Reverse Osmosis


water treatment systems

What Is Reverse Osmosis?

Reverse Osmosis is a very fine filtration process, which occures at a molecular level. The process involves forcing water through a semi-permiable membrane, which allows only a given size of molecule to pass, and rejects the rest. In effect, the pores or holes in the membrane are so small that most of the harmful minerals and chemicals cannot pass, while water molecules pass through.

The rejected water carrying the minerals in a high concentration is drained off through the waste water pipe, and the pure water is diverted to the storage tank for drinking. The  Reverse Osmosis Filtration System removes up to 95% of harmful minerals and chemicals, the system also removes suspended impurities such as dirt, sand and rust, it improves the odor and taste of your municipal water and leaves good, clean and health water for your consumption.

Although Reverse Osmosis systems look complex, it is really a simple and straightforward water filtration process. And it’s not a new process. High-pressure (pump driven) reverse osmosis systems have been used for years to desalinate* water – to convert brackish or seawater to drinking water. Having a better understanding of how a reverse osmosis system works will eliminate the mystery and confusion you may feel when you look at a reverse osmosis system with its many colored tubes and multitude of filters. Read on to enhance your knowledge of residential reverse osmosis systems.

The most important reverse osmosis points to remember:

  • All Reverse Osmosis Systems work the same way.
  • Most RO (Reverse Osmosis) systems DO NOT look alike
  • We have RO systems for home use and we have RO systems for industrial use.
  • All RO Systems have the same basic components.
  • The difference is the quality of the filters and membranes inside the Reverse Osmosis system.

How does a Reverse Osmosis Membrane work?

Reverse Osmosis is a process in which dissolved inorganic solids (such as salts) are removed from a solution (such as water). This is accomplished by household water pressure pushing the tap water through a semi permeable membrane. The membrane (which is about as thick as cellophane) allows only the water to pass through, not the impurities or contaminates. These impurities and contaminates are flushed down the drain.

Advantages Of Reverse Osmosis

  • Improves taste, odor and appearance.
  • Highly effective purification process. Will remove the pollutants listed below and more!
  • Consumes no energy
  • Very convenient
  • Flushes away pollutants, does not collect them
  • Easy to keep clean
  • Low production cost – gives you water of a guaranteed quality for pennies per gallon

For a definition of **Reverse Osmosis. Ultimately, the factors that affect the performance of a Reverse Osmosis System are:

  • Incoming water pressure
  • Water Temperature
  • Type and number of total dissolved solids (TDS) in the tap water
  • The quality of the filters and membranes used in the RO System (see operating specs)

Discover the advantages

RO system helps remove impurities in the water and leaves you with refreshing and great tasting water. Critical filtration steps have to be taken before purification of the water.

  • Clean and clear water is the key to a better health
  • We are here to help with whatever you need to know about Water Purification
  • All the technical support you need based on our products
  • Starting a water business has never been so easy
Reverse Osmosis Membrane

What are the components of Reverse Osmosis System?

Basic components common to all Reverse Osmosis Systems:

  • Cold Water Line Valve: Valve that fits onto the cold water supply line. The valve has a tube that attaches to the inlet side of the RO pre filter. This is the water source for the RO system.
  • Pre-Filter (s): Water from the cold water supply line enters the Reverse Osmosis Pre Filter first. There may be more than one pre-filter used in a Reverse Osmosis system. The most commonly used pre-filters are sediment filters. These are used to remove sand silt, dirt and other sediment. Additionally, carbon filters may be used to remove chlorine, which can have a negative effect on TFC (thin film composite) & TFM (thin film material) membranes. Carbon pre filters are not used if the RO system contains a CTA (cellulose tri-acetate) membrane.
  • Reverse Osmosis Membrane: The Reverse Osmosis Membrane is the heart of the system. The most commonly used is a spiral wound of which there are two options: the CTA (cellulose tri-acetate), which is chlorine tolerant, and the TFC/TFM (thin film composite/material), which is not chlorine tolerant.
  • Post filter (s): After the water leaves the RO storage tank, but before going to the RO faucet, the product water goes through the post filter (s). The post filter (s) is generally carbon (either in granular or carbon block form). Any remaining tastes and odors are removed from the product water by post filtration.
  • Automatic Shut Off Valve (SOV): To conserve water, the RO system has an automatic shutoff valve. When the storage tank is full (this may vary based upon the incoming water pressure) this valve stops any further water from entering the membrane, thereby stopping water production. By shutting off the flow this valve also stops water from flowing to the drain. Once water is drawn from the RO drinking water faucet, the pressure in the tank drops and the shut off valves opens, allowing water to flow to the membrane and waste-water (water containing contaminants) to flow down the drain.
  • Check Valve: A check valve is located in the outlet end of the RO membrane housing. The check valve prevents the backward flow or product water from the RO storage tank. A backward flow could rupture the RO membrane.
  • Flow Restrictor: Water flow through the RO membrane is regulated by a flow control. There are many different styles of flow controls. This device maintains the flow rate required to obtain the highest quality drinking water (based on the gallon capacity of the membrane). It also helps maintain pressure on the inlet side of the membrane. Without the flow control very little drinking water would be produced because all the incoming tap water would take the path of least resistance and simply flow down the drain line. The flow control is located in the RO drain line tubing.
  • Storage Tank: The standard RO storage tank holds up to 2.5 gallons of water. A bladder inside the tank keeps water pressurized in the tank when it is full.
  • Faucet: The RO unit uses its own faucet, which is usually installed on the kitchen sink. In areas where required by plumbing codes an air-gap faucet is generally used.
  • Drain line: This line runs from the outlet end of the Reverse Osmosis membrane housing to the drain. This line is used to dispose of the impurities and contaminants found in the incoming water source (tap water). The flow control is also installed in this line.
Reverse Osmosis Flowchart

Are all Reverse Osmosis Systems and filters the same?

While one RO System may look just like the next in terms of design and components, the quality of those components can be very different. These differences can have a significant impact on the quality of the water the system produces.

Here are some examples of questions you might ask and consequences associated with “less than desirable” quality.

Has the manufacturer used sound methods? What types of welds have been used in these plastic products? Will they allow contaminated water to bypass the filtration system? Will they allow the system to leak?

How has this filter or membrane been created? Will it allow the water to ‘channel’ and, in effect, bypass the removal component of this device?

What about the quality of the ‘fill’? Are its contents of a high enough quality to produce the expected percentage of contaminant reduction? Carbon quality, for instance, can have huge variances in reduction capability, reduction capacity, and the sloughing of ‘fines’, which can prematurely clog or foul the RO Membrane.

What are the manufacturer’s controls on tolerances or variations in specifications? If this component is rated as a 1-micron filter will it truly filter out everything larger than 1 micron or will it only do the job 80% of the time? And, what if it actually filters at a .5-micron rate? That will stop the system from flowing — clogging it and forcing filter replacement? If this is a sediment filter and it fails the excess sediment will clog or foul the RO Membrane.

And in general – Are the materials used in this product FDA or NSF (National Safety Foundation) approved? If not, you might question their quality or performance ability. So, it becomes clear that the quality of the components is the key to an optimal functioning RO System.

So, it becomes clear that the quality of the components is the key to an optimal functioning RO System.

How do you increase the gallons per day (GPD) capacity of the reverse osmosis membrane?

The main reason to change to a higher flow reverse osmosis membrane is to improve the recovery rate which is to reduce the amount of time it takes to refill the storage tank. This insures that there is adequate water available during times of heavy usage or when the reverses osmosis system may feed more than one location such as an ice maker and a dispensing faucet.

Changing to a higher flow membrane has no effect on the quality of the water your reverse osmosis system makes or the length of time the reverse osmosis membrane will last.

The change to a higher capacity membrane is easy. You simply replace your old membrane with a new, higher capacity membrane, along with the correctly sized drain line flow restrictor. (Matching the membrane with the correctly sized drain line flow restrictor is important to ensure the proper product to waste ratio is meet. A mis-matched combination will allow either excess water to flow to the drain or cause premature fouling of the membrane.) Most standard reverse osmosis membrane housings will accommodate membranes ranging in capacities from 10 – 150 gallons per day.

Flow Control Installation Instructions

A complete listing of standard residential reverses osmosis membranes and corresponding drain line flow controls is on our membrane page or review the flow control guideline chart for residential reverse osmosis membranes on our parts page.


We carry replacement filters and membranes for most major brands of Reverse Osmosis systems. View our list of Reverse Osmosis Filters by brands that we carry.

We also have new Reverse Osmosis Systems available to purchase. See the features and benefits of each type of Reverse Osmosis System.

Reverse Osmosis Products

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Do you have ro systems that are suitable for home use? If so, which system would you recommend for me?

We offer reverse osmosis system for home use all the way to industrial usage.

The reverse osmosis systems differ with your home water pressure. If you have 3 bars of water pressure, we can recommend the 50GPD RO Systems without pump. But if you have less than 3 bars of water pressure, we recommend 50GPD with a pump, but, you will need at least 1.5 bar of water pressure for the pump to kick in to give you the required flow-rate.

“GPD” stands for Gallons Per Day. The amount of pure water you will get a day.

These Reverse Osmosis systems work with municipal water and that also depends on the quality of the water. Should the water be of bad quality, we recommend you put pre-filtration before the water goes into the house.

For municipal water, the pre-filtration that we recommend is of the Whole House Water Filtration System. This unit consists of three 20″ Big Blue Filter Housings (R450 Excl. VAT), two (1st and last filter) 20″ Big Blue Sediment Filters and one (middle filter)  20″ Big Blue Carbon Block Filter (R200 Excl. VAT).

The first filter (Sediment Filter), is used to capture all the small particles such as rust, dust and mud. The second filter (Carbon Block Filter), is used to remove chemicals (Chlorine) out of the water and to remove the bad smell from the water. The third filter (Sediment Filter), is used to polish the water before making its way into your house.

I want to start a water business and I want to purify bore hole water. How do I go about?

Firstly, we will need you to get the borehole analyzed at a lab and send us the analysis results. By doing so , we will be able to know what is in the water and what we need to offer you to be able to purify the water.

We will also need to know the amount of water you want to purify pre hour or per day. Our machines are built according to the required flow rate, so, you telling us the flow rate we will know which machine to offer you.

Are your machines easy to install or your technicians are required to be there?

It depends on the type of machine you want to install. If it is the domestic systems, they are easy to install if you follow the instructions well.

If it is and industrial unit you want installed, our technicians are required to do the job as they well trained specifically to install such machines.

It depends on the type of machine you want to install. If it is the domestic systems, they are easy to install if you follow the instructions well.

If it is and industrial unit you want installed, our technicians are required to do the job as they well trained specifically to install such machines.