
WHAT DOES A REVERSE OSMOSIS SYSTEM REMOVE
Reverse osmosis (RO) systems can remove common contaminants from water including nitrates, pesticides, sulfates, fluoride, bacteria, pharmaceuticals, arsenic and much more.
For decades, Reverse Osmosis water filtration has proven to be unrivaled when it comes to removing impurities from water in an efficient and cost-effective manner. Because Reverse Osmosis can effectively remove a wide range of impurities, RO technology is becoming increasing popular.
Can Reverse Osmosis Remove Bacteria?
Reverse Osmosis technology is not designed to remove bacteria and viruses. If bacteria enters the RO system, it can continually grow in pre-filters and deteriorate the membrane over time. Thus, most RO system manufacturers specify that the system "must be used with biologically safe water". Bacteria and virus removal is best achieved with a UV water sterilizer system. We highly recommend pairing a whole-house UV water sterilizer system (installed at your home's water point of entry), with a Reverse Osmosis drinking water system installed under the kitchen sink.
What Can a Reverse Osmosis Drinking Water Filter System Remove?
The reverse osmosis process utilizes a semipermeable membrane to remove a wide variety of contaminants. Here is a partial list of impurities removed by RO.
TYPICAL REJECTION CHARACTERISTICS OF R.O. MEMBRANES Elements and the Percent R.O. Membranes will remove
Sodium |
85 - 94% |
Sulfate |
96 - 98% |
Calcium |
94 - 98% |
Potassium |
85 - 95% |
Nitrate |
60 - 75% |
Iron |
94 - 98% |
Zinc |
95 - 98% |
Mercury |
95 - 98% |
Selenium |
94 - 96% |
Phosphate |
96 - 98% |
95 - 98% |
|
Arsenic |
92 - 96% |
Magnesium |
94 - 98% |
Nickel |
96 - 98% |
85 - 92% |
|
Manganese |
94 - 98% |
Cadmium |
95 - 98% |
Barium |
95 - 98% |
Cyanide |
84 - 92% |
Chloride |
85 - 92% |
During the multi-stage filtration process of an RO system, water will pass through pre-filters (to remove sediment, large particles and chlorine), then on to a semi permeable RO membrane (which can remove most impurities down to .001 microns), as well as a post filter (generally a carbon filter to improve taste).
The chart below demonstrates to what level the RO system will successfully remove or reject impurities (typically down to .001 microns). For example, if fluoride is your main concern, you see that an RO system will eliminate up to 92% of it from your water.
Best Reverse Osmosis Water Filter Systems 2021
These under-sink Reverse Osmosis (RO) systems are top-rated for removing a wide variety of contaminants:
50 GPD Reverse Osmosis System
PuROTwist 4000

- Quick-Change No-Mess Replacement Filters Under Sink
- Compact Size for Simple Installation Under Sink
- 50 Gallon Per Day Rated Membrane
- 4-Stages of Filtration
- Made in USA
- Free Shipping
100 GPD Reverse Osmosis System
Watts Kwik Change 4-Stage

- Quick-Change No-Mess Replacement Filters
- 100 Gallon Per Day Rated Membrane
- 4-Stages of Filtration
- Designer Faucet
- Space-Saver Storage Tank Only 9” Wide
- FREE Shipping