What is Reverse Osmosis and How Does it Work

What is Reverse Osmosis and How Does it Work

What is Reverse Osmosis and How Does it Work


If you are looking for a water purifier that will provide outstanding drinking water for your home, Reverse Osmosis (RO) filtration is one of the most popular and best options available.

Below you will find 6 of the most common questions about Reverse Osmosis systems.

1.Why is reverse Osmosis a good water filtration option?

  • Improves taste. RO filtration improves taste, odour and appearance of water by removing contaminates that cause taste and odour problems
  • Saves money. With an RO system, you can cancel your water delivery service and stop buy cases of bottled water. Reverse osmosis filtration provides “better-than-bottled-water” quality water for just pennies per gallon.
  • Simple maintenance. RO systems have very few moving or replaceable parts, making RO systems easy to clean and service.
  • Removes impurities. RO systems remove pollutants from water including nitrates, pesticides, sulfates, fluoride, bacteria, pharmaceuticals, arsenic and much more. An RO systems’ carbon filter will also remove chlorine and chloramines.

2.How Does Reverse Osmosis Work?

  • Reverse Osmosis is a process in which dissolved inorganic solids (such as salt) are removed from a solution (such as water). This is accomplished by household water pressure pushing the tap water through a semipermeable membrane and filters.


What happens to contaminates that don’t pass through the membrane?

  • When household water pressure pushes water through the RO membrane and filters, the impurities are filtered out and subsequently flushed down the drain. What is left, is delicious, clean tasting drinking water. Many RO systems contain 4-5 stages to provide optimal water quality.

3. RO Filter systems: What are the basic components of a reverse osmosis system?  

  • Cold water line valve: Calve 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 an RO system, the most common being sediment and carbon filters. These pre-filters are used to PROTECT the RO membranes by removing sand silt, dirt and other sediment that could clog the system. Additionally, carbon filters may be used to remove chlorine, which can damage the RO membranes.
  • Reverse Osmosis Membrane: The Reverse Osmosis membrane is the heart of the system. The semipermeable RO membrane is designed to remove a wide variety of both aesthetic and health related contaminates. After passing through the membrane, the water goes into a pressurized storage tank.
  • Post Filter(s): After the water leaves the RO storage tank, but before going to the RO faucet, the treated water goes through a final “post filter”. The post filter is usually a carbon filter. Any remaining taste and odours are removed.
  • Storage tank: The standard RO storage tank hold from 2-4 gallons of water. A bladder inside the tank keeps water pressurized in the tank when it is full.
  • Check Valve: a check valve is located in the outlet end if the RO membrane housing. The check valve prevents the backward flow of treated water from the RO storage tank.
  • Faucet: An RO unit uses its own faucet, which is usually installed on the kitchen sink

4. Are all Reverse Osmosis drinking systems and filters the same?

There are many different RO systems on the market. While one RO system may look like the next in terms of design and components, there can be substantial differences between them.

RO systems differ in three (3) main ways;

  1. Number of stages/filters
  2. Amount of Gallons Per Day (GPD) that can be filtered
  3. Quality of the components


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