Reverse Osmosis Filtration is accomplished by forcing water through a membrane with pores that are .0001 microns, which is smaller than 1 millionth of an inch.  All reverse osmosis systems require pre-filtration. Reverse osmosis systems reject water to the drain. On the larger systems, such as whole house systems, the reject water is recirculated through the membrane again. 

Reverse osmosis membranes can get clogged and damaged by many contaminants. High levels of hardness, iron, sulfur, and chlorine must be removed prior to the water going to the membrane. We also recommend annual servicing to ensure the best quality water to your household. 

Bottled water where the label says ‘purified’ is filtered by reverse osmosis such as with Pepsi and Coke’s Dasani and Aquafina. In the water industry, we have agreed to only use the word purified if the water has been filtered to the sub-micron level as with the process of reverse osmosis.