as the water molecules naturally flows from the area with high water potential to the area with a low water potential until the concentration is equal on both sides.

In contrast, reverse osmosis involves applying external pressure to reverse the natural flow of water and prevent an equilibrium from being formed. Through reverse osmosis, pressure is applied so that concentrated water is forced through the membrane allowing particle-free water to emerge on the other side.

  • (A) Applied Pressure
  • (B) Concentrated Water
  • (C) Dissolved Particles
  • (D) Membrane
  • (E) Clean Water
  • (F) Osmotic Pressure

Stages of Reverse Osmosis

A reverse osmosis system usually consists of three phases – pretreatment, reverse osmosis and post treatment. Some RO systems may include additional stages which are optional. As water travels through each stage, a different type of treatment process is applied before the water is ready to come out of the faucet for consumption. We'll explain the purpose of each stage in this section:

  1. Sediment Filter - The dirty or contaminated water is first pre-filtered with a sediment filter to remove larger trapped particles, including rust and calcium carbonate. Sediments and other particulate matter like dirt, silt and rust affect the taste and appearance of water. The sediment filter also acts to protect the filters that come after it by removing contaminants that could affect them. Because this filter is the first to come in contact with the water, it requires the most frequent replacement and should be done so every 6 months with regular use.
  1. Carbon Filter with Activated Carbon - The water is pre-filtered with a carbon filter. The activated carbon filters out chlorine, oils and trapped organic chemicals which can attack and degrade the thin film composite membrane used for the reverse osmosis filter. The oils can plug the reverse osmosis membrane and chlorine can eat the pores on the membrane, thus increasing the flow rate and allowing more contaminants to pass through as the pores on the membrane become larger. This filter should be replaced every year with regular use.
  1. Reverse Osmosis Membrane - This is where reverse osmosis takes place, removing most contaminants. The reverse osmosis membrane removes organic and inorganic compounds including fluoride, arsenic, lead, parasitic cysts and copper. It also greatly reduces impurities known as Total Dissolved Solids (TDS) which comprise inorganic salts such as calcium, magnesium and sodium.
  1. Remineralizing Filter - As water purified by reverse osmosis is highly pure and slightly acidic, a remineralizing filter is used to introduce healthy minerals, mainly calcium and magnesium, which also balances the pH and improves the taste.
  1. Storage Tank - This is where the water is stored after it has gone through the major stages of the purification process. In most systems, it is ready to be released through the faucet. Other systems might include additional stages.
  1. UV Filter (Optional) - The UV filter protects against biological contaminants by destroying microorganisms including harmful bacteria, E. coli, viruses, fungi and microbes. The UV rays penetrate harmful pathogens, destroying illness-causing microorganisms by attacking their genetic core (DNA).
  1. Color Changing Resin Deionization Filter (Optional) - The Color Changing Resin Deionization Filter removes all the remaining Total Dissolved Solids (TDS) from the membrane filtered water. There is usually a small amount of TDS left in the water after being filtered by the reverse osmosis membrane. This stage is required when the water is to be used in aquariums as lowering TDS for all aquatic animals is very important for osmotic regulation and hydration.
  1. Final Carbon Filter - The final carbon filter, also known as a “polishing” filter, removes any tastes and odors the water may have picked up from the storage tank. The slightly acidic water resulting from the reverse osmosis stage may dissolve some rubber in the storage tank which the final carbon filter removes.

What Contaminants are Removed?

Reverse osmosis removes a variety of contaminants. Reverse osmosis has the capability to remove up to 99%+ of the dissolved salts or ions, particles, organics, bacteria and pyrogens from untreated water. However, reverse osmosis is not efficient enough to remove 100% of bacteria and viruses, so UV filters may be used with RO systems.

The following tables gives a summary of some inorganic salts removed along with their percentages.


Percentage Removed


85 - 94%


96 - 98%


94 - 98%


85 - 95%


60 - 75%


94 - 98%


95 - 98%


95 - 98%


94 - 96%


96 - 98%


95 - 98%


92 - 96%


94 - 98%


96 - 98%


85 - 92%


94 - 98%


95 - 98%


95 - 98%


84 - 92%


85 - 92%

Basic Components of an RO System

RO systems consist of five basic components:

  1. Pressure Vessels and Membranes - Membranes are the fundamental parts of RO systems. Various proteins make up the membrane elements depending on the kind of water that is input and how clear the untreated water is. There are different membrane elements for brackish water, seawater, hospital-grade infection, and specific contaminants. The size and number of membranes required in a reverse osmosis system will depend on the size of the task – whether municipal, commercial or industrial.

  1. Reverse Osmosis Skid - Reverse osmosis skids are used to make RO systems durable. These skids are a powder coated, carbon steel frame used to mount all the components on. It is designed and built to withstand the heavy vibration of high-pressure pumps.

  1. Cartridge Filter - Cartridge filters are used to pre-filter the water and remove particles that are large enough to damage the membranes. A five-micron spun polypropylene filter is usually used as the cartridge filter, but it can vary upon request. The cartridge comes in a durable casing to handle pressure from the main feed and booster pumps.

  1. Reverse Osmosis High Pressure Pump - High pressure pumps are crucial for the rejection rates of RO systems. High-grade pumps are essential for a feasible rejection rate in commercial and industrial settings. The high-pressure pump needs to be matched to the membrane size and quantity as well. In general, the higher the horsepower of the pump, the higher the rejection rates of the reverse osmosis membrane.

  1. Control Panel - A control panel is needed for the human operator to control the reverse osmosis system. Advanced PLCs or solid-state microprocessors are used depending on how advanced the controls need to be. In an industrial setting, a control panel can be used to control and manage multiple RO systems simultaneously.

In addition to these five basic components, other components can be built onto or into RO systems based on your requirements.

Benefits of RO System as Compared to Regular Filtration Systems


RO systems provide clean, refreshing water and they have many benefits over regular filtration systems.

  1. Removes all types of contaminants - RO systems are 99% efficient in removing all types of contaminants to produce clean and safe drinking water. The semi-permeable membrane isolates contaminants from water including bacteria, viruses, dirt, ions and heavy metals.

  1. Removes odor from water - While regular filtration systems do not remove odor from water, RO systems have a carbon filter with activated carbon that attracts and filters out odor-causing contaminants such as chlorine and iodine.

  1. Very easy to maintain - While you are required to wash and rinse regular filtration systems often, the filters in RO systems are washed regularly by the system itself. The concept of reverse osmosis makes the system easy for households to maintain and keep running for a long time.

  1. Long lasting and economical - RO systems generally last longer than regular filtration systems. As the membranes are washed by the rinse water itself, RO systems can last for a couple of years. RO systems are also very economical as they require minimal maintenance unlike regular filtration systems that require regular maintenance.

  1. Uses UV radiation - UV radiation is known to be the most effective method for disinfecting bacteria from water. While regular filtration systems do not use UV lamps, RO systems may use UV lamps to kill bacteria and viruses.

  1. Removes inorganic molecules - Although regular filtration systems with carbon cartridges are unable to remove inorganic compounds, RO systems can filter out inorganic molecules with the membrane. Inorganic molecules such as inorganic phosphorus, inorganic carbon and inorganic nitrogen found in brackish water can result in the formation of hard water.

Inorganic chemical contaminants such as bleach and curing agents may also be present in the source water meant for domestic consumption.

Things to Consider when Purchasing an RO System


RO systems are effective at purifying water, but they vary in efficiency. While some systems work well with well water, others do not. Here are some things to consider when purchasing a reverse osmosis system.

The Water Source

There are generally two main types of source water – city water and well water source.

In urban areas, the water source comes from a water treatment plant, so the water will contain less contamination. Thus, an entry level of reverse osmosis water filter systems is sufficient for homes in urban areas.

In sub-urban areas, private wells are usually the main water source, so the water is not treated beforehand and there is a relatively high concentration of contaminants – including living microorganisms, virus and bacteria. To eliminate these contaminants, you will require a reverse osmosis system with a UV light sterilizer.

Required Stages of Filtration

RO systems typically have 3, 4 or 5 stages of filtration. Systems with 4 stages of filtration are usually recommended for most applications. However, if you live in a sub-urban area with well as your main water source, the water will have high levels of sediment to a 5-stage reverse osmosis system is recommended which provides an additional pre-filtration to remove the sediments.

Water Pressure

Sufficient water pressure is required to push the source water through the membrane to filter out the contaminants. While most urban houses meet the minimum water pressure requirement of 40 PSI (pounds per square inch), if the source water pressure is less, you will need a system that comes with a booster pump. Some systems consisting of a booster pump are suitable for city water while some are suitable for well water instead.

The Quality of Filtration

RO systems have different rejection ratios due to technology differences. The pre-filters and post filters may help determine the effectiveness of the entire system. Most companies claim that their systems can remove up to 99% of all contaminants. The effectiveness can be gauged using a total dissolved solid (TDS) meter. You can also check to see if the reverse osmosis system is certified by a notified body. WQA and NFS are nonprofit notified bodies based in US that test and certify RO systems.

How much water is needed

The flow rate of the system will determine how much water you can get on average. The flow rate depends on many factors including the water pressure and the water temperature. Keep in mind that the actual production rate (GPD - gallons per day) may be 60% to 80% of the system GPD rating as ideal optimum conditions are hard to meet. A 50 GPD-rated system will be adequate for a common household, but a huge family of 8 will require a system with twice the GDP rating at 90-100GPD.

Your Budget

There are two types of cost you should consider – the initial cost and the maintenance cost. The initial cost is the initial purchase price of the system whereas the maintenance cost involves replacement of filters and faulty parts. Hence, if frequent replacement of filters is required, the maintenance cost will also be higher.

How to Install an RO System


The installation process of RO systems is simple and can be done with little help.

Find the best location

RO systems are generally made to fit under the sink. You should choose a location that is convenient to operate. Keep in mind that the cold-water valve should be shut during the installation as the system has to be installed along the cold-water line.

Faucet Installation

You can easily mount your faucet if your sink has extra holes for faucets. If your sink does not have an extra hole, you will have to drill a hole. Be mindful of the material your sink is made from when drilling – whether stainless steel or porcelain. If the hole is covered by a chrome plate, simply remove the chrome plate and mount the faucet.

For convenience, the faucet spout should be allowed to move freely. Follow these steps to install the faucet.

  1. Insert the faucet stem into the hole
  2. If you are installing a non-air gap faucet, fit the flat rubber washer. Ignore this step if you are installing an air-gap faucet
  3. Slide on the big chrome base plate and the big rubber washer underneath the faucet body
  4. Slide the plastic washer from under the sink
  5. Screw on the brass hex tightly once the faucet is well aligned
Drain Saddle Installation

Place the drain saddle preferably at the highest possible point above the water in the trap and far from the waste disposal drains.

  1. Drill a hole of approximately a 1/4 inch in diameter through a side of the pipe once you identify the point of your drain saddle.
  2. Attach the drain clamp with its hole in line with the hole in the pipe
  3. Tighten the clamp well enough for easy removal when you want to do maintenance
Tube Connections
  1. The tank tube is connected from the filter to the tank valve.
  2. The faucet tube is fixed from the faucet bottom to the fitting adjacent to the tank and tightened firmly.
  3. The drain fitting is behind the membrane system. The drain tube is kept short and connected to the drain saddle.

Maintenance and Care

Proper maintenance can allow high-quality RO systems to last for many years. Proper maintenance involves regular filter replacements and an annual sanitization of the system. The sediment filter, carbon filter and polishing filter will have to be replaced annually while the reverse osmosis membrane can be replaced every two to three years. Note that failure to replace filters can cause damage to the system and decrease the water production.

Annual Sanitation

You may have to consult the owner’s manual for details on how to sanitize the system. These are the general steps:

  1. Turn off the main valve
  2. Drain out all the water from the faucet
  3. Detach the sediment and carbon filters
  4. Detach the reverse osmosis membrane
  5. Screw the housings back in place without the filters
  6. Pour 1 cup of hydrogen peroxide into the stage one housing
  7. Reattach the all the tube connections
  8. Turn on the main valve
  9. Let the system run through at least 2 cycles without the filters
  10. Turn off the main valve
  11. Install the new filters
  12. Allow the system to run through 1 complete cycle

What is the Best Reverse Osmosis System for Home Use?

  • 6 Stages
    1. Sediment Filter
    2. GAC Carbon
    3. CTO Carbon
    4. RO Membrane
    5. Post Carbon
    6. pH Filter
  • Pressure: 45-70 psi
  • Alkaline Remineralization raises pH level and improves taste
  • 75 Gallon per day capacity
  • Live phone support
  • 1-year money back guarantee

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The 6-stage, high-capacity Reverse Osmosis system by iSpring features a remineralization filter which raises alkalinity at the final stage. With a 75-gallon per-day capacity, this RO system can produce a large enough volume of purified water to support an entire household. PSI range is at 45-70. iSpring offers a 1-year money back guarantee and live phone support for their products.

  • 5 Stages
    1. Sediment Filter
    2. 1st Carbon Block
    3. 2nd Carbon Bloack
    4. RO Membrane
    5. Refining Carbon Filter
  • Pressure: 45-70 psi
  • 90 Gallon per day capacity
  • Made in the USA

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The 5-stage Reverse Osmosis system by APEC features a sediment filter, 2 carbon block filters, the RO membrane, and a final refining carbon filter to polish the water's taste before exiting the faucet. At a high 90-gallon per day capacity, this RO system provides enough purified water for a whole household to meet its daily needs, and then some. APEC prides itself in manufacturing and assembling all its parts in the United States.

  • 7 Stages
  • Pressure: 40-90 psi
  • Filter housing is replaced with filter
  • Larger fittings and tubing for faster flow
  • Non-electric pump for improved efficiency
  • 5-year limited warranty

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The 7-stage home reverse osmosis system by Home Master features an upright design with modular filters for easy access and replacement. While most RO systems require filters alone to be replaced periodically, the Home Master system replaces the entire module. Modules are required to be replaced periodically anyway, so the Home Master system allows you to do so with the filter. With larger fittings and tubing, along with a non-electric water pump, the Home Master system has a much faster flow and is much more water efficient than most RO systems.

  • 4 Stages
    1. Sediment Filter
    2. Pre Carbon
    3. RO Membrane
    4. Post Carbon
  • Pressure: 40-120 psi
  • Patented water-saving technology - 10 times more water efficient
  • Clean, space-saving design

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Brondell's Circle reverse osmosis system features 4 essential stages including the sediment filter, the pre-carbon filter, the RO membrane, and the post-carbon filter. The Circle can handle a wide range of water pressures at 40-120 psi. What makes the Circle unique is its clean, space-saving design. At 13" x 9" x 16", the rectangular tower doesn't have any filters or tubing exposed and fits nicely underneath the sink. Brondell prides itself in manufacturing an RO system that doesn't waste as much water as most systems. With their patented water-saving technology, the Circle is 10 times more water efficient than the average RO system on the market.

  • 5 Stages
    1. Sediment Filter
    2. Carbon Block
    3. Granular Carbon
    4. RO Membrane
    5. Post Carbon
  • Pressure: 40-80 psi
  • 50 Gallons per day capacity
  • Lifetime Support
  • 1-year warranty

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The Express Water reverse osmosis system features 5 stages: sediment, carbon block, granular carbon, RO membrane, and post carbon. At 40-80 psi and 50 gallons per day, this system provides more than enough clean water for an entire household. Express Water features a 1-year warranty and lifetime support.


Reverse osmosis has proven to be an efficient and cost effective way of purifying water of bacteria, viruses, sediment, solvents, and chemicals. Many RO systems come with several additional stages for extra features and filtration. While some of these features are certainly beneficial, the core components of an effective RO system are the sediment and carbon filters, the RO membrane, and the holding tank. Be sure to select a system that best fits your needs and your budget.

Thank you for taking the time to read our article on the best reverse osmosis system for home use. We'd love to hear your feedback in the comments section below. If you've found this article to be useful and are interested in learning more, be sure to sign up for our newsletter.


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H20 Distributors. (n.d.). Reverse Osmosis System Installation Guide - H2O Distributors. Retrieved from

How Stuff Works. (2008, May 8). How Reverse Osmosis Works. Retrieved from

Pure Aqua. (n.d.). What is Reverse Osmosis & How does it work? Retrieved from

Puretec. (n.d.). Puretec Industrial Water | What is Reverse Osmosis? Retrieved from

Water Advise. (2016, June 25). Advantages Of A Reverse Osmosis Water System Over Other Purification Methods. Retrieved from

Water Right. (n.d.). Benefits of Drinking Reverse Osmosis Water | Water-Right. Retrieved from

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