Reverse osmosis filters remove the most contaminants from unfiltered water thanks to a semi-permeable membrane. For homes with serious contamination issues or if you just want the purest water possible, then a reverse osmosis (RO) filtration system is the best option.
The unique filtration process in reverse osmosis filters makes it an exceptional choice for whole home filtration or under sink filters. We’ll show you how these filters work and what contaminants they remove.
How Does Reverse Osmosis Work?
Reverse osmosis is unlike any other water filter. It doesn’t use carbon block or mesh netting. Instead, it uses a semi-permeable membrane with small pores that filter out contaminants and allow water molecules to flow through.
These filters use the process of reverse osmosis, which pushes or pressures water through the membrane, which captures all of the toxins and contaminants. The contaminants are deposited and flushed away.

In RO filtration, there are multiple stages to ensure that there is a 99.99% purification. These stages include:
• Sediment pre-filter
• Activated carbon filter
• Reverse osmosis membrane
The carbon filter removes some of the chemicals that may flow past a reverse osmosis membrane, such as volatile organic compounds and chlorine.
The reverse osmosis membrane removes everything else, including total dissolved solids (TDS).
Contaminants Removed by Reverse Osmosis Filters
When it comes to lead, arsenic, fluoride, and herbicides, reverse osmosis systems have proven to be incredibly powerful. Some of the contaminants removed with reverse osmosis include:
There are hundreds of other contaminants that reverse osmosis membranes prevent from getting in your water. It’s important that other stages of filtration also be used in combination with reverse osmosis to ensure that chemicals don’t damage the membrane.
- Fluoride
- Nitrates/nitrites
- Arsenic
- Herbicides
- Lead
- Copper
- Radium
- Sulfate
- Potassium
- Mercury
- Calcium
- Asbestos
- Iron
Is Reverse Osmosis Water Good for You?
There have been some water filter systems that don’t include the other stages of filtration. The World Health Organization also has said that long-term consumption of reverse osmosis filtered water can lead to adverse health effects. This is why it’s important to have a pre-sediment filter, activated carbon filter, and a demineralization feature. This makes the water safer and tasty to drink.