HOW THE REVERSE OSMOSIS SYSTEM WORKS

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.

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

Diagram of a Reverse Osmosis Membrane

See a video with a great explanation on how it works

Quality of RO Membranes and Filters – They're not all alike!

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 it's 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.