Organic scavenger resins have been used commercially in water filters as early as 1997. As an alternative to reverse osmosis, organic anion resins (scavenger resins) have been used to remove impurities from drinking water. These types of resins are able to remove the negatively charged organic molecules in water, like bicarbonates, sulfates, and nitrates. It has been estimated that 60–80% of organic impurities in water may be remove using these methods.