RO Contaminant Rejection Table

The reverse osmosis process utilizes a semipermeable membrane to remove a wide variety of contaminants. Here is a partial list.

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%

Lead

95 - 98%

Arsenic

92 - 96%

Magnesium

94 - 98%

Nickel

96 - 98%

Fluoride

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.

Reverse Osmosis System Contaminant Removal Chart