Reverse Osmosis (RO) works by filtering water through a semi-permeable membrane that won't allow most contaminents to pass through. They generally use a process called cross flow, which ensures that they are constantly cleaning themselves. The down-side to RO is that typically, it will only recover between 5% and 15% of the water entering the system, the rest is waste.
| Name & Website | Based | Suitability | Online Ordering | Secure Site |
| Osmonics | USA | Whole House | NO | N/A |
| Aquatic Reef Systems | USA | Various | YES | YES |
| Premier Water Systems | USA | Various | YES | YES |
For a comparison of the advantages and disadvantages of reverse osmosis against other water treatment methods, you may wish to look at the water treatment comparison page.
I have tried to keep my site as concise as possible, so should you require further information on reverse osmosis, then you many find any of the following sites useful: