Reverse osmosis (RO) filter systems can remove a large number of contaminants from the incoming water supply. There is no guarantee that the water is 100% free of contaminants, but there is no filtration method that is this effective. The only methods that are this effective, such as water distillation, are impractical for home use. In this article, we will look at the contaminants that a RO filter system can remove.

What is Reverse Osmosis (RO) Filtration?

Reverse osmosis is a water filtration method that’s purely mechanical in nature. No chemicals are added at any stage during this process, and at the heart of the system, there is a semi-permeable filter membrane. This membrane has tiny pores which prevent most molecules from passing through except water and trace contaminants. This is not pure H2O, but it’s the closest that you can get to pure water at the time of writing this article. The incoming water cannot pass through the filter membrane until it’s placed under pressure. This process takes some time, an on-demand system is not practical, and the filtered water is stored in a tank until it’s needed.

Whole-Home or Point-of-Use Systems?

As the name suggests, a whole-home RO filter system is larger, and it can deliver RO water to every faucet and fixture in the home. If you want to shower in RO water, this is the water filtration system to meet your needs. The main drawback is that a whole-home system is more expensive, and it’s beyond the financial reach of most people.

A good alternative is a point-of-use RO filtration system which is installed at a single location. The usual position is at the kitchen sink, with the storage tank located underneath. The RO water is delivered to a dedicated faucet to fill pitchers, make ice, wash vegetables, and more. These systems are more affordable, and the drinking water is cleaned to a very high standard.

Which Contaminants are Removed?

The RO filter membrane has pores that reject any material that exceeds 100 MW (Molecular Weight) units. To put this into some perspective, 95-99% of inorganic materials are removed from the water. Some common inorganic contaminants that are removed are calcium, copper, strontium, sodium chloride, and others. But, the filter membrane can remove organic contaminants, too, including bacteria, viruses, cysts, and more, with an effectiveness of 99.9%. So, RO drinking water is virtually bacteria and virus free, which is healthier and safer for consumption.

Although the filter membrane can remove chlorine compounds, it will be degraded and destroyed by chlorine. For this reason, a granular activated carbon (GAC) filter stage is placed before the membrane to remove chlorine. There are usually four filtration stages to make the water safe for RO filtration and to improve the water characteristics: a pre-filter, the initial GAC filter, the RO membrane filter and a second GAC filter to add a final polish.

If you want to install a RO filtration system in your home, contact your local water treatment specialist today.

By EcoWater Systems.
EcoWater Systems of Nebraska is the largest water treatment company in the state and is a member of Water Quality Association.