Below are the typical rejection (removal) percentages of a standard thin film (TFC) reverse osmosis membrane. These are averages based on experience and are generally accepted within the industry. They are not a guarantee of performance. Actual rejection can vary according to the chemistry of the water, temperature, pressure, pH and other factors.
The reverse osmosis process uses a semi-permeable membrane to reject a wide variety of impurities. Here is a partial list.
| Aluminum | 97-98% | Nickel | 97-99% |
| Ammonium | 85-95% | Nitrate | 93-96% |
| Arsenic | 94-96% | Phosphate | 99+% |
| Bacteria | 99+% | Polyphosphate | 98-99% |
| Bicarbonate | 95-96% | Potassium | 92% |
| Boron | 50-70% | Pyrogen | 99+% |
| Bromide | 93-96% | Radioactivity | 95-98% |
| Cadmium | 96-98% | Radium | 97% |
| Calcium | 96-98% | Selenium | 97% |
| Chloride | 94-95% | Silica | 85-90% |
| Chromate | 90-98% | Silicate | 95-97% |
| Chromium | 96-98% | Silver | 95-97% |
| Copper | 97-99% | Sodium | 92-98% |
| Cyanide | 90-95% | Sulphate | 99+% |
| Ferrocyanide | 98-99% | Sulphite | 96-98% |
| Fluoride | 94-96% | Zinc | 98-99% |
| Iron | 98-99% | ||
| Lead | 96-98% | Insecticides | 97% |
| Magnesium | 96-98% | Detergents | 97% |
| Manganese | 96-98% | Herbicides | 97% |
| Mercury | 96-98% | Virus | 99+% |
| TDS (Total Dissolved Solids) | 95-99% | Hardness | 93-97% |
Read the results of an extensive test performed by Dr. Charles Moretti of the University of North Dakota using our Black & White units with Desal and Filmtec membranes. Go here for the full study, “Point-of-Use Reverse Osmosis Treatment for Removal of Arsenic from Drinking Water”
(whole house & well units)